JPH087352B2 - Optical matrix switch device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical matrix switch device that electrically switches a transmission path of an optical signal and that has no polarization dependence.

(Prior Art) An optical matrix switch configured by providing a waveguide and an optical switch on a substrate has advantages such as a small size and a small operating voltage, and its research and development are actively conducted. ing.

This kind of optical switch uses the optical effect such as electro-optic effect and acousto-optic effect to switch the signal light, but research on the optical switch using the electro-optic effect as an optical device suitable for practical use has been conducted. It is progressing. This optical switch is configured by using a ferroelectric crystal substrate having an electro-optical effect represented by a LiNbO ₃ substrate, for example. When an electric field (electric field) is applied to the electro-optic crystal substrate via the control electrode, the refractive index of this substrate changes, so that signal light switching can be performed by utilizing the change in the refractive index. The change in the refractive index is closely related to the direction P of the electric field applied to the substrate and the vibration direction (biasing direction) Q of the electric field of the signal light,
When the electric field direction P is a specific direction and the eccentric direction Q is a specific direction, the refractive index can be efficiently changed at a low operating voltage (the electro-optical effect becomes large). However, these electric field direction P and bias direction Q
As is shifted from a specific direction, a larger operating voltage is required to change the refractive index, resulting in poor efficiency (electro-optical effect becomes smaller). Because of this,
Usually, the conventional optical switch utilizing the electro-optical effect is configured so that the light can be switched only when the input signal light has a specific polarization direction. Therefore, there is polarization dependency that switching may or may not be performed depending on the bias direction of the input signal light.

On the other hand, Reference I “Journal of Lightwave Technology
(Journal of Light Wave Technology) "Optical switch that does not have polarization dependence, such as the optical switch proposed in" Vol.LT-4.NO.11 NOVEMBER 1986 pp.1717 ", is being studied. There is. In the optical switch of Document I, LiNbO ₃ having the above-mentioned properties as a substrate is used.
Using a substrate, the signal light having a specific polarization direction and the signal light having a polarization direction different from the specific polarization direction are input and configured to switch between these two signal lights. .

Further, there has been conventionally proposed a device which is configured by using a compound semiconductor substrate such as GaAs or InP and which switches the signal light by utilizing the electro-optical effect. However,
An optical switch utilizing the electro-optic effect that has been proposed hitherto requires an excessive operating voltage for light in a bias direction different from a specific direction, and cannot substantially perform switching control.
For this reason, it had polarization dependency. Therefore, in order to eliminate the polarization dependence, there has been proposed one in which the refractive index of the compound semiconductor substrate is changed by current injection. In this optical switch, the optical switch is operated in the total reflection state or the transmission state by changing the refractive index of the current injection region, thereby switching the signal light.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional optical switch having no polarization dependence of Document I, not only the signal light having a specific polarization direction in which electro-optic becomes large, but also the electro-optic effect is obtained. In order to switch even the signal lights having different polarization directions with a small deviation, an operation voltage of about 5 to 6 times or more is required as compared with the operation voltage in the case of switching only the signal light having a specific polarization direction. There was a problem that was.

In addition, in a polarization-independent optical switch that uses a compound semiconductor substrate, the change in the refractive index of the substrate is controlled by injecting current, so current consumption is higher than that in an optical switch that uses the electro-optical effect. However, there is a problem in that the number of lights increases and the operation speed of the optical switch becomes slow.

An object of the first invention of this application is to solve the above-mentioned problems of the conventional optical switch constructed by using a ferroelectric crystal substrate, and to perform polarization-independent switching at a lower operating voltage. An object is to provide an optical matrix switch device.

A second object of the present application is to solve the above-mentioned problems of the optical switch formed by using the compound semiconductor substrate, reduce the current consumption, and increase the operating speed. It is to provide a non-optical matrix switch device.

(Means for Solving the Problems) In order to achieve this object, the first invention of the present application is configured by using a ferroelectric crystal substrate and has a large electro-optical effect having bias directions orthogonal to each other. Polarization and polarization with a small electro-optical effect are input using a pre-stage optical matrix switch and a ferroelectric crystal substrate. The optical matrix switch in the latter stage where a small amount of polarized light is input is connected in series with these optical matrix switches in the former stage and the latter stage, and the polarization direction output from the control optical switch of the preceding stage optical matrix switch is rotated by 90 °. And a bias changing means for inputting to the control optical switch of the optical matrix switch in the subsequent stage. Is selectively operated in a bar state or a cross state for polarized light having a large electro-optical effect, and one of a bar state and a cross state for polarized light having a small electro-optical effect. It is characterized by being configured as an optical switch that operates non-selectively in a state.

Further, according to the optical matrix switch device of the second invention of this application, a polarized light having a large electro-optical effect and a polarized light having a small electro-optical effect, which are configured by using a compound semiconductor crystal substrate and have polarization directions orthogonal to each other. An optical matrix switch in the front stage to be input, and a light matrix in the rear stage to which polarized light having a large electro-optical effect and polarized light having a small electro-optical effect, which are composed of a compound semiconductor crystal substrate and have polarization directions orthogonal to each other, are input. The switch and the optical matrix switches in the front and rear stages are connected in series, and the polarization direction output from the control optical switch in the front optical matrix switch is rotated by 90 ° to become the control optical switch in the rear optical matrix switch. Equipped with bias changing means for inputting, the control optical switch of the optical matrix switch in the front and rear stages For polarized light with a large optical effect, it selectively operates in the bar state or cross state, and for polarized light with a small electro-optical effect, it is unselected in either the bar state or the cross state. It is characterized in that it is configured as an optical switch that operates normally.

(Operation) According to the optical matrix switch device of the first invention having such a configuration, polarized light having a large electro-optical effect and polarized light having a small electro-optical effect having polarization directions orthogonal to each other are transmitted via the polarization polarization means. , Input from the matrix switch at the front stage to the matrix switch at the rear stage.

At this time, the polarized light polarization means converts polarized light having a large electro-optical effect into polarized light having a small electro-optical effect, and converts polarized light having a small electro-optical effect into polarized light having a large electro-optical effect. Therefore, the polarized light having a large electro-optical effect input to the optical matrix switch in the previous stage is converted into the polarized light having a small electro-optical effect and input to the optical matrix switch in the subsequent stage,
Further, the polarized light having a small electro-optical effect inputted to the optical matrix switch in the preceding stage is converted into the polarized light having a large electro-optical effect and inputted to the optical matrix switch in the succeeding stage.

The control optical switches that constitute the optical matrix switches in the front and rear stages selectively operate in a bar state or a cross state for polarized light having a large electro-optical effect, so that the propagation path is selectively operated at a low operating voltage. Can be changed to In addition, the control optical switches that form the optical matrix switches in the front and rear stages operate non-selectively in either the bar state or the cross state for polarized light with a small electro-optical effect, so that a specific input is possible. It provides a fixed propagation path that connects between output ports.

Therefore, for polarized light having a large electro-optic effect input to the optical matrix switch in the previous stage, the propagation path can be selectively changed in the optical matrix switch in the previous stage with a low operating voltage. With respect to the polarized light having a small electro-optical effect, which is input to the optical matrix switch, the propagation path can be selectively changed with a low operating voltage in the optical matrix switch in the subsequent stage.

Even when the front and rear optical matrix switches are formed by using the ferroelectric crystal substrate in this way, the polarization of the electro-optical effect that is large and the polarization of the electro-optical effect that is input to the optical matrix switch of the preceding stage are small. The propagation path can be selectively changed at low operating voltage for both polarizations.

According to the optical matrix switch device of the second invention,
Polarized light having a large electro-optical effect and polarized light having a small electro-optical effect having polarization directions orthogonal to each other are input from the matrix switch in the preceding stage to the matrix switch in the subsequent stage via the bias changing means.

At this time, the polarized light polarization means converts polarized light having a large electro-optical effect into polarized light having a small electro-optical effect, and converts polarized light having a small electro-optical effect into polarized light having a large electro-optical effect. Therefore, the polarized light having a large electro-optical effect input to the optical matrix switch in the previous stage is converted into the polarized light having a small electro-optical effect and input to the optical matrix switch in the subsequent stage,
Further, the polarized light having a small electro-optical effect inputted to the optical matrix switch in the preceding stage is converted into the polarized light having a large electro-optical effect and inputted to the optical matrix switch in the succeeding stage.

The control optical switches that constitute the optical matrix switches in the front and rear stages selectively operate in a bar state or a cross state for polarized light having a large electro-optical effect, so that the propagation path is selectively operated at a low operating voltage. Can be changed to In addition, the control optical switches that form the optical matrix switches in the front and rear stages operate non-selectively in either the bar state or the cross state for polarized light with a small electro-optical effect, so that a specific input is possible. It provides a fixed propagation path that connects between output ports.

Therefore, with respect to the polarized light having a large electro-optic effect which is input to the optical matrix switch in the preceding stage, the propagation path can be selectively changed in the optical matrix switch in the preceding stage, and further input to the optical matrix switch in the preceding stage. For polarized light having a small electro-optic effect, the propagation path can be selectively changed in the optical matrix switch in the subsequent stage.

