JP5236582B2 - Optical output device - Google Patents

Description

  The present invention relates to an optical output device.

  Increasing communication capacity is widely performed using a wavelength division multiplexing system (hereinafter, WDM system).

  Generally, in order to increase the communication capacity, it is necessary to increase the number of channels. However, as the number of channels increases, the spacing between channels decreases. Therefore, it is required to tune and lock the wavelength of the laser beam to the channel wavelength with high accuracy.

  FIG. 7 is a diagram illustrating an example of an optical output device 1 that outputs laser light of a channel CHx selected from a plurality of channels CHa to CHn.

  Hereinafter, each part of the light output device 1 will be described.

  The storage unit 30 stores a reference driving condition corresponding to each channel in association with each channel. Here, a case where the reference temperature is stored in the storage unit 30 as a reference drive condition is taken as an example. The significance of the reference temperature will be described later.

  The laser array 3 includes a plurality of laser elements 3a to 3n in which the wavelength of the laser light changes according to the driving conditions. Each laser element is arranged on a common base, and at least one of a plurality of channels CHa to CHn corresponding to different wavelength ranges is assigned thereto. For example, the channel CHa is assigned to the laser element 3a, and the channel CHb is assigned to the laser element 3b. Here, the case where each laser element is a laser element in which the wavelength of laser light changes according to temperature is taken as an example.

  When any one of these laser elements is selected by the switch 17, a drive current is applied to the selected laser element 3x by the current source 20. The current control unit 25 controls the drive current applied to the laser element 3x. As a result of the drive current being applied to the laser element 3x, the laser element 3x starts driving, and laser light is output from the laser element 3x. The dotted line shown in FIG. 7 indicates the laser beam output from the laser element 3x.

  In the light output device 1, the temperature of the laser array 3 can be adjusted. That is, the first temperature control unit 26 adjusts the temperature of the laser element 3 x while monitoring the temperature detected by the temperature sensor 7 disposed in the vicinity of the laser array 3. The thermoelectric element 15 (for example, a Peltier element) and the controller 18 are used for temperature adjustment by the first temperature control unit 26.

  After passing through the coupler 4, the laser light is amplified by an optical amplifier 5 that is driven according to a drive current based on a current source 21. Thereafter, the laser light is output to the optical fiber 13 through the beam splitters 6a and 6b and the condenser lens 12 in this order.

  The laser beam is also output to the light receiving element 8 that detects the light power. The detection result of the light receiving element 8 is provided to the power control unit 27. Further, the laser light passes through the optical filter 10 and is also output to the light receiving element 9 that detects the light power. The detection result of the light receiving element 9 is provided to the wavelength control unit 28 for wavelength locking.

  The optical filter 10 is used for wavelength locking. As the optical filter 10, an etalon filter whose light transmittance periodically changes at each wavelength interval between channels is used.

  In the optical output device 1, the temperature of the optical filter 10 can also be adjusted. That is, the second temperature control unit 29 adjusts the temperature of the optical filter 10 while monitoring the temperature detected by the temperature sensor 11 disposed in the vicinity of the optical filter 10. The thermoelectric element 16 and the controller 19 are used for temperature adjustment by the second temperature control unit 29.

  Hereinafter, a flow of processing performed when the channel CHx is selected (that is, when the laser element 3x to which the channel CHx is assigned is selected by the switch 17) will be described.

  In this case, the second temperature control unit 29 performs so-called ATC (Auto Temperature Control) control and adjusts the temperature of the optical filter 10 to be a predetermined temperature.

  And the 1st temperature control part 26 performs ATC control, and adjusts the wavelength of a laser beam so that it may become a wavelength within the wavelength range corresponding to channel CHx. That is, the first temperature control unit 26 adjusts the temperature of the laser element 3x so as to be the reference temperature Tx associated with the channel CHx so that the wavelength of the laser light falls within the wavelength range corresponding to the channel CHx.

