JP2000022258A - Wavelength stabilizer for array laser light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength stabilizer which controls the wavelength of an array laser light source highly accurately. SOLUTION: A wavelength-multiplexed light generating circuit 101 generates a wavelength-multiplexed light comprising a plurality of multiplexed light previously stabilized highly accurately. Then, wavelength of an array laser light source 103 is synchronized with the wavelength of the wavelength-multiplexed light by injecting the wavelength-multiplexed light into the array laser light source 103 via light input/output means 102. The wavelength-multiplexed light or a plurality of single wavelength light is extracted from the array laser source via the light input/output means 102. A wavelength selecting element for selecting/outputting a plurality of or one wavelength light for the array laser light source may be provided. The wavelength-multiplexed light generating circuit may be composed of an optical comb frequency generator or a combination of a plurality of semiconductor lasers, a wavelength monitoring circuit and multiplexer means. The light input/output means may be composed of an optical circulator and an optical branch circuit or an optical multiplexer circuit. The array laser source may be composed of a integrated device of a plurality of the array semiconductor laser and the optical multiplexer circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for switching a wavelength division type communication path (wavelength multiplex communication switch, repeater, etc.).
The present invention relates to a wavelength stabilizing device of an array laser light source applied to, for example,

[0002]

2. Description of the Related Art A light source used in wavelength division multiplexing communication is mainly a semiconductor laser, and its oscillation wavelength fluctuates due to aging and temperature change. Therefore, an apparatus for simultaneously and accurately measuring the wavelengths of a plurality of semiconductor lasers is required.

A conventional wavelength monitoring apparatus for monitoring each wavelength of wavelength-division multiplexed light generally sweeps the transmission center wavelength of a sweep type optical filter (for example, a sweep type Fabry-Perot interferometer) with time, and converts a wavelength error signal into a time domain. To perform wavelength discrimination. Further, wavelength discrimination is performed by wavelength multiplexing the output light of the semiconductor laser oscillating at a plurality of different wavelengths.

FIG. 16 shows an example of the configuration of a conventional wavelength monitoring device (Ref. 1: Suzuki et al., “Two Electrode MQWDFB-
622Mbit / s-16ch FDM Coherent Optical Transmission System Using LD ", IEICE (BI), Vo
1. , J77-BI, No. 5, pp. 294-30
3, 1994).

In FIG. 16, a reference wavelength light R and a wavelength multiplexed light M are multiplexed by an optical coupler 671 and input to a sweep type Fabry-Perot interferometer 672. The swept Fabry-Perot interferometer 672 includes a sawtooth generator 7 synchronized with an oscillator 675.
The light is swept by the sawtooth wave sa generated in FIG. 6 (FIG. 17A), and the light having the wavelength corresponding to the transmission center wavelength is received by the photodetector 673. The output pulse sb of the photodetector 673 (FIG. 17)
17B, the peak position is differentiated and detected by the differentiator 678 (FIG. 17C), and the sampling pulse sd corresponding to the peak position is obtained by the sampling circuit 679 (FIG. 17).
(D)). This sampling pulse and the output signal se (FIG. 17 (e)) of the oscillator 675 are input to the synchronous detector 680, and the output thereof is supplied to the sample-and-hold circuit 6.
81 is input. Since the saw-tooth wave sa and the output signal se of the oscillator 675 are synchronized, the phase of the output signal se of the oscillator 675 is detected by the sampling pulse sd, and the sample-and-hold circuit 681 holds the detection output, thereby obtaining an error signal. sf (FIG. 17F) can be obtained. The selector 674 sequentially switches and outputs a relative wavelength error signal between each wavelength of the reference wavelength light R and the wavelength multiplexed light M and the transmission center wavelength of the swept Fabry-Perot interferometer 672.

The error signal corresponding to the reference wavelength light R is added to a sawtooth wave output from the sawtooth wave generator 676 by an adder 677 and applied to a sweep type Fabry-Perot interferometer 672, which corresponds to the reference wavelength light R. The position of the output pulse from the photodetector 673 is controlled so as to be at the bias point of the sawtooth wave. Thus, the transmission center wavelength of the sweep type Fabry-Perot interferometer 672 can be stabilized at the wavelength of the reference wavelength light R, and a temperature compensation function for fluctuations in the ambient temperature can be provided.