Even when the former and latter optical matrix switches are configured by using the compound semiconductor crystal substrate in this way, both the polarized light having a large electro-optical effect and the polarized light having a small electro-optical effect input to the optical matrix switch in the preceding stage are used. With respect to the polarized light of, the propagation path can be selectively changed when the electro-optical effect is large. Therefore, even when the compound semiconductor substrate is used, the polarization-independent switching operation can be performed by utilizing the electro-optical effect. realizable.

Embodiments Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the drawings are only schematically shown to the extent that the present invention can be understood, and therefore the dimensions, shapes, arrangement relationships, forming materials, constitutions and numerical conditions of the respective constituent components are not limited to the illustrated examples. Absent.

<First Invention> First Embodiment (Explanation of Overall Configuration) In the first embodiment, an example in which the optical matrix switches at the front stage and the rear stage are optical matrix switches having a duplex configuration will be described. FIG. 1 is a perspective view schematically showing the configuration of the first embodiment.

In the figure, reference numeral 28 denotes an optical matrix switch device, which is constituted by using the ferroelectric crystal substrate 12 and has polarization directions and electro-optic effects which have polarization directions orthogonal to each other and have a large electro-optic effect. Pre-stage optical matrix switch (hereinafter simply referred to as pre-stage switch) 10 to which polarized light with a small effect is input, and a ferroelectric crystal substrate
A rear-stage optical matrix switch (hereinafter simply referred to as a rear-stage switch) 24 to which polarized light having a large electro-optical effect and polarized light having a small electro-optical effect, which are configured by using 12 and have polarization directions orthogonal to each other, are input, These front stage switch 10 and rear stage switch 24 are connected in series, and the front stage switch is
Set the polarization direction of the polarization output from the control light switch 20 of 10
A bias changing means 26 is provided which rotates 90 ° and inputs it to the control light switch 20 of the rear stage switch 24.

Then, the control optical switch 20 of the front-stage switch 10 and the rear-stage switch 24 is selectively operated in a bar state (Bar state) or a cross state (Cross state) with respect to polarized light having a large electro-optical effect, and is electrically operated. For polarized light with a small optical effect, it is an optical switch that operates non-selectively in one of the bar state (Bar state) and cross state (Cross state).

In this embodiment, because the front-stage optical switch 10 is configured,
For example, a z-cut LiNbO ₃ substrate is prepared as the substrate 12, and Ti is diffused in the substrate 12 to form four input / output waveguides 14,
Two control optical switches 20 are provided for each input / output waveguide 14. As the control switch 20, for example, an inverted Δβ directional coupling type 2 × 2 optical switch element is used.

Then, the control switches 20 are divided into a first group I and a second group II. Because of this grouping, the first group I
Is composed of four control switches 20 arranged in two rows and two columns by providing two each in the input / output waveguides 14 of the first and second rows, and further includes the second group II in the third and third rows. Each of the input / output waveguides 14 in the fourth row is provided with two switches, each of which is composed of four control switches 20 arranged in two rows and two columns. Then, the control switch 20 of the first group I and the control switch 20 of the second group II are connected to each other by a waveguide 22.
Connect through. As shown in the figure, the control switches 20 provided in the same row of the first group I and the control switches 20 selected so as not to overlap one by one from each row of the second group II are associated one to one. And connect.

The pre-stage switch 10 of this embodiment includes the substrate 12, the input / output waveguide 14, the control switch 20 and the communication waveguide 22 configured as described above.

The left end of the input / output waveguide 14 is denoted by reference numeral 16 and the right end is denoted by reference numeral 18.
Is attached.

Further, the latter stage switch 24 in this embodiment is the former stage switch 10
Therefore, it has the same structure as the above, and therefore comprises the substrate 12, the input / output waveguide 14, the control switch 20, and the communication waveguide 22 which are configured as described above.

Further, in the optical matrix switch device of this embodiment, since the front stage switch 10 and the rear stage switch 24 are connected in series, the right end 18 of the input / output waveguide of the front stage switch 10 and the left end of the input / output waveguide of the rear stage switch 24. 16 and 16 are connected one by one by the bias changing means 26.

Then, the left ends 161 and 162 of the input / output waveguides 14 of the first row and the second row in the front stage switch 10 are used as the input ports of the optical matrix switch device 28, and the first row, the second row, the second row in the rear stage switch 24. The right ends 181, 182, 183 and 184 of the input / output waveguides 14 of the third row and the fourth row are used as output ports of the optical matrix switch device 28. By setting the input / output ports in this way, the light input from the input port 161 or 162 can be selectively output from any one of the output ports 183 and 184.

When a z-cut LiNbO ₃ substrate is used as the substrate 12, polarized light having a large electro-optical effect is TM mode light (also referred to as TM wave) having a polarization direction perpendicular to the substrate surface of the substrate 12, and It is known that polarized light having a small optical effect is TE mode light (also referred to as TE wave) having a polarization direction parallel to the substrate surface of the substrate 12. Therefore, the front switch
For the TM mode light input to 10, the front switch 10
In (1), the propagation path is selectively changed, and the TE mode light input to the front stage switch 10 is rotated by 90 ° by the polarization changing means 26 to be converted into TM mode light. The operating voltage can be lowered by selectively changing the propagation path of the switch 24.

In this way, in order to change the polarization direction of light, for example, a PANDA (panda) type polarization maintaining fiber is used as the polarization changing means 26.

2A and 2B are front views showing the left end face and the right end face of the polarization maintaining fiber as the deviation changing means,
FIG. 2 (A) is connected to the right end of the input / output waveguide of the front stage switch, and FIG. 2 (B) is connected to the left end of the input / output waveguide of the rear stage switch. The right end face of the polarization maintaining fiber is shown in the opened state.

In these figures, S indicates the axis of the bias changing means 26.
On the left end surface 26a and the right end surface 26b, two white circle marks T ₁ and T ₂ are provided for explaining the twisted state of the shaft S, respectively, arranged in a row in the diameter direction. Moreover, the axis S
When the end faces 26a and 26b are viewed from the direction along the axis S without any twist, the arrangement direction of the circle T _{1 and} the arrangement direction of the circle T ₂ are drawn so as to coincide with each other.

As described above, in order to change the TE mode light into the TM mode light, when the left end face 26a and the right end face 26b in the connected state are viewed along the axis S, it is also shown in FIGS. 2 (A) and (B). As shown
The circles T ₁ and T ₂ may be connected so that the axes S are twisted by 90 ° so that the arrangement directions of the circles T ₁ and T ₂ are orthogonal to each other. By connecting in this way, the TE mode light is changed to the TM mode light and the TM mode light is changed to the TE mode light.

(Explanation of Configuration of Optical Switch Element) FIG. 3 is a diagram showing an example of the configuration of an optical switch element suitable for use in the control optical switch of this embodiment. The control optical switch 20 indicated by a white circle in FIG. For example, the configuration in which the inversion Δβ directional coupling type 2 × 2 optical switching element 21 is shown in more detail.

In the figure, reference numerals 30 and 32 denote input / output waveguides, where the left ends of the respective waveguides 30 and 32 are input ports 30a and 32a and the right ends thereof are output ports 30b and 32b. The waveguides 30 and 32 are close to each other in the optical coupling region 34 so that they are parallel to each other.
It is provided in 12. The waveguides 30 and 32 are formed, for example, on the substrate 12 by Ti
Are formed by diffusing. Furthermore, the optical coupling area
Control electrodes 36a and 36b, which are divided into, for example, two pieces in order from the input port 30a side to the waveguide 30 of 34, are similarly provided in the optical coupling region 34.
In the waveguide 32, control electrodes 38a and 38b, which are divided into two, for example, are sequentially provided from the input port 32a side.

The above-mentioned input / output waveguides 30, 32 and control electrodes 36a, 36b, 38
In the optical switch element 21 including a and 38b, the control electrodes 36a and 38b have a voltage of positive (+) polarity and the control electrodes 36b and 3b.
By applying a voltage of negative (-) polarity to 8a and causing light to interact between the waveguides 30 and 32 of the optical coupling region 34 (by so-called inversion Δβ operation), light can be switched. .

When the optical switch element 21 is configured to operate in any of the Cross and Bar states for TM waves, and configured to operate only in the Cross state for TM waves, for example, as follows: It suffices to make a connection with the input / output waveguide. As shown in FIG. 1, in both cases of the first group I and the second group II, the input port 32a and the output port 30b of the optical switch element 21 are connected to the input / output waveguide 14, respectively,
Further, the output port 32b of the optical switching element 21 of the first group I,
The input port 30a of the optical switch element 21 of the second group II is connected. Incidentally, the connection of the optical switch 21 can be arbitrarily changed depending on how the element 21 is configured to operate.

FIG. 4 shows the Δβ directional coupling type optical switching element described above.
FIG. 21 is an operating condition diagram ((L / l _c ) − (ΔβL / π) diagram) of 21 and shows L / l _{c on the} horizontal axis and ΔβL / π on the vertical axis (where L is the element length. , L _c is the bond length, Δβ is the propagation constant difference, and π is the circular constant). In the optical switch element 21,
Since the operating voltage applied to TM wave and TE wave is equal,
In FIG. 4, the values of ΔβL / π generated for the TM wave and the TE wave when the operating voltages are the same are shown on the same scale on the vertical axis. TM
The value of ΔβL / π that occurs with respect to the wave is written without enclosing it in parentheses.
The value of ΔβL / π generated for the wave is shown in parentheses.