  In addition, the current control unit 25 performs so-called ACC (Auto Current Control) control, and adjusts the drive current applied to the laser element 3x so as to be a predetermined current.

  Further, the power control unit 27 performs so-called APC (Auto Power Control) control to adjust the power of the laser beam to a predetermined power.

  As a result of the ATC control by the first temperature control unit 26, it is estimated that the wavelength of the laser light has become a wavelength within the wavelength range corresponding to the channel CHx.

  Therefore, the wavelength control unit 28 performs so-called AFC (Auto Frequency Control) control to tune and lock the wavelength of the laser beam to the channel wavelength λx of the channel CHx, and the power of the light detected by the light receiving element 8. The temperature of the laser element 3x is continuously adjusted based on the comparison result with the light power detected by the light receiving element 9 (for example, the transmittance when the laser light is transmitted through the optical filter 10). As a result, the wavelength of the laser light is tuned to the channel wavelength λx. Even if a wavelength drift occurs due to deterioration of the laser element 3x, the wavelength of the laser beam is maintained in the channel λx.

  As described above, in the optical output device 1, when the wavelength of the laser beam is locked to the channel wavelength λx of the channel CHx, the temperature of the laser element 3x is set in order to keep the wavelength of the laser beam within the wavelength range corresponding to the channel CHx. Is adjusted to the reference temperature Tx corresponding to the channel CHx. Thereafter, the wavelength of the laser light is tuned to the channel wavelength λx and locked by AFC control. This is the same when other laser elements are selected.

  Patent Document 1 below discloses a technique for locking the wavelength of a laser beam to a channel wavelength even when the characteristics of the optical filter 10 change with temperature.

JP 2003-188468 A

  For example, when a certain laser element (here, referred to as laser element 3a) is driven in the optical output device 1, not only the laser element 3a itself but also another laser element (here, laser element 3b and Deterioration) occurs. Therefore, wavelength drift due to deterioration also occurs in the laser element 3b.

  Therefore, when the laser element 3b is selected, even if the temperature of the laser element 3b is adjusted to the reference temperature Tb associated with the channel CHb, the wavelength of the laser light may not be within the wavelength range corresponding to the channel CHb. There is sex. As a result, there is a possibility that the wavelength of the laser beam cannot be reliably tuned to the channel wavelength of the channel CHb. For example, the wavelength of the laser beam may not be tuned to the channel wavelength in a short time.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to achieve certainty when tuning the wavelength of laser light to a target wavelength in an optical output device capable of changing the wavelength of laser light. .

  In order to solve the above-described problems, an optical output device according to the present invention includes a plurality of laser elements that are arranged on a common base and the wavelength of laser light changes according to driving conditions, and any one of the plurality of laser elements. Is selected as a selected laser element, a current source for applying a current to the selected laser element and a driving condition of the selected laser element are set to a reference condition related to each of the plurality of laser elements. Of these, a first adjustment unit that adjusts so as to satisfy a reference condition related to the selected laser element, an optical amplification unit that amplifies the power of the laser beam output from the selected laser element to a predetermined amount, and a transmission characteristic of the laser An optical filter that periodically changes according to the wavelength of light, the power of the laser light amplified by the optical amplification unit, and the laser light amplified by the optical amplification unit after passing through the optical filter A power comparison unit that compares the selected laser element and the power comparison unit when the drive condition of the selected laser element becomes a reference condition related to the selected laser element as a result of adjustment by the first adjustment unit. A second adjusting unit that adjusts the drive condition of the selected laser element so that the wavelength of the laser beam output from the selected laser element becomes a target wavelength corresponding to the selected laser element based on the comparison result of The first adjusting unit, when another laser element is selected as a new selected laser element, sets a driving condition of the new selected laser element as the first selected laser element. 2 related to the new selected laser element corrected based on the drive condition of the selected laser element when the adjustment by the adjustment unit was performed and the reference condition related to the selected laser So that the semi-condition, adjusting, characterized by.

