JPH0575087B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light source device that emits light to a connected optical fiber.

[Conventional technology] A conventional light source device is shown in FIG.

As shown in the figure, the light source device includes a light emitting element 30,
It is generally composed of a connector 32 and a lens 33, and a fiber 34 to be connected can be connected to the connector 32.

[Problems to be solved by the invention] Generally, when the above light source is used for optical communication measurement,
There are the following problems.

When an LED is used as the light emitting element 30, the LED has the characteristic of not having polarization property and has the disadvantage of having a weak light output. Therefore, in this case, the transmission distance of the optical signal becomes shorter.

If an LD is used as the light emitting element 30, a high level of optical output can be obtained and the transmission distance can be extended, so the above
LD that eliminates the drawbacks of LED, but has polarization properties
When a single mode fiber is connected to this light source device using a , the polarization state within the fiber changes when it is affected by stress or the like from the outside. As a result, it is not possible to supply light in an accurate and stable polarization state to optical circuits that require polarization dependence, such as optical branch circuits, and it is not possible to accurately and stably measure the circuit characteristics of this optical circuit. There was a problem that made it impossible to do so.

Furthermore, when a multimode fiber is connected to a light source device using an LD, speckle noise within the multimode fiber to be measured becomes a problem.
Interference occurs between modes of light within a multimode fiber, producing speckle, which changes to produce speckle noise. For this reason, there was a problem in that it was not possible to accurately and stably measure, for example, the loss of the multimode fiber.

The present invention was made in view of the above-mentioned circumstances, and addresses the influence of the polarization state when a single mode fiber is connected as a fiber to be connected, and the influence of the polarization state when a multimode fiber is connected as a fiber to be connected. It is an object of the present invention to provide a light source device that can emit light that eliminates the effects of light noise.

Another object is to be able to change the state of polarization of the fiber to be connected and freely control it.

[Means for Solving the Problems] In order to achieve the above object, the light source device of the present invention includes a light emitting element 1 that emits light to a connected fiber 6.
an optical fiber 2 provided between the fiber 6 to be connected and the light emitting element 1; a connector 3 fixed to the optical fiber 2 and to which the fiber 6 to be connected is detachable; It is characterized by comprising an exciter 8 that mechanically pressurizes by the expansion of 10.

Further, the connected fiber 6 may be a single mode fiber 6a, and the optical fiber 2 may be a single mode fiber 2a.

Further, the connected fiber 6 may be a multimode fiber 6b, and the optical fiber 2 may be a multimode fiber 2b.

[Operation] Light from the light emitting element 1 passes through the optical fiber 2 and enters the connected fiber 6 connected to the connector 3.

At this time, the optical fiber 2 is excited by the exciter 8. The control unit 16 supplies a control signal to the exciter 8, and the piezoelectric element 10 repeatedly expands to pressurize the optical fiber 2.

Therefore, when the single mode fiber 2a is used as the optical fiber 2, the polarization state of the light is forcibly changed and the light can be emitted to the single mode fiber 6a. Therefore, by performing averaging processing in a signal processing section or the like outside the light source device, it is possible to accurately and stably measure, for example, the circuit characteristics of an optical circuit that is polarization-dependent.

Similarly, even when a multimode fiber 2b is used as the optical fiber 2 in the device and a multimode fiber 6b is connected as the connected fiber 6, the exciter 8 repeatedly pressurizes the multimode fiber 2b, and the multimode fiber The multimode fiber 6b is in a state where the light between each mode in 2b is forcibly interfered and speckles are forcibly emitted.
can be emitted to Therefore, by performing averaging processing in a signal processing section or the like outside the light source device, it is possible to accurately and stably measure, for example, the loss of a multimode fiber.

Further, the control unit 16 controls the piezoelectric element 10 of the exciter 8.
Various control signals can be outputted to the piezoelectric element 10, and the piezoelectric element 10 can change the pressurizing state of the optical fiber 2 in response to the control signals. Furthermore, since the piezoelectric element 10 mechanically presses the optical fiber 2, the stress within the optical fiber 2 becomes uniform in the X and Y directions of the cross section.

Therefore, for example, if the optical fiber is a single mode fiber 2a, if a control signal with continuous signal levels is input to the piezoelectric element 10, the polarization state of the single mode fiber 2a will be maintained at a certain constant state. be able to.

[Example] Hereinafter, an example of the light source device of the present invention will be described based on the drawings.

FIG. 1 is a schematic diagram showing a light source device.

As shown in the figure, 1 is a light emitting element such as an LD, which emits light with arbitrary polarization depending on the type or arrangement of the element. Further, this light emitting element 1 is driven by a drive circuit 1a, and can be modulated with a baseband signal as necessary. An optical fiber 2 is arranged in the emission direction of the light emitting element 1.
A connector 3 is connected to the optical fiber 2.
A fiber 6 to be connected is detachably attached to the connector 3.

A lens 4a is arranged between the light emitting element 1 and the optical fiber 2.

Further, the optical fiber 2 is provided with an exciter 8 .

FIG. 2a is a front sectional view showing this exciter 8,
FIG. 2b is a side view of FIG. 2a. As shown in the figure, the exciter 8 is constituted by components inside a hollow casing 9. A piezoelectric element 10 made of piezoelectric ceramic is erected in the hollow portion 9a of the housing 9. This piezoelectric element 10 extends in an upward direction when a voltage is applied. Further, the electrodes of the piezoelectric element 10 are connected to terminals 11a and 11b of the housing 9.