In the figure, the hatched area P surrounded by the solid line is TM
The figure shows a region where the optical switch element 21 operates in the Bar state with respect to mode light (TM wave), and operates with crosstalk of -20 dB or less which is practically desirable. The hatched area Q surrounded by the solid line is the optical switching element 21 for the TM wave.
However, it works in the Cross state, and it is practically desirable -20 dB
The following shows the region that operates with crosstalk.

Similarly, the hatched areas R and S surrounded by broken lines are
For TE mode light (TE wave), the optical switch element 21
Operates in r state and Cross state, and is desirable for practical use −
It shows the region that operates with crosstalk of 20 dB or less.

In the inversion Δβ directional coupling type optical switching element 21, when the absolute value of the voltage (operating voltage) applied to the control electrodes 36a, 36b, 38a, 38b is increased or decreased, the refractive index for the TM wave and the TE wave changes, The propagation constant difference Δβ for the TM wave and the TE wave changes according to the amount of change in the refractive index. If the wavelength is represented by λ and the refractive index change amount is represented by Δn, then Δβ = (2π / λ) · Δ
n.

When the refractive index change amount Δn for the TM wave is generated so that ΔβL / π for the TM wave is set to a certain value C1, the optical switch element 21 operates in the Cross state for the TM wave. Here, L and l _c are constants that are arbitrarily determined in terms of design, π is the circular constant, and Δβ changes by changing Δn.
Also, in order to set ΔβL / π for TM wave to a certain value C2, TM
When the refractive index change amount Δn with respect to the wave is generated, the optical switch element 21 operates in the Bar state with respect to the TM wave. The regions P and Q related to the TM wave are regions obtained by setting the numerical range of the values C1 and C2 as the numerical range in which the crosstalk is −20 dB or less.

Similarly, ΔβL / π for TE wave is the same value as for TM wave.
When the refractive index change amount Δn for the TE wave is generated as indicated by C1, the optical switch element 21 operates in the Bar state for the TE wave. When the refractive index change amount Δn for the TE wave is generated so that ΔβL / π for the TE wave has the same value C2 as that for the TE wave, the optical switch element 21 operates in the Bar state for the TE wave. Areas R and S in FIG. 4 related to the TE wave are values C1
The range obtained by setting the numerical ranges of C2 and C2 as the numerical range in which the crosstalk is −20 dB or less.

Further, in the optical switch element 21, the operating voltage for the TM wave having a large electro-optic effect and the TE voltage having a small electro-optic effect are used.
The operating voltage for the waves is the same. It is known that when the operating voltage is the same, (refractive index change amount Δn for TM wave) ≈ (refractive index change amount Δn for TE wave) × 3.3. Therefore, since Δβ = (2π / λ) · Δn as described above, when the same operating voltage is applied to the TM wave and TE wave (ΔβL / π generated for the TM wave) ≒ (for the TE wave The resulting ΔβL / π) is 3.3.

Thus, in the optical switch element 21, the TM wave and the TE wave are
Since the same operating voltage is applied to the waves (ΔβL / π generated for TM waves) ≒ (ΔβL / π generated for TE waves) × 3.3, the operating condition diagram in Fig. 4 focuses on this point. Has been created. That is, on the vertical axis of FIG. 4, the value of ΔβL / π generated for TM wave and TE wave when the operating voltage is the same,
Regions P, Q, R and S are shown on the same scale, and the vertical axis is scaled in this way.

In the vertical axis of FIG. 4, the value of ΔβL / π for TM wave is 2 × 3.3 and ΔβL / for TE wave is
The same scale is used for the π value of 2, and the same vertical scale is used for the TM wave to obtain a ΔβL / π value of 4 × 3.3 and the TE wave for the ΔβL / π value of 4. There is.

As can be understood from the operating condition diagram of Fig. 4 created in this way, the operating state for TM waves changes from the Cross state to the Bar state.
Even if the operating voltage is changed to switch to the state or from the Bar state to the Cross state, the TE wave is substantially
An optical switch element 21 that operates only in the Bar state can be created, and the setting conditions for such an optical switch element 21 are as follows.
It can be easily determined based on the operating condition diagram shown in FIG.

Next, referring to FIG. 5, the design conditions of the optical switch element 21 will be described in more detail.

5 (A) and 5 (B) are partially enlarged views of the operation condition diagram shown in FIG. In these figures, S
_TE and _S'TE indicate the allowable range of _{manufacturing} error, and in the example shown in the figure, S
_TE is within the range of design value ± (design value × 0.375),
_S'TE is within the range of design value ± (design value x 0.5). Similar to FIG. 4, also in FIG. 5, the values of ΔβL / π generated for the TM wave and the TE wave when the operating voltages are equal are shown on the same scale on the vertical axis, and for the TM wave. The value of ΔβL / π generated is shown without being enclosed in parentheses, and the value of ΔβL / π produced for the TE wave is also shown enclosed in parentheses.

In the region between the curves L ₁ and L ₂ indicated by the broken line, the optical switching element 21 is in the Cross state with respect to the TE wave, and the loss is 0.4
A region operating so as to be 5 dB or less (that is, crosstalk is -10 dB or less), similarly, curves M ₁ and M ₂ indicated by broken lines
The region between is the region where the optical switching element 21 is in the Bar state with respect to the TE wave and operates so that the loss is 0.45 dB or less (that is, the crosstalk is -10 dB or less).

As shown in FIG. 5 (A), for example, L /
It is assumed that the optical switch element 21 is prepared such that l _c is L / l _c = 2 and the value of L / l _c for the TE wave is in the range of S _TE shown in the figure. In such a case, even if the operating voltage is increased or decreased to switch the operating state for the TM wave, the optical switching element 21 operates substantially only for the TE wave in the Cross state.

Further, for example, the optical switching element 21 is arranged so that L / l _c for the TM wave becomes L / l _c = 2 and the value of L / l _c for the TE wave becomes a value in the range of S ′ _TE shown in the figure. If it was created,
Even if the operating voltage is increased / decreased, the optical switching element 21 operates substantially only for the TE wave in the Bar state.

In the optical switch element 21 created in this way,
As is clear from FIG. 5 (A), the value of ΔβL / π is a
When the operating voltage is applied so that the value is in the range of −a ′ or bb ′, it is in the Bar state or the Cross state for the TM wave, and the crosstalk is approximately −20 dB or less. It can be understood that it works as follows.

Moreover, when such an operating voltage is applied, it can be operated so that it is in a Bar state or a Cross state for TE waves, and that the crosstalk is approximately -10 dB or less. These crosstalk values are practically satisfactory.

Similarly, as shown in FIG. 5 (B), for example, L / l _c for TM wave is L / l _c = 2.7, and L / l _c for TE wave is
If the optical switch element 21 is made so that the value of S is in the range of S _TE or S ′ _TE , the optical switch element 21 that operates with a crosstalk that is practically satisfactory, as described above. Can be obtained.

As can be understood from FIGS. 5 (A) and 5 (B), even if the value of L / l _c for the TM wave is changed from 2 to 2.7, S
_{The TE} and _S'TE ranges do not move much. This is a gentle preparation condition such that L / l _c for TM wave is in the range of 2 to 2.7 and L / l _c for TE wave is in the range of S _TE or S ′ _TE. It means that the optical switch element 21 that operates with crosstalk that is practically satisfactory can be manufactured with high yield. Therefore, by using, for example, the inverted Δβ directional coupling type optical switch element 21 as the control optical switch 20, the front-stage switch 10 and the rear-stage switch 24 having practical crosstalk characteristics can be produced with good yield under mild production conditions. Can be done.

(Operation Example) FIGS. 6A and 6B are explanatory views of an operation example of this embodiment. In the following description, the control switch 20 is configured with the optical switching element 21, and the optical switching element 21 selectively operates in the Bar or Cross state in response to the operating voltage for the TM wave to generate the TE wave. On the other hand, the case where it is created so that it operates only in the Cross state regardless of the operating voltage will be described. Further, in the following description, two polarization components X and Y of the signal light which are orthogonal to each other, and the polarization component X which is the TM wave in the front stage switch 10 is one light X, and the TE component in the front stage switch 10. The polarization component Y which is is referred to as the other light Y.

As shown in FIG. 6 (A), for example, one light X and the other light Y are input from the input port 161, and the output port 183 is input.
In the case of outputting from the first input / output waveguide 141, the propagation path of one light X input as the TM wave is controlled by the control switch 20 of the front stage switch 10 to input / output the first row input / output waveguide 141 to the third row input / output. The input / output waveguide 143 is changed to the input / output waveguide 143 in the third row of the post-stage switch 24.
Input 3 '. The one light X is converted from the TM wave to the TE wave by the polarization changing means 26 and input to the input / output waveguide 143 '. Therefore, the propagation path is not controlled by the post-stage switch 24 and goes straight through the input / output waveguide 143'. And output from the output port 183. On the other hand, the other light Y input to the front stage switch 10 as a TE wave does not control its propagation path in the front stage switch 10 and goes straight through the input / output waveguide 141, and goes straight to the input / output waveguide of the first row of the rear stage switch 24. Input to 141 '. The other light Y
Is converted from the TE wave to the TM wave by the bias changing means 26 and input to the post-stage switch 24. Therefore, by controlling the propagation path thereof by the control switch 20 of the post-stage switch 24, input / output from the input / output waveguide 141 ′ is performed. It can be changed to the waveguide 143 'and output from the output port 183.