  In one embodiment of the present invention, the selected laser element is based on the drive condition of the selected laser element adjusted by the second adjustment unit and the reference condition related to the selected laser element. And a correction unit that corrects reference conditions related to other laser elements.

  In the aspect of the invention, the correction unit may be associated with the laser element such that a correction amount changes according to a distance between the laser element other than the selected laser element and the selected laser element. The reference condition is corrected.

  In one aspect of the present invention, the drive condition of the selected laser element is a temperature of the selected laser element, and the reference condition related to the laser element is a reference temperature related to the laser element, The first adjustment unit adjusts the temperature of the selected laser element to be a reference temperature related to the selected laser element, and the second adjustment unit is a result of control by the first adjustment unit, When the temperature of the selected laser element becomes the reference temperature related to the selected laser element, the wavelength of the laser beam output from the selected laser element is based on the comparison result by the power comparison unit. The temperature of the selected laser element is adjusted so as to obtain a target wavelength corresponding to the selected laser element.

  In one embodiment of the present invention, the driving condition of the selected laser element is a current applied to the selected laser element, and the reference condition related to the laser element is a reference related to the laser element. The first adjustment unit adjusts the current applied to the selected laser element so as to become a reference current related to the selected laser element, and the second adjustment unit includes the first adjustment unit. When the current applied to the selected laser element becomes the reference current related to the selected laser element as a result of control by the adjustment unit, the selected target is selected based on the comparison result by the power comparison unit. The current applied to the selected laser element is adjusted so that the wavelength of the laser beam output from the laser element becomes a target wavelength corresponding to the selected laser element.

It is a block diagram of the optical output device which concerns on embodiment of this invention. It is a figure which shows an example of the table memorize | stored in a memory | storage part. It is a figure which shows the relationship between the transmittance | permeability of a laser beam, and the wavelength of a laser beam. It is a flowchart of the process performed in an optical output device. It is a flowchart of the process performed in an optical output device. It is a figure which shows an example of correction amount control information. It is a figure which shows an example of the conventional light output device.

  Hereinafter, examples of embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a light output device 31 according to an embodiment of the present invention. The light output device 31 outputs laser light of a channel selected from the plurality of channels CHa to CHn.

[1. Constitution]
Hereinafter, the configuration of the light output device 31 will be described.

  The current control unit 55, the first temperature control unit 56, the power control unit 57, the wavelength control unit 58, the second temperature control unit 59, and the correction unit 61 are, for example, a microcomputer that operates according to a predetermined program.

  The storage unit 60 is a known storage unit (for example, ROM or RAM). The storage unit 60 stores reference drive conditions in association with each channel. FIG. 2 shows an example of a table stored in the storage unit 60. As shown in the figure, in this table, a reference temperature is stored as a reference drive condition in association with each channel. As will be described later, each channel is assigned to any one of the laser elements 33a to 33n. Each channel corresponds to a different wavelength range (capture range described later). The contents of this table are updated by the correction unit 61.

  The laser array 33 includes a plurality of laser elements 33a to 33n in which the wavelength of the laser light changes according to the driving conditions. Here, it is assumed that each laser element is a DFB (Distributed Feedback) laser element in which the wavelength of the laser light changes according to the temperature. Each laser element is arranged on a common base, and any one of the channels CHa to CHn is assigned to each laser element. For example, the channel CHa is assigned to the laser element 33a, and the channel CHb is assigned to the laser element 33b.

  Any one of these laser elements is selected by the switch 47. For example, when a certain channel CHx is selected, the laser element 33x to which the channel CHx is assigned is selected by the switch 47. When the laser element 33x (selected laser element) is selected, a drive current is applied from the current source 50 to the laser element 33x. When the current control unit 55 controls the current source 50, the drive current applied to the laser element 33x is adjusted.

  As a result of the drive current being applied to the laser element 33x, the laser element 33x starts driving, and laser light is output from the laser element 33x. The dotted line shown in FIG. 1 indicates the laser beam output from the laser element 33x.