Further, on the upper part of the casing 9, a fixing member 12 for fixing the cladding of the optical fiber 2 or the UV coating on the cladding is detachably attached to the casing 9 via screws 12a and 12b. This fixing member 12
A double-nut presser screw 12c is provided in the center of the piezoelectric element 10 so as to be extendable in the direction of the piezoelectric element 10.

In addition, on the upper part of the housing 9 on both sides of the fixing member 12,
Fixing member 1 for fixing the nylon coating of the optical fiber 2
3 is removably attached to the housing 9 with a screw 13a.

The cladding or UV coating of the optical fiber 2 is sandwiched between the fixing member 12 and the piezoelectric element 10.
is a presser plate 14, 1 made of baking or glass, etc.
4 and a presser plate 15, 1 made of stainless steel or the like.
The piezoelectric element 10 is sandwiched between the fixing member 12 and the piezoelectric element 10 via the fixing member 12 and the piezoelectric element 10.

The terminals 11a and 11b are connected to the control unit 1.
6. The control unit 16 controls the piezoelectric element 1
It generates a DC or AC applied voltage with respect to 0 and controls the pressing force on the optical fiber 2. Furthermore, this control section 16 can supply a control signal whose voltage changes periodically to the piezoelectric element 10. As the control signal, for example, a 50 Hz SIN wave from a commercial power source can be used, and the waveform and frequency can be set arbitrarily.

Next, the operation of the above configuration will be explained.

The light from the light emitting element 1 passes through the lens 4a and the optical fiber 2, and enters the connected fiber 6 connected to the connector 3. At this time, since the light emitting element 1 is an LD, the light is polarized in a predetermined direction.

However, at this time, the optical fiber 2 is repeatedly mechanically excited by the exciter 8. The control unit 16 supplies a control signal to the exciter 8, and the piezoelectric element 1
0 repeats stretching and pressurizes the optical fiber 2.

Therefore, when the single mode fiber 2a is used as the optical fiber, the polarization state of the light is forcibly changed within the single mode fiber 2a, and the light can be emitted. Then, the connected fiber 6
A single mode fiber 6a is connected as a single mode fiber 6a, and the light from the output end of the single mode fiber 6a can also be emitted with its polarization state forcibly changed. Therefore, by performing averaging processing in a signal processing section or the like outside the light source device, it is possible to accurately and stably measure, for example, the circuit characteristics of an optical circuit that is polarization-dependent.

Next, a light source device for multimode fiber will be explained.
This can be applied by simply using the multimode fiber 2b, and the drawing is omitted.

In this case, the exciter 8 excites the multimode fiber 2b. At this time, the light between the respective modes in the multimode fiber 2b is forcibly interfered and can be emitted with speckles forcibly produced. A multimode fiber 6b is connected as the fiber 6 to be connected, and the light from the output end of the multimode fiber 6b can also be emitted with forced speckles. Therefore, by performing averaging processing in a signal processing section or the like outside the light source device, it is possible to accurately and stably measure, for example, the loss of a multimode fiber.

In the above-described embodiment, the exciter 8 is configured to repeatedly pressurize the optical fiber 2, but it may also be configured to shake the optical fiber 2.

[Effects of the Invention] As explained above, according to the light source device of the present invention, the polarization of light can be forcibly changed to a single mode fiber as a connected fiber without being affected by an external force on the single mode fiber. It can be emitted by changing to Furthermore, by controlling the control signal to the exciter and pressurizing the single mode fiber with a constant force, light with a constant polarization state can be emitted.

Furthermore, light with speckle noise can be forcibly emitted from a multimode fiber as a fiber to be connected without being affected by an external force applied to the multimode fiber. In addition, regardless of whether a single mode fiber or multimode fiber is used as the fiber to be connected, if a signal processing unit is installed outside the light source device to perform averaging processing, the effect of polarization when using a single mode fiber can be improved. When using a multimode fiber, the influence of speckle fluctuations can be eliminated, and accurate and stable measurements can be performed in either case.

In addition, since the exciter is configured to include a piezoelectric element and mechanically pressurize the optical fiber, the state of pressurization of the optical fiber can be arbitrarily changed in accordance with a control signal from the control section.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a light source device of the present invention, FIGS. 2a and 2b are front sectional views and side views showing an exciter used in the light source device, and FIG. FIG. 2 is a diagram showing a light source device of FIG. 1... Light emitting element, 1a... Light emitting element drive circuit,
2...Optical fiber, 2a...Single mode fiber, 2b...Multimode fiber, 3...Connector, 4a...Lens, 6...Connected fiber, 6a...Single mode fiber, 6b...
Multimode fiber, 8... Exciter, 16...
control section.

Claims (1)

[Claims] 1. Light emitting element 1 that emits light to connected fiber 6
an optical fiber 2 provided between the fiber 6 to be connected and the light emitting element 1; a connector 3 fixed to the optical fiber 2 and to which the fiber 6 to be connected is detachable; 1. A light source device comprising: an exciter 8 that mechanically pressurizes by stretching 10; 2. The light source device according to claim 1, wherein the connected fiber 6 is a single mode fiber 6a, and the optical fiber 2 is a single mode fiber 2a. 3. The light source device according to claim 1, wherein the connected fiber 6 is a multimode fiber 6b, and the optical fiber 2 is a multimode fiber 2b.