A leak light X ₁ generated when _one light X passes through the control switch 20 of the rear stage switch 24 as a TE wave and the other light Y is TE light.
The leaked light Y ₁ generated when passing through the control switch 20 of the front stage switch 10 as a wave is small, and the leaked lights ₁ and Y ₁ are also the input / output waveguides 143 ′ and 1 as shown in the figure.
Since it does not mix into 43 and escapes to the substrate 12, there is no practical problem.

Further, as shown in FIG. 6 (B), for example, when one light X and the other light Y are input from the input port 161, and output from the output port 181, the propagation path of the light X is set to the previous stage. By controlling the control switch 20 of the switch 10, the input / output waveguide 141 of the first row goes straight, and the input / output waveguide 141 is input to the input / output waveguide 141 ′ of the post-stage switch 24. One light X is converted from the TM wave into the TE wave by the polarization changing means 26 and input to the input / output waveguide 141 ', so that the propagation path is not controlled by the post-stage optical switch 24 and the input / output waveguide 141' is changed. It goes straight and is output from the output port 181. On the other hand, the other light Y goes straight through the input / output waveguide 141 without being controlled in its propagation path in the front stage switch 10 and is input to the input / output waveguide 141 'of the rear stage switch 24. The other light Y
Is converted from the TE wave to the TM wave by the bias changing means 26 and input to the post-stage switch 24, so that by controlling the propagation path thereof by the control switch 20 of the post-stage switch 24, the input / output waveguide 141 ′ is made to go straight. Can be output from the output port 181.

A leak light X ₁ generated when _one light X passes through the control switch 20 of the rear stage switch 24 as a TE wave and the other light Y is TE light.
The leaked light Y ₁ generated when passing through the control switch 20 of the front stage switch 10 as a wave is small, and the leaked lights X ₁ and Y ₁ are input / output waveguides 141 ′ and 1 as shown in the figure.
Since it does not mix into 43 and escapes to the substrate 12, there is no practical problem. The leakage lights X ₁ and Y ₁ are generated because the TE wave is not controlled by the control switch 20.

In the above-described embodiment, the input / output waveguides 14 having the same row numbers of the front stage switch 10 and the rear stage switch 24, for example, the input / output waveguides 141 and 141 ′ are connected in a one-to-one correspondence. , 24 different row number input / output waveguides
14 The comrades may be connected in a one-to-one correspondence. For example, by setting the connection relationship between the front-stage switch 10 and the rear-stage switch 24 and the operating state of the control switch 20 for the TM wave and the TE wave arbitrarily and appropriately,
It is possible to selectively output the light (input signal) X and Y input from 1, 162 from any one of the output ports 181, 182, 183, 184.

Second Example (Explanation of Overall Configuration) In the second example, an example in which the front-stage and rear-stage optical matrix switches are crossbar type optical matrix switches will be described.

FIG. 7 is a plan view schematically showing the constitution of the second embodiment. The constituents corresponding to those of the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted.

In the figure, reference numeral 40 denotes an optical matrix switch device. The optical matrix switch device 40 includes a crossbar type front stage optical matrix switch 42 and rear stage optical matrix switch 44, and these front stage switch 42 and rear stage switch 44.
And a bias changing means 26 for connecting in series.

The front stage switch 42 and the rear stage switch 44 are configured by using the ferroelectric crystal substrate 12.

The pre-stage switch 42 includes a substrate 12, two input / output waveguides 46 in the row direction and two input / output waveguides 48 in the column direction, which are provided on the substrate 12, respectively, at the intersections of the waveguides 46 and 48, respectively. It consists of four control light switches 20 provided. The control switch elements 20 are arranged in 2 rows and 2 columns. Rear switch
Similarly to the pre-stage switch 42, the 44 also includes the substrate 12, two input / output waveguides 46, two input / output waveguides 48, and four control switches 20. In the drawing, the left and right ends of the input / output waveguide 46 are indicated by reference numerals 50 and 52, and the upper and lower ends of the input / output waveguide 48 are indicated by reference numerals 54 and 56.

In the latter-stage switch 44, a leakage light elimination means 58, for example, a TE wave transmission type polarization filter is provided in the input / output waveguide 48 between the upper end 54 of the output waveguide 48 and the control switch 20 in the first row. As the polarizing filter, various well-known structures may be used. Further, as the leaked light eliminating means 58, conventionally known mode filters having various structures may be used. The leakage light excluding means 58 may be arranged on any suitable propagation path capable of excluding the leaking light. For example, the TM wave transmitting type leaking light excluding means 58 may be provided at the upper end 54 of the output waveguide 48 in the front stage switch 42. And the control switch 20 of the first row may be arranged in the input / output waveguide 48.

In addition, the right end 52 of the input / output waveguide 46 of the front stage switch 42,
The left end 50 of the input / output waveguide 46 of the rear stage switch 44 is connected so as to connect the input / output waveguide 46 of the same row number. The connection of these input / output waveguides 46 is similar to that of the first embodiment.
Is carried out through the bias changing means 26 in the state of being twisted by 90 °.
Similarly, the upper end 54 of the input / output waveguide 48 of the front stage switch 42 is
And the upper end 54 of the input / output waveguide 48 of the rear-stage switch 44 are connected via the bias changing means 26 in which the shaft S is twisted by 90 °. In this case, the input / output waveguides 48 having the same column number are connected.

In this way, the front stage switch 42 and the rear stage switch 44 are connected in series.

In this embodiment, the left end 50 of the input / output waveguide 46 of the front stage switch 42 is connected to the input port 50 of the optical matrix switch device 40.
1, 502, and the lower end 56 of the input / output waveguide 48 of the post-stage switch 44.
Are output ports 561 and 562 of the optical matrix switch device 40.

Also in the second embodiment configured as described above, the same effect as the first embodiment can be obtained.

(Example of Operation) FIG. 8 is an explanatory diagram of an example of the operation of this embodiment. In the following description, the control optical switch is configured by the optical switch element 21, and the optical switch element 21 selectively operates in the Bar or Cross state according to the operating voltage for the TM wave to generate the TE wave. On the other hand, the case where it is created so that it operates only in the Cross state regardless of the operating voltage will be described. Further, in the following description, two polarization components X and Y of the signal light which are orthogonal to each other, and the polarization component X which is the TM wave in the front stage switch 10 is one light X, and the TE component in the front stage switch 10. The polarization component Y which is is referred to as the other light Y.

As shown in FIG. 8, for example, when one light X and the other light Y are input from the input port 461 and output from the output port 482, the propagation path of the one light X input as the TM wave. Is controlled by the control switch 20 of the front-stage switch 42 to change the second input / output waveguide 461 from the second input / output waveguide 461.
Change to the input / output waveguide 482 of the row, and this input / output waveguide 482
To the second row input / output waveguide 482 'of the rear stage switch 44. The one light X is converted from the TM wave to the TE wave by the polarization changing means 26 and input to the input / output waveguide 482 '. It goes straight and is output from the output port 562. On the other hand, the other light Y input to the front stage switch 42 as a TE wave goes straight through the input / output waveguide 461 without its propagation path being controlled by the front stage switch 42 and goes straight to the input / output waveguide of the first row of the rear stage switch 44. 461 'is input. The other light Y is converted from the TE wave to the TM wave by the bias changing means 26 and input to the post-stage switch 44, so that its propagation path is changed to the post-stage switch.
By controlling the control switch 20 of 44, the input / output waveguides 461 'and 482' can be moved straight and output from the output port 562.

The leak light X ₁ generated when _one light X passes through the control switch 20 of the rear stage switch 44 as a TE wave and the other light Y is TE light.
Any leakage light Y ₁ that occurs when passing through the control switch 20 of the preceding stage switch 42 as a wave is slight. In addition, the leaked light Y ₁ is transmitted from the input / output waveguides 481, 482 to the input / output waveguide 48
When propagating to 1 ′ and 482 ′, the leak light excluding means 58 transmits only the TE wave, so the leak light Y ₁ converted to the TM wave is removed. The leaked light Y ₁ escapes to the substrate 12 through the leaked light excluding means 58.

The connection relationship between the front stage switch 42 and the rear stage switch 44, TM
Light (input signals) X and Y input from the input ports 501 and 502 are output to the output ports 561 and 5 by setting the operating state of the control switch 20 for waves and TE waves arbitrarily and appropriately.
It can be selectively output from any of the 62 output ports.

Third Embodiment (Explanation of Overall Configuration) In the third embodiment, an example in which the optical matrix switches in the front stage and the rear stage are simplified optical matrix switches will be described. In this embodiment, Japanese Patent Application No. 61-
One of the embodiments of the invention proposed in 267700 was applied to the optical matrix switch which is a constituent of the first invention.