  In this light output device 31, the temperature of the laser array 33 can be adjusted. That is, a thermoelectric element 45 (for example, a Peltier element) is disposed in the vicinity of the laser array 33, and the thermoelectric element 45 heats or cools the laser array 33. The thermoelectric element 45 is controlled by a controller 48. The controller 48 controls the thermoelectric element 45 based on instructions from the first temperature control unit 56 and the wavelength control unit 58. The detected temperature of the temperature sensor 37 disposed in the vicinity of the laser array 33 is provided to the first temperature control unit 56.

  The laser light passes through the coupler 34 and is then amplified by the optical amplifier 35. The optical amplifier 35 is driven according to the drive current applied by the current source 51. The power control unit 57 controls the current source 51.

  The laser light amplified in the optical amplifier 35 is divided into transmitted light and reflected light by the beam splitter 36a. The reflected light of the beam splitter 36a is output to a light receiving element 38 that detects the power of the light. The detection result of the light receiving element 38 is provided to the power control unit 57.

  The transmitted light of the beam splitter 36a is further divided into transmitted light and reflected light by the beam splitter 36b. The reflected light of the beam splitter 36b passes through the optical filter 40 and is output to the light receiving element 39 that detects the power of the light. The detection result of the light receiving element 39 is provided to the wavelength controller 58.

  The light transmitted through the beam splitter 36 b passes through the condenser lens 42 that collects the light and is output to the optical fiber 43.

  Here, the optical filter 40 will be described. The optical filter 40 is a filter whose light transmittance periodically changes at each wavelength interval Δλ between the channels, and is an etalon filter, for example. The optical filter 40 is used for wavelength locking.

  FIG. 3 is a diagram showing the relationship between the transmittance of laser light and the wavelength of laser light. The horizontal axis indicates the wavelength λ of the laser beam, and the vertical axis indicates the transmittance P of the laser beam. As shown in the figure, the transmittance P changes periodically every Δλ. Since the wavelength interval between the channels and the period of change of the transmittance P are the same (that is, Δλ), the transmittance is P0 (hereinafter referred to as the reference transmittance) regardless of the channel wavelength of the laser light. . For example, as shown in FIG. 3, the transmittance of both the laser beam having the channel wavelength λa of the channel CHa and the laser beam having the channel wavelength λb of the channel CHb is P0. The wavelength range of the width Δλ from the wavelength λ1 to the wavelength λ2 indicates the wavelength range corresponding to the channel CHa (hereinafter referred to as the capture range), and the wavelength range of the width Δλ from the wavelength λ2 to the wavelength λ3 is the channel range. The capture range corresponding to CHb is shown.

  A thermoelectric element 46 (for example, a Peltier element) is disposed in the vicinity of the optical filter 40, and the thermoelectric element 46 heats or cools the optical filter 40. The thermoelectric element 46 is controlled by a controller 49. The controller 49 controls the thermoelectric element 46 based on an instruction from the second temperature control unit 59. The temperature detected by the temperature sensor 41 disposed in the vicinity of the optical filter 40 is provided to the second temperature control unit 59.

[2. processing]
FIG. 4 is a diagram showing a flow of processing performed when any one of the channels CHa to CHn is selected (that is, when the laser element 33x is selected).

  As shown in the figure, first, the second temperature control unit 59 performs ATC control and adjusts the temperature of the optical filter 40 so that the reference filter temperature is stored in advance in the storage unit 60 (S101). For example, the second temperature control unit 59 issues an instruction to the controller 49 while monitoring the detected temperature detected by the temperature sensor 41, and adjusts the detected temperature so that the difference from the reference filter temperature is a predetermined value or less.