FIG. 9 is a plan view schematically showing the constitution of the third embodiment. The constituents corresponding to those of the first and second embodiments described above are designated by the same reference numerals, and detailed description thereof will be omitted.

In the figure, reference numeral 60 denotes an optical matrix switch device, and this optical matrix switch device 60 includes a simplified tree-structured front stage optical matrix switch 62 and rear stage optical matrix switch 64, and these front stage switch 62 and rear stage switch 64. And a bias changing means 26 connected in series.

The front stage switch 62 and the rear stage switch 64 are configured by using the ferroelectric crystal substrate 12.

The front stage switch 42 includes a substrate 12, a 1 × 2 input side control optical switch 66 and a 2 × 1 output side control optical switch 68, and a 2 × 2 control optical switch 70 for connecting these switches 66 and 68. It has a tree structure in which all the output side optical switches 68 are connected to one input side optical switch 66 via the 2 × 2 optical switch 70. In order to configure the front-stage switch 62, for example, the above-mentioned inverted Δβ directional coupling type 2 × 2 optical switch element 21 is used as a 1 × 2 input side optical switch 66, 2 × 1 output side optical switch 68 and 2 × 2 optical switch. Used as the switch 70.

As shown in the figure, in this embodiment, the switches 66, 6
8 and 70 are provided on each of the four substrates 12, for example, these switches 6
Arrange 6, 68 and 70 in 4 rows and 3 columns and connect as described below. That is, the input side optical switches of the first and second rows
66 is connected to both the optical switches 70 of the first and second rows, respectively, and the input side optical switches of the third and fourth rows are similarly connected.
66 are connected to both the third and fourth row optical switches 70, respectively. Then, the optical switches 70 of the first and third rows
To the output side optical switches 68 of the first and third rows, respectively, and the optical switches 70 of the second and fourth rows, respectively, of the output side optical switches 68 of the second and fourth rows, respectively. Connect to both sides. The switches 66, 68 and 70 are connected via the waveguide 72.

Similarly to the front-stage switch 62, the rear-stage switch 64 also includes the substrate 12 and the optical switches 66, 68, and 70.

Further, the front-stage switch 62 and the rear-stage switch 64 are connected in series via the bias changing means 26 so that, for example, the output-side optical switch 68 of the front-stage switch 62 and the input-side optical switch 66 of the rear-stage switch 64 of the same row number are connected. Connecting. This connection is made through the bias changing means 26 in which the shaft S is twisted by 90 °.

The input side optical switch 66 of the front stage switch 62 is respectively to the input ports 741, 742, 743, 744 of the device 60, and the output side optical switch 68 of the rear stage switch 64 is respectively the output ports 761, 762, 763 of the device 60. Connected to the 764.

Then, the TM wave transmission type leak light eliminating means 58 is provided on an arbitrary and suitable leak light propagation path. In the case of the illustrated example, between the first row optical switch 20 and the third row optical switch 68, between the second row optical switch 20 and the fourth row optical switch 68, and between the third row optical switch 20 and the third row optical switch 68. They are provided between the optical switches 68 in the first row and between the optical switches 20 in the fourth row and the optical switches 68 in the second row. The leakage light elimination means 58 does not necessarily have to be provided.

Also in the third embodiment configured as described above, the same effect as the same embodiment can be obtained.

(Example of Operation) FIG. 10 is an explanatory diagram of an example of the operation of this embodiment. In the following description, for example, optical switches 66, 68, 70 configured using the optical switch element 21 selectively operate in the Bar or Cross state according to the operating voltage for TM waves and for TE waves. In the following, the case where it is created so that it operates only in the Cross state regardless of the operating voltage will be described. Further, in the following description, two polarization components X and Y of the signal light which are orthogonal to each other, and the polarization component X which is the TM wave in the front stage switch 10 is one light X, and the TE component in the front stage switch 10. The polarization component Y which is is referred to as the other light Y.

As shown in FIG. 10, for example, when one light X and the other light Y are input from the input port 741 and output from the output port 763, the propagation path of the one light X input as the TM wave is obtained. Is controlled by the optical switches 66 and 70 of the front stage switch 62 to propagate one light X from the input side optical switch 66 of the first row to the output side optical switch 68 of the third row,
The input side optical switch 68 of the front stage switch 62 is made to input to the input side optical switch 66 of the third row of the rear stage switch 64. One light X is converted from the TM wave to the TE wave by the polarization changing means 26 and is input to the input side optical switch 66 of the rear stage switch 64. Therefore, the propagation path of the rear stage switch 64 is not controlled and goes straight to the third stage. Input to the output side optical switch 68 of the row. Then, it is output from the output port 763 via the output port side optical switch 68. On the other hand, as TE wave, the front switch 6
The other light Y input to 2 goes straight without its propagation path being controlled by the front stage switch 62, and thus is input from the input side optical switch 66 of the first row to the output side optical switch 68 of the first row, And the optical switch 68 on the output side of the front stage switch 62
Is input to the input side optical switch 66 in the first row of the rear stage switch 64. The other light Y is converted from the TE wave to the TM wave by the bias changing means 26 and is input to the post-stage switch 64.
By controlling the propagation path by the optical switches 66 and 70 of the post-stage switch 64, the input side optical switch of the first row
Input from 66 to the output side optical switch 68 in the third row. The other light Y passes through the output side optical switch 68,
Output from output port 763.

One optical X is a TE wave and is an optical switch of the rear stage switch 64.
The leaked light X ₁ generated when passing through 70 and the leaked light Y ₁ generated when the other light Y passes through the optical switch 70 of the pre-stage switch 62 as a TE wave are the leaked light excluding means 58 that transmits only the TM wave. Therefore, the leaked lights X ₁ and Y ₁ which are TE waves are removed. The leaked lights X ₁ and Y ₁ escape to the substrate 12 via the leaked light excluding means 58. Further, in the four propagation paths in the straight traveling direction (for example, the propagation path from the input port 741 to the output port 761),
When leak light is going to be mixed from one propagation path to the other propagation path in any two straight traveling directions, it is necessary to pass through two control optical switches. Yes, so there is almost no crosstalk between these two arbitrary propagation paths.

Connection relationship between the front stage switch 62 and the rear stage switch 64, TM
Input port 74 by arbitrarily setting the operating states of the control optical switches 66, 68, 70 for waves and TE waves.
Light (input signals) X and Y input from 1, 742, 743, and 744 can be selectively output from any one of the output ports 761, 762, 763, and 764.

Modified Example of Third Embodiment FIG. 11 is an explanatory view of a modified example of the optical matrix switches at the front stage and the rear stage in the third embodiment, and schematically shows the configuration thereof. In this modification, one of the embodiments of the invention proposed in Japanese Patent Application No. 61-267700 is applied to the front and rear optical matrix switches.

In the figure, reference numeral 74 is an optical matrix switch, which is configured using the ferroelectric crystal substrate 12. The optical matrix switch 74 is used as an optical matrix switch in the front and rear stages.

The optical matrix switch 74 includes a 1 × 2 input side control optical switch 76 provided on the input side of the switch 74, a 2 × 1 output side control optical switch 78 provided on the output side, and these switches.
It comprises a 4 × 4 unit matrix control switch 80 provided between 76 and 78. All output side optical switches 78 are unit trix switches for one input side optical switch 76.
It has a tree structure such that it is connected via 80. The input side optical switch 76 is connected to the input port 82 of the switch 74 and the output side optical switch 78 is connected to the output port 84 of the switch 74, respectively, from one arbitrarily selected input port 82 to all the output ports 84. A light propagation path is formed.

The unit matrix switch 80 is similar to the 4 × 4 optical matrix switches 62 and 64 shown in FIG.
The unit matrix switch 80 is composed of the 2 × 2 optical switch 70 and the output side optical switch 68, and two unit matrix switches 80 form one group p. The input ports 82 form a group q of four ports each. Output side optical switch 78 is 8
One set constitutes a group r.

The propagation path of the light input to one of the input ports 82 of the group p is branched into two by the input side optical switch 76 and connected to the two unit matrix switches 80 of the group q. The unit matrix switch 80 branches into eight, and the eight branched propagation paths are respectively connected to eight output ports 84 via the output side optical switch 78 of the group r.

The optical matrix switch 74 of this embodiment includes two groups p, two groups q, and one group r, and the output side optical switches 78 of one group r are redundantly used to form the group p. Propagation paths are formed from any of the input ports to the eight output ports.

The output ports of the optical matrix switch 74 used as the optical matrix switch in the previous stage are associated with the input ports of the optical matrix switch 74 used as the optical matrix switch in the subsequent stage in a one-to-one correspondence, and are connected via the polarization polarization means. Thus, the optical matrix switch device of the first invention may be configured.

<Second Invention> First Embodiment Hereinafter, the configuration of a first embodiment of the second invention will be schematically described with reference to FIG.

The optical matrix switch device 28 of this embodiment is configured by using the compound semiconductor crystal substrate 12, and the polarization of the electro-optic effect having a polarization direction orthogonal to each other and the polarization of the electro-optic effect having a small polarization are input. An optical matrix switch (hereinafter simply referred to as a front stage switch) 10 and a compound semiconductor crystal substrate 12 are used to input polarized light having a large electro-optical effect and polarized light having a small electro-optical effect, which have polarization directions orthogonal to each other. The following optical matrix switch (hereinafter, simply referred to as a rear switch) 24 to be connected, and the front switch 10 and the rear switch 24 are connected in series,
The polarized light output from the control light switch 20 of the front stage switch 10 is rotated by 90 ° and is input to the control light switch 20 of the rear stage switch 24.

Then, the control optical switch 20 of the front-stage switch 10 and the rear-stage switch 24 is selectively operated in a bar state (Bar state) or a cross state (Cross state) with respect to polarized light having a large electro-optical effect, and is electrically operated. For polarized light with a small optical effect, it is an optical switch that operates non-selectively in one of the bar state (Bar state) and cross state (Cross state). Here, that the electro-optical effect is small has a meaning including a case where the electro-optical effect is substantially absent.

In this embodiment, in order to configure the pre-stage switch 10, for example, a GaAs substrate is prepared as the compound semiconductor crystal substrate 12,
For example, a Ridge type input / output waveguide 1 is provided on the substrate 12.
4 are formed, and two control optical switches 20 are provided in each input / output waveguide 14.

Then, the control switches 20 are divided into a first group I and a second group II, and the control switches 20 of the first group I and the second group II are grouped.
The control switch 20 is connected via the communication waveguide 22.
As shown in the figure, the control switches 20 provided in the same row of the first group I and the control switches 20 selected so as not to overlap one by one from each row of the second group II are associated one to one. And connect.

The pre-stage switch 10 includes the substrate 12 configured as described above,
It is composed of an input / output waveguide 14, a control switch 20, and a communication waveguide 22. The rear switch 24 also has the same board as the front switch 10.
12, input / output waveguide 14, optical switch element 20 and connecting waveguide
Consists of 22.

In the optical matrix switch device 28 of this embodiment, the right end 18 of the input / output waveguide of the front stage switch 10 and the left end 16 of the input / output waveguide of the rear stage switch 24 are biased in one-to-one correspondence. Each is connected by means 26. Then, the left end 161 of the input / output waveguide 14 in the front stage switch 10
, 162 as input ports of the optical matrix switch device 28, and right ends 183 and 184 of the input / output waveguides 14 in the post-stage switch 24 as output ports of the optical matrix switch device 28.

The connection relationship of each component in the optical matrix switch device 28 of the first embodiment configured as described above is as follows.
This is the same as the first embodiment of the first invention, and therefore the light propagation path in the optical matrix switch device 28 of the first embodiment is formed similarly to the first embodiment of the first invention.

It is known that when a GaAs substrate is used as the compound semiconductor crystal substrate 12, the polarized light having a large electro-optical effect is a TE wave and the polarized light having a small electro-optical effect is a TM wave.
Therefore, for the TE wave input to the front stage switch 10,
After selectively changing its propagation path in the front-stage switch 10 and converting the TM wave input to the front-stage switch 10 into a TE wave by rotating the deviation direction by 90 ° by the deviation changing means 26. By selectively changing the propagation path in the post-stage switch 24, even when a GaAs substrate is used as the compound semiconductor crystal substrate 12, a switching operation without polarization dependence is realized by utilizing the electro-optic effect. it can.

Here, two polarization components X of the signal light, which are orthogonal to each other,
Y, and the polarization component X, which is a TE wave in the front stage switch 10, is converted into one light X, and in the front stage switch 10, TM
If the polarization component Y which is a wave is expressed as the other light Y, in the optical matrix switch device 28 configured as described above,
One light X and the other light Y are input from the front stage switch 10 to the rear stage switch 24 via the deviation changing means 26.

Therefore, one light X propagates in a TE wave state having a large electro-optical effect when propagating in the front-stage switch 10 and in a TM wave state having a small electro-optical effect when propagating in the rear-stage switch 24. To do. The other light Y is the front switch
When propagating in 10, it propagates in the state of a TM wave having a small electro-optical effect, and when propagating in the post-stage switch 24, it propagates in a state of a TE wave having a large electro-optical effect.

The control optical switch 20 that constitutes the front-stage switch 10 and the rear-stage switch 24 is a TE having a large electro-optical effect.
For waves, it operates selectively in the Bar state or Cross state. Therefore, for one light X, the control light switch 20 of the front stage switch 10 can selectively change the propagation path by utilizing the electro-optic effect, and for the other light Y, the control light of the rear stage switch 24 can be used. The switch 20 allows the propagation path to be selectively changed by utilizing the electro-optic effect.

Therefore, the compound semiconductor crystal substrate 12 is used to
Even when the 10 and the latter stage switch 24 are configured, one of the light X and the other light Y has a large electro-optical effect.
Since the propagation path can be selectively changed in the TE wave state, it is possible to realize switching operation without polarization dependence by utilizing the electro-optic effect.

Moreover, the control optical switch 20 that constitutes the front-stage switch 10 and the rear-stage switch 24 are both TM with a small electro-optical effect.
For waves, it operates non-selectively in either the Bar state or the Cross state. Therefore, for one light X, the control light switch 20 of the latter switch 24 can provide a fixed propagation path connecting between the specific input / output ports of the latter switch 24, and for the other light Y. Is a control optical switch 20 of the front stage switch 10
A fixed propagation path can be provided that connects between 10 specific input / output ports.

Therefore, by selectively changing the propagation path of one light X in the front stage switch 10, a propagation path connecting desired input / output ports of the optical matrix switch device 28 can be formed for one light X. Further, by selectively changing the propagation path of the other light Y in the post-stage switch 24, the propagation path connecting the desired input / output ports of the optical matrix switch device 28 can be formed for the other light Y.

The configuration of the control light switch 20 is not limited, but it is preferable to use, as the control light switch 20, an optical switch having a control electrode of a single electrode type or an inverted Δβ electrode type.

Further, in the above-described embodiment, since the GaAs substrate is used as the compound semiconductor crystal substrate 12, the polarized light having a large electro-optical effect is the TE wave and the polarized light having a small electro-optical effect is the TM wave, so that the control optical switch 20 is used. , Selective operation for TE wave in Cross state or Bar state, and Cross for TM wave
Although the optical switch that operates non-selectively in either the state or the bar state is created, the control optical switch 20
The operating conditions and the production conditions may be arbitrarily changed according to the substrate material.

Second Embodiment Hereinafter, a configuration of a second embodiment of the second invention will be schematically described with reference to FIG.

The optical matrix switch device 40 according to the second embodiment includes a pre-stage switch 4 including a compound semiconductor crystal substrate 12.
2. The post-stage switch 44 and the bias changing means 26 configured by using the compound semiconductor crystal substrate 12.

The pre-stage switch 42 includes a substrate 12, two input / output waveguides 46 in the row direction and two input / output waveguides 48 in the column direction, which are provided on the substrate 12, respectively, at the intersections of the waveguides 46 and 48, respectively. It is composed of four control light switches 20 provided and has a crossbar type configuration. Similarly to the front stage switch 42, the rear stage switch 44 also includes the substrate 12, two input / output waveguides 46, two input / output waveguides 48, and four control optical switches 20,
It has a crossbar type configuration. For example, a ridge type waveguide is used as the waveguide.

In the latter-stage switch 44, a leakage light elimination means 58, for example, a TM wave transmission type polarization filter is provided in the input / output waveguide 48 between the upper end 54 of the output waveguide 48 and the control switch 20 in the first row. As the polarizing filter, various conventionally known ones may be used. Further, various conventionally known mode filters may be used as the leaked light eliminating means 58. The leakage light excluding means 58 may be arranged at any suitable position on the propagation path of light that can eliminate the leakage light. For example, TE wave transmission type leak light elimination means 58
The upper end 54 of the output waveguide 48 in the front stage switch 42 and the first
It may be arranged between the row control switch 20 and the input / output waveguide 48.

The front stage switch 42 and the rear stage switch 44 are connected in series via the bias changing means 26 in a state where the shaft S is twisted by 90 °.

The left end 50 of the input / output waveguide 46 of the front stage switch 42 is used as the input ports 501 and 502 of the optical matrix switch device 40, and the lower end 56 of the input / output waveguide 48 of the rear stage switch 44 is used as the output port 561 of the optical matrix switch device 40. , 562.

The connection relationship of each component in the optical matrix switch device 40 of the second embodiment configured as described above is as follows.
This is the same as the second embodiment of the first invention, and therefore the light propagation path in the optical matrix switch device 40 of the second embodiment is formed similarly to the second embodiment of the first invention.

Also in this embodiment, GaAs is used as the compound semiconductor crystal substrate 12.
A substrate is used. Therefore, the polarized light with a large electro-optical effect is TE
Waves and polarized waves with a small electro-optic effect are TM waves, so the TE switch input to the switch 42 is
In 42, the propagation path is selectively changed, and for the TM wave input to the preceding stage switch 42, the bias changing means
By rotating the bias direction by 90 ° by 26 and converting to TE wave, the propagation path can be selectively changed in the post-stage switch 44, so that the electro-optical effect can be utilized even when the GaAs substrate is used. As a result, switching operation without polarization dependency can be realized.