  Then, the first temperature control unit 56 (first adjustment unit) performs ATC control, and the temperature of the laser element 33x (the reference temperature related to the laser element 33x among the reference temperatures stored in the storage unit 60 ( (Driving condition) is adjusted (S102). That is, the first temperature control unit 56 adjusts the temperature of the laser element 33x so that the reference temperature Tx associated with the channel CHx is reached. For example, the first temperature control unit 56 instructs the controller 48 while monitoring the detected temperature T detected by the temperature sensor 37, and adjusts the detected temperature T so that the difference from the reference temperature Tx is equal to or less than a predetermined value. . By the step of S102, the wavelength of the laser beam is set to a wavelength within the capture range corresponding to the channel CHx.

  Then, the current control unit 55 performs ACC control and adjusts the drive current applied to the laser element 33x so that the reference current is stored in advance in the storage unit 60 (S103). Specifically, the current control unit 55 controls the current source 51 so that the drive current applied to the laser element 33x becomes the reference current.

  Then, the power control unit 57 (light amplification unit) performs APC control, and amplifies the power of the laser light to a predetermined power (S104). Specifically, the power control unit 57 controls the current source 51 so that the difference between the detection result and the predetermined power becomes a predetermined value or less while monitoring the detection result (power) of the light receiving element 38.

  As a result of the temperature adjustment (S102) by the first temperature control unit 56, when the temperature of the laser element 33x becomes the reference temperature Tx (for example, the difference between the detected temperature T and the reference temperature Tx is equal to or less than a predetermined value). ), Step S105 is performed.

  That is, the wavelength control unit 58 (power comparison unit, second adjustment unit) performs AFC control. Specifically, the wavelength control unit 58 compares the power detected by the light receiving element 38 with the power detected by the light receiving element 39 (S201 described below: FIG. 5), and based on the comparison result, The temperature of the laser element 33x is adjusted so that the wavelength of the laser beam becomes the channel wavelength λx (S202 and S203 described later: FIG. 5).

  Further, the correction unit 61 corrects the reference temperature related to the laser elements other than the laser element 33 x based on the temperature of the laser element 33 x when the temperature control is performed by the wavelength control unit 58 and the reference temperature Tx. (S204 and S205 described later: FIG. 5).

  FIG. 5 is a diagram for specifically explaining the step of S105. The steps shown in the figure are performed periodically, for example.

  First, the wavelength controller 58 calculates the transmittance P (comparison result) by calculating the ratio between the power detected by the light receiving element 38 and the power detected by the light receiving element 39 (S201).

  Then, the wavelength controller 58 determines whether or not the wavelength of the laser light is close to the channel wavelength λx. More specifically, the wavelength controller 58 determines whether or not the absolute value ΔP of the difference between the transmittance P and the reference transmittance P0 is equal to or less than a predetermined value Pth (S202).

  When the wavelength of the laser light is not close to the channel wavelength λx, that is, when ΔP is larger than Pth (N in S202), the wavelength control unit 58 uses the laser element 33x so that the wavelength of the laser light becomes the channel wavelength λx. Is adjusted (S203). In other words, the wavelength control unit 58 adjusts the temperature of the laser element 33x so that ΔP becomes Pth or less. Specifically, the wavelength control unit 58 instructs the controller 48 so that the wavelength of the laser light becomes the channel wavelength λx while monitoring the detected temperature T.

  By the AFC control (S201 to S203), the wavelength of the laser light is adjusted to approximately the channel wavelength λx. Further, after the wavelength of the laser light is adjusted to the channel wavelength λx, even if the laser element 33x is deteriorated, the wavelength of the laser light is substantially locked to the channel wavelength λx.

  When the wavelength of the laser beam is locked to the channel wavelength λx, the correction unit 61 performs steps S204 and S205.

  That is, when ΔP is equal to or less than Pth (Y in S202), the correction unit 61 generates a correction parameter ΔTp based on the comparison between the temperature of the laser element 33x and the reference temperature Tx (S204). Specifically, the correction unit 61 calculates a difference obtained by subtracting the reference temperature Tx from the detected temperature T of the temperature sensor 37 as ΔTp. Here, ΔTp is a value that reflects the influence of the deterioration of the laser element 33x on the laser element 33x itself.