Here, two polarization components X of the signal light, which are orthogonal to each other,
Y and the polarization component X, which is a TE wave in the front stage switch 42, is transmitted to one light X, and in the front stage switch 42, TM
If the polarization component Y, which is a wave, is expressed as the other light Y, the control optical switch 20 that configures the front-stage switch 42 and the rear-stage switch 44 is a bar for a TE wave having a large electro-optical effect.
Since it selectively operates in the state or the Cross state, the control optical switch 20 of the front stage switch 42 can selectively change the propagation path for one light X by utilizing the electro-optical effect.
Further, for the other light Y, the propagation path can be selectively changed by utilizing the electro-optical effect by the control light switch 20 of the post-stage switch 44.

Therefore, in the front stage switch 42, one light X in the TE wave state and the other light Y in the TM wave state are respectively
Since the propagation path can be selectively changed when the TE wave has a large electro-optical effect, it is possible to realize polarization-independent switching operation by utilizing the electro-optical effect.

Moreover, the control optical switch 20 that constitutes the front-stage switch 42 and the rear-stage switch 44 both have a TM with a small electro-optical effect.
For waves, it operates non-selectively in either the Bar state or the Cross state. Therefore, for one light X, the control optical switch 20 of the latter-stage switch 44 can provide a fixed propagation path connecting between the specific input / output ports of the latter-stage switch 44, and for the other light Y. Is the control optical switch 20 of the front stage switch 42
A fixed propagation path can be provided that connects between 42 specific input / output ports.

Therefore, by selectively changing the propagation path of the one light X in the front stage switch 42, the propagation path connecting the desired input / output ports of the optical matrix switch device 40 can be formed for the one light X. Further, by selectively changing the propagation path of the other light Y in the post-stage switch 44, the propagation path connecting the desired input / output ports of the optical matrix switch device 40 can be formed for the other light Y.

Therefore, by selectively changing the propagation path of the one light X in the front stage switch 42, the propagation path connecting the desired input / output ports of the optical matrix switch device 40 can be formed for the one light X. Further, by selectively changing the propagation path of the other light Y in the post-stage switch 24, the propagation path connecting the desired input / output ports of the optical matrix switch device 40 can be formed for the other light Y.

The configuration of the control light switch 20 is not limited, but it is preferable to use, as the control light switch 20, an optical switch having a control electrode of a single electrode type or an inverted Δβ electrode type.

Further, in the above-described embodiment, since the GaAs substrate is used as the compound semiconductor crystal substrate 12, the polarized light having a large electro-optical effect is the TE wave and the polarized light having a small electro-optical effect is the TM wave, so that the control optical switch 20 is used. , Selective operation for TE wave in Cross state or Bar state, and Cross for TM wave
Although the optical switch that operates non-selectively in either the state or the bar state is created, the control optical switch 20
The operating conditions and the production conditions may be arbitrarily changed according to the substrate material.

Third Embodiment Hereinafter, a configuration of a third embodiment of the second invention will be schematically described with reference to FIG.

The optical matrix switch device 60 according to the third embodiment includes a pre-stage switch 62 configured by using the compound semiconductor crystal substrate 12.
And a post-stage switch 64 configured by using the compound semiconductor crystal substrate 12 and a bias changing means 26. For example, a ridge type waveguide is used as the waveguide.

The front stage switch 62 includes a substrate 12, a 1 × 2 input side control optical switch 66 and a 2 × 1 output side control optical switch 68, and a 2 × 2 control optical switch 70 for connecting these elements 66 and 68.
And a tree structure in which all output side optical switches 68 are connected to one input side optical switch 66 via the 2 × 2 optical switch 70. For example, the inversion Δβ directional coupling type 2 × 2 optical switch element 21 described above is replaced by 1 × 2
Input side optical switch 66, 2 × 1 output side optical switch 68 and 2
A × 2 optical switch 70 may be used, or a single electrode type optical switch may be used as the optical switches 66, 68, 70.

The rear-stage switch 64 also has a tree structure including the substrate 12, switches 66, 68, and 70, similarly to the front-stage switch 62.

The front stage switch 62 and the rear stage switch 64 are connected in series via the bias changing means 26 in a state where the shaft S is twisted by 90 °.

The input side optical switch 66 of the front stage switch 62 is respectively to the input ports 741, 742, 743, 744 of the device 60, and the output side optical switch 68 of the rear stage switch 64 is respectively the output ports 761, 762, 763 of the device 60. Connected to the 764.

Then, the TE wave transmission type leak light elimination means 58 is provided on an arbitrary and suitable leak light propagation path. In the case of the illustrated example, between the first row optical switch 70 and the third row optical switch 68, between the second row optical switch 70 and the fourth row optical switch 68, and between the third row optical switch 70 and the third row optical switch 70. They are provided between the optical switches 68 in the first row and between the optical switches 70 in the fourth row and the optical switches 68 in the second row.

The connection relation of each component in the optical matrix switch device 60 of the third embodiment configured as described above is as follows.
This is the same as the third embodiment of the first invention, and therefore the light propagation path in the optical matrix switch device 60 of the third embodiment is formed similarly to the third embodiment of the first invention.

Also in this embodiment, GaAs is used as the compound semiconductor crystal substrate 12.
A substrate is used. Therefore, the polarized light with a large electro-optical effect is TE
Waves and polarized light with a small electro-optic effect are TM waves, so the TE switch input to the switch 62 is not
In 62, the propagation path is selectively changed, and for the TM wave input to the front stage switch 62, bias changing means
If the bias direction is selectively changed in the post-stage switch 64 after the bias direction is rotated 90 ° by 26 to convert it to TE wave, the electro-optical effect can be utilized even when the GaAs substrate is used. As a result, switching operation without polarization dependency can be realized.

Here, two polarization components X of the signal light, which are orthogonal to each other,
Y and the polarization component X, which is a TE wave in the front stage switch 62, is transmitted to one light X, and in the front stage switch 62, TM
If the polarization component Y, which is a wave, is expressed as the other light Y, the control optical switch 20 that configures the front-stage switch 62 and the rear-stage switch 64 is a bar for a TE wave having a large electro-optical effect.
Since it selectively operates in the state or the Cross state, the control optical switch 20 of the front stage switch 62 can selectively change the propagation path for one light X using the electro-optical effect.
Moreover, for the other light Y, the propagation path can be selectively changed by utilizing the electro-optical effect by the control light switch 20 of the post-stage switch 64.

Therefore, in the front stage switch 62, one light X in the TE wave state and the other light Y in the TM wave state are
Since the propagation path can be selectively changed when the TE wave has a large electro-optical effect, it is possible to realize polarization-independent switching operation by utilizing the electro-optical effect.

Moreover, both the control optical switch 20 that constitutes the front-stage switch 62 and the rear-stage switch 64 have a small electro-optical effect.
For waves, it operates non-selectively in either the Bar state or the Cross state. Therefore, for one light X, the control light switch 20 of the latter switch 64 can provide a fixed propagation path connecting between the specific input / output ports of the latter switch 64, and for the other light Y. Is a control optical switch 20 of the front stage switch 62.
A fixed propagation path can be provided that connects between 62 specific input / output ports.

Therefore, by selectively changing the propagation path of one light X in the front stage switch 62, a propagation path connecting desired input / output ports of the optical matrix switch device 60 can be formed for one light X. Further, by selectively changing the propagation path of the other light Y in the post-stage switch 64, a propagation path connecting the desired input / output ports of the optical matrix switch device 60 can be formed for the other light Y.

Therefore, by selectively changing the propagation path of one light X in the front stage switch 62, a propagation path connecting desired input / output ports of the optical matrix switch device 60 can be formed for one light X. Further, by selectively changing the propagation path of the other light Y in the post-stage switch 64, a propagation path connecting the desired input / output ports of the optical matrix switch device 60 can be formed for the other light Y.

Further, in the above-described embodiment, since the GaAs substrate is used as the compound semiconductor crystal substrate 12, the polarized light having a large electro-optical effect is the TE wave and the polarized light having a small electro-optical effect is the TM wave, so that the control optical switch 20 is used. , Selective operation for TE wave in Cross state or Bar state, and Cross for TM wave
Although the optical switch that operates non-selectively in either the state or the bar state is created, the control optical switch 20
The operating conditions and the production conditions may be arbitrarily changed according to the substrate material.

The third embodiment can be modified similarly to the modification of the third embodiment of the first invention.

The present invention is not limited to the above-described embodiments, and the configuration of each component, forming material, placement position, numerical conditions and other design conditions can be arbitrarily changed according to the design.

For example, the substrate material may be a ferroelectric material having an optical effect, such as LiNbO ₃ or other ferroelectric crystal, or GaAs or other semiconductor material.

Further, as the structure of the front-stage and rear-stage optical matrix switches, conventionally proposed optical matrix switches of various structures may be used. Typical configurations include, for example, a duplex configuration, a crossbar type, a general tree configuration, and a simplified tree configuration.

For example, redundant configuration when the, n rows and n ² pieces of control light switch of the first group I to n are arranged in columns, the second group II the n ² control arranged in n rows and n columns Equipped with an optical switch,
N control light switches in the same row of the first group I, and the second group II
It is also possible to use an optical matrix switch having a configuration in which one control optical switch is selected from each of different columns and selected so as not to overlap with each other, and the control optical switches are connected in a one-to-one relationship. The control light switches of the first group I and the control light switches of the second group II connected in this way are all connected in a one-to-one correspondence without duplication.

Alternatively, in the case of a crossbar type configuration, for example,
n input / output waveguides in the row direction, n input / output waveguides in the column direction, and n ² control optical switches provided in the tolerance portions of the input / output waveguides in the row direction and the column direction, respectively. It may be an optical matrix switch having a configuration provided.

Further, the control optical switch may be composed of one optical switch element, or may be composed of a plurality of optical switch elements. Further, the non-selective operation of the control optical switch in either the Bar state or the Cross state with respect to the polarized light in which the electro-optical effect becomes small includes the case where it functions as a passive branch. As the optical switch element for forming the control optical switch, various configurations may be used, for example, a directional coupling type optical switching element or a total reflection type optical switching element may be used.

Further, the deviation changing means may be any suitable means that can change the deviation direction of the light.

Further, the leakage light elimination means may or may not be provided. By providing the leakage light excluding means, it is possible to make the crosstalk characteristics equal to the crosstalk characteristics of the optical matrix switch having polarization dependence.

The optical matrix switch devices of the first and second inventions are suitable for switching with a large amount of polarization (double).

(Effect of the invention) As is clear from the above description, according to the first invention of this application, a polarized light having a large electro-optical effect and a polarized light having a small electro-optical effect having polarization directions orthogonal to each other,
Input is made from the matrix switch at the front stage to the matrix switch at the rear stage via the bias changing means.

Therefore, the polarized light input to the optical matrix switch in the front stage in the state where the electro-optical effect is large propagates in the optical matrix switch in the rear stage in the state in which the electro-optical effect is small, and the electro-optical effect is small in the optical matrix switch in the front stage. The polarized light input in this state propagates through the optical matrix switch in the subsequent stage in a state where the electro-optic effect is large.

The control optical switches constituting the front and rear optical matrix switches selectively operate in the bar state or the cross state with respect to polarized light having a large electro-optical effect. When the electro-optical effect is large, the propagation path is selectively selected for the polarized light input with the large electro-optical effect and the polarized light input with the small electro-optical effect to the optical matrix switch in the previous stage. It can be changed, and switch operation can be realized at a low operating voltage.

Moreover, since the control optical switches constituting the optical matrix switches in the front stage and the rear stage both operate non-selectively in one of the bar state and the cross state for polarized light having a small electro-optical effect, The optical matrix switch of the latter stage can provide a fixed propagation path for connecting the specific input / output ports of the latter switch with respect to the polarized light inputted to the optical matrix switch of the latter in a state where the electro-optical effect is large. For polarized light input to the preceding optical matrix switch in a state where the electro-optic effect is small, the preceding optical matrix switch can provide a fixed propagation path that connects specific input / output ports of the preceding switch.

Therefore, by selectively changing the propagation path in the optical matrix switch in the preceding stage with respect to the polarized light input to the optical matrix switch in the preceding stage in a state where the electro-optic effect is large, the optical matrix switch device of the first invention is desired. It is possible to form a propagation path connecting the input and output ports of the. Furthermore, by selectively changing the propagation path in the optical matrix switch in the subsequent stage with respect to the polarized light input to the optical matrix switch in the previous stage in a state where the electro-optical effect is small, the optical matrix switch device according to the first invention is desired. It is possible to form a propagation path connecting the input and output ports of the.

Therefore, according to the first aspect of the present invention, it is possible to provide an optical matrix switch device capable of performing switching without polarization dependence at a low operating voltage when a ferroelectric crystal substrate is used.

According to the second invention of this application, polarized light having a large electro-optical effect and polarized light having a small electro-optical effect, which have polarization directions orthogonal to each other, are transmitted from the matrix switch at the front stage to the matrix switch at the rear stage through the bias changing means. Input to the switch.

Therefore, the polarized light input to the optical matrix switch in the front stage in the state where the electro-optical effect is large propagates in the optical matrix switch in the rear stage in the state in which the electro-optical effect is small, and the electro-optical effect is small in the optical matrix switch in the front stage. The polarized light input in this state propagates through the optical matrix switch in the subsequent stage in a state where the electro-optic effect is large.

The control optical switches constituting the front and rear optical matrix switches selectively operate in the bar state or the cross state with respect to polarized light having a large electro-optical effect. For polarized light input in the state where the electro-optical effect is large, the propagation path can be selectively changed by using the electro-optical effect in the state where the electro-optical effect is large in the optical matrix switch in the previous stage. For polarized light input to the optical matrix switch in the state where the electro-optical effect is small, the propagation path is selectively used by utilizing the electro-optical effect in the optical matrix switch in the subsequent stage when the electro-optical effect is large. Can be changed.

Moreover, since the control optical switches constituting the optical matrix switches in the front stage and the rear stage both operate non-selectively in one of the bar state and the cross state for polarized light having a small electro-optical effect, The optical matrix switch of the latter stage can provide a fixed propagation path for connecting the specific input / output ports of the latter switch with respect to the polarized light inputted to the optical matrix switch of the latter in a state where the electro-optical effect is large. For polarized light input to the preceding optical matrix switch in a state where the electro-optic effect is small, the preceding optical matrix switch can provide a fixed propagation path that connects specific input / output ports of the preceding switch.

Therefore, by selectively changing the propagation path in the optical matrix switch in the preceding stage with respect to the polarized light input to the optical matrix switch in the preceding stage in a state where the electro-optical effect is large, the optical matrix switch device of the second invention is desired. It is possible to form a propagation path connecting the input and output ports of the. Furthermore, by selectively changing the propagation path in the optical matrix switch in the subsequent stage with respect to the polarized light input to the optical matrix switch in the upstream stage in a state where the electro-optical effect is small, the optical matrix switch device of the second invention is desired. It is possible to form a propagation path connecting the input and output ports of the.

Therefore, according to the second aspect of the invention, it is possible to provide an optical matrix switch device capable of performing polarization-independent switching by utilizing the electro-optical effect even when a compound semiconductor crystal substrate is used. By utilizing the electro-optical effect, it is possible to provide an optical matrix switch device that operates faster and consumes less current than an optical matrix switch device that is configured using a conventional current injection type optical switch.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the first invention and a first embodiment of the second invention.
2A and 2B are explanatory diagrams of the bias changing means, FIG. 3 is a diagram for explaining the configuration of the optical switch element, and FIG. 4 is an operating condition diagram of the optical switch element. 5 (A) and 5 (B) are partially enlarged views of the operating condition diagram, and FIGS. 6 (A) and 6 (B) are explanatory diagrams of the operating example of the first embodiment, and FIG. Is a second embodiment of the first invention and a second embodiment of the second invention.
8 is an explanatory diagram of an operation example of the second embodiment, and FIG. 9 is a third embodiment of the first invention and a third embodiment of the second invention.
10 is an explanatory view of an operation example of the third embodiment, and FIG. 11 is a third embodiment of the first invention and a third embodiment of the second invention.
FIG. 8 is an explanatory diagram of a configuration of a modified example of the optical matrix switch in FIG. 10, 42, 62 (, 74) ... front optical matrix switch 20, 66, 68, 70, 76, 78 ... control optical switch 24, 44, 64 (, 74) ... rear optical matrix switch 26 ... Bias changing means 28, 40, 60 ...... Optical matrix switch device.

Claims (2)

[Claims] 1. An optical matrix switch in the preceding stage, which is composed of a ferroelectric crystal substrate, and into which polarized light having a large electro-optical effect and polarized light having a small electro-optical effect having polarization directions orthogonal to each other are input. An optical matrix switch in the latter stage, which is configured by using a dielectric crystal substrate, and into which polarized light having a large electro-optical effect and polarized light having a small electro-optical effect, which have polarization directions orthogonal to each other, are input, and the optical matrix switches in the former stage and the latter stage A switch is connected in series, and the polarization changing means for rotating the polarization direction of the polarization output from the control optical switch of the preceding optical matrix switch by 90 ° and inputting it to the control optical switch of the subsequent optical matrix switch is provided, The control optical switches of the optical matrix switches at the front stage and the rear stage are set to a bar state or a cross state for polarized light having a large electro-optical effect. And an optical switch which selectively operates in a state of light and non-selectively operates in one of a bar state and a cross state for polarized light having a small electro-optical effect. Switch device. 2. A structure using a compound semiconductor crystal substrate,
Optical matrix switch in the previous stage to which polarized light with large electro-optical effect and polarized light with small electro-optical effect are input, which have polarization directions orthogonal to each other, and compound semiconductor crystal substrate, and have polarization directions orthogonal to each other A post-stage optical matrix switch to which a polarized light having a large electro-optical effect and a polarized light having a small electro-optical effect are input, and the optical matrix switches in the preceding stage and the succeeding stage are connected in series, and a control optical switch for the preceding optical matrix switch is also provided. A polarization changing means for rotating the polarization direction of the polarized light output from the device by 90 ° and inputting it to the control optical switch of the optical matrix switch in the subsequent stage, For a large polarized light, it selectively operates in the bar state or the cross state, and the electro-optical effect Optical matrix switch device characterized by comprising as an optical switch that operates a non-selective in any one state of the bar state and the cross state to the polarization made.