  Laser elements other than the laser element 33x are also considered to deteriorate due to the influence of the laser element 33x. Therefore, the correction unit 61 corrects the reference temperature related to the laser elements other than the laser element 33x based on the correction parameter ΔTp (S205). For example, when correcting the reference temperature related to the laser element 33y, the reference temperature Ty corresponding to the channel CHy is corrected. Specifically, the correction unit 61 adds the correction parameter ΔTp to the reference temperature Ty. Thereafter, the correction unit 61 corrects the reference temperature Tx in the same manner as in step S205 (S206).

  For example, assume that channel CHy is selected after channel CHx. That is, it is assumed that the laser element 33y is selected next to the laser element 33x. In this case, the first temperature control unit 56 performs the step of S205 based on the temperature of the laser element 33x and the reference temperature Tx when the temperature control (S202 to S203) is performed by the wavelength control unit 58 in the step of S102. Thus, the temperature of the laser element 33y is adjusted so that the reference temperature Ty corrected in step S1 is reached.

[3. Summary]
As described above, in the light output device 31, the correction parameter ΔTp reflecting the influence of the deterioration of the laser element 33x on the laser element 33x itself is acquired. Based on this ΔTp, the reference temperature Ty related to the laser elements (described as laser element 33y) other than the laser element 33x is updated. Therefore, when the laser element 33y is selected, even if the laser element 33y is deteriorated, when the temperature adjustment (S102) is performed by the first temperature control unit 56, the wavelength of the laser beam is captured corresponding to the channel CHy. Easier to fit within range. As a result, the wavelength of the laser beam is surely tuned to the channel wavelength λy and locked.

  Note that the present invention is not limited to the embodiment described above.

[4. Modification 1]
For example, one of the causes that other laser elements deteriorate due to the driving of the laser element 33x is the heat generation of the laser element 33x. In this case, the influence of the heat generated by the laser element 33x is considered to be smaller as the distance from the laser element 33x increases. Therefore, when the correction unit 61 corrects the reference temperature Ty related to a laser element other than the laser element 33x (for example, the laser element 33y), the correction amount changes according to the distance between the laser element 33x and the laser element 33y. In this way, the reference temperature Ty may be corrected. Hereinafter, this aspect (hereinafter referred to as Modification 1) will be described.

  In the first modification, correction amount control information is also stored in the storage unit 60. FIG. 6 is a diagram illustrating an example of the correction amount control information. As shown in the figure, the correction amount control information is data in which a combination of channels and a correction amount control parameter α are associated with each other. Here, the correction control information is set so that the correction amount control parameter α is smaller as the distance between the two laser elements to which each of the two channels related to the combination is assigned is larger.

  On this basis, when the correction unit 61 corrects the reference temperature Ty related to the laser element 33y other than the laser element 33x in step S205, the correction amount control parameter α associated with the combination of the channel CHx and the channel CHy. And the correction parameter ΔTp calculated in step S204 is added to the reference temperature Ty. In this way, the correction amount of the reference temperature Ty decreases as the distance between the laser element 33y and the laser element 33x increases, so that the correction amount does not become too large or too small for the deterioration of the laser element 33y. Also from this point, when the laser element 33y is selected, the wavelength of the laser light is surely tuned and locked by the channel wavelength λy.

[5. Modification 2]
Each laser element may be a DBR (Distributed Bragg Reflector) laser element in which the wavelength of the laser light changes according to the applied drive current. That is, the drive condition may be a drive current instead of a temperature.

  In this case, the reference current is stored in the table shown in FIG. 3 as the reference drive condition corresponding to each channel. Then, the current control unit (first adjustment unit) 55 is applied to the laser element 33x so as to become a reference current related to the laser element 33x (that is, a reference current related to the channel CHx) in step S103. Adjust the drive current. Further, the wavelength control unit 58 (power comparison unit, second adjustment unit) is based on the comparison result between the power detected by the light receiving element 38 and the power detected by the light receiving element 39 in steps S202 and S203. The drive current applied to the laser element 33x is adjusted so that the wavelength of the laser light becomes the channel wavelength λx. Further, the correction unit 61 performs laser elements other than the laser element 33x based on the drive current of the laser element 33x and the reference current when the current adjustment is performed by the wavelength control unit 58 in steps S204 and S205. The reference current related to is corrected.

[6. Others]
For example, the temperature sensor 37 may be installed in each laser element. In this case, the detection temperature T of the temperature sensor 37 installed in the laser element 33x corresponds to the “temperature of the laser element 33x”.

  Further, for example, the correction unit 61 may execute step S205 only when the absolute value of the correction parameter ΔTp is larger than a predetermined value. In this way, the processing load related to the correction of the reference temperature is reduced.

  Further, for example, the correction unit 61 may store the correction parameter ΔTp calculated in the step of S204 in the storage unit 60 instead of correcting the reference temperature in the step of S205. In such a case, when the laser element (for example, the laser element 33y) other than the laser element 33x is selected, the correction unit 61 performs the reference temperature Ty before the first temperature control unit 56 performs the ATC control (S102). May be corrected based on the correction parameter ΔTp stored in the storage unit 60. For example, the correction unit 61 may calculate the average of the sums (ΣΔTp) of the correction parameters ΔTp accumulated in the storage unit 60 and add this to the reference temperature Ty.

  The present invention is applicable not only when one channel is assigned to each laser element but also when a plurality of channels are assigned to each laser element.

  31 Optical output device, 33 Laser array, 34 Coupler, 35 Optical amplifier, 36 Beam splitter, 37, 41 Temperature sensor, 38, 39 Light receiving element, 40 Optical filter, 42 Condensing lens, 43 Optical fiber, 45, 46 Thermoelectric element , 47 switch, 48, 49 controller, 50, 51 current source, 55 current control unit, 56 first temperature control unit, 57 power control unit, 58 wavelength control unit, 59 second temperature control unit, 60 storage unit, 61 correction Department.

Claims (3)

A plurality of laser elements arranged on a common base, the wavelength of the laser light changing according to driving conditions;
A current source for applying a drive current to the selected laser element when any of the plurality of laser elements is selected as the selected laser element;
A first adjusting unit that adjusts the drive condition of the selected laser element to be a reference condition related to the selected laser element among reference conditions related to each of the plurality of laser elements;
An optical amplifying unit for amplifying the power of the laser light output from the selected laser element to a predetermined amount;
An optical filter whose transmission characteristics periodically change according to the wavelength of the laser beam;
A power comparison unit that compares the power of the laser light amplified by the optical amplification unit and the power after the laser light amplified by the optical amplification unit has passed through the optical filter;
As a result of adjustment by the first adjustment unit, when the driving condition of the selected laser element becomes a reference condition related to the selected laser element, the selected laser is based on the comparison result by the power comparison unit. A second adjustment unit that adjusts the drive condition of the selected laser element so that the wavelength of the laser beam output from the element becomes a target wavelength corresponding to the selected laser element;
A reference condition related to a laser element other than the selected laser element based on the drive condition of the selected laser element adjusted by the second adjustment unit and the reference condition related to the selected laser element A correction unit for correcting
Only including,
The first adjustment unit includes:
When a laser element other than the selected laser element is selected as a new selected laser element, the new selected laser element in which the driving condition of the new selected laser element is corrected by the correction unit Adjusted to be the reference condition related to
The driving condition is temperature,
The reference condition is a reference temperature,
The correction unit is
Correcting a reference condition related to the laser element such that the correction amount changes according to the distance between the laser element other than the selected laser element and the selected laser element;
An optical output device characterized by the above. The light output device according to claim 1,
The correction amount is smaller as the distance between the selected laser element and a laser element other than the selected laser element is larger.
Light output device you characterized. The light output device according to claim 1 or 2,
The driving condition is not a temperature but a driving current,
The reference condition is not a reference temperature but a reference current,
Light output device you characterized.

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