An error signal corresponding to each wavelength of the wavelength multiplexed light M is negatively fed back to each light source of the wavelength multiplexed light M, and the injection current or temperature thereof is controlled to stabilize the wavelength of the wavelength multiplexed light M. Can be achieved.

The sweep type Fabry-Perot interferometer used in the conventional configuration described above requires a mechanism for sweeping the resonator length by a piezoelectric element, but can be realized by a relatively simple optical circuit. Further, by appropriately selecting the transmission center wavelength and the pass band width of the swept Fabry-Perot interferometer, there is an advantage that a wide-range wavelength change can be monitored with a desired resolution.

[0009]

By the way, in the conventional structure as described above, the sweep type Fabry-Perot interferometer sweeps the resonator length by the piezoelectric element, and therefore, as shown in FIG. Hysteresis in the amount of displacement limits measurement accuracy. In other words, the swept Fabry-Perot interferometer is for measuring the relative wavelength difference, and the accuracy with respect to the absolute wavelength is not guaranteed.

The present invention has been made in view of the above points, and has as its object to provide a wavelength stabilizing device for an array laser light source that controls the wavelength of the array laser light source with high accuracy.

[0011]

In order to achieve the above object, a first aspect of the present invention is a wavelength multiplexing light generating means for generating a wavelength multiplexing light obtained by multiplexing a plurality of wavelength lights stabilized in advance with high accuracy. Light input means for synchronizing the wavelength of the array laser light source with the wavelength of the wavelength multiplexed light by injecting the wavelength multiplexed light generated from the wavelength multiplexed light generation circuit into the array laser light source, and wavelength stabilized. Light output means for extracting wavelength multiplexed light or a plurality of single wavelength lights from the array laser light source.

Preferably, the optical input means and the optical output means include an optical circulator and an optical branching circuit or an optical demultiplexing circuit, and the optical circulator and the optical branching circuit or the optical demultiplexing circuit are used for the optical circulator. By injecting the wavelength multiplexed light generated from the wavelength multiplexed light generating means into the array laser light source, the wavelength of the array laser light source is synchronized with any one of the wavelength multiplexed light.

Preferably, the optical input means has an optical branching circuit or an optical demultiplexing circuit, and the wavelength of the wavelength is transmitted from an end face other than the optical output end face of the array laser light source via the optical branching circuit or the optical demultiplexing circuit. By injecting the multiplex light, the wavelength of the array laser light source is synchronized with any one of the wavelength multiplex lights.

Preferably, the wavelength-stabilized wavelength light of the array laser light source is output from the optical circulator.

Preferably, each wavelength light is output from the light output end face of the wavelength-stabilized array laser light source.

Preferably, the array laser light source is a device in which a plurality of array semiconductor lasers and an optical branching circuit or an optical demultiplexing circuit are integrated.

Preferably, the wavelength multiplexing light generating means includes a plurality of semiconductor lasers for generating a plurality of wavelength lights, and a multiplexing means for multiplexing the plurality of wavelength lights generated from the plurality of semiconductor lasers. Branching means for branching the wavelength multiplexed light output from the multiplexing means, and controlling the wavelengths of the plurality of semiconductor lasers based on an error amount between the wavelength multiplexed light and the reference wavelength light branched by the branching means. Wavelength monitoring means.

Preferably, the wavelength-division multiplexing light generating means is constituted by an optical frequency comb generator.

Preferably, the optical frequency comb generator includes a mode-locked laser that outputs light at a predetermined frequency interval, and a free spectral range frequency of the mode-locked laser or a frequency division or multiplication frequency of the free spectral range. A signal source for generating a signal, means for superimposing and applying a signal output from the signal source to a reverse bias voltage of the mode-locked laser, and a reference light equal to a multiplication frequency of a free spectral range of the mode-locked laser. A frequency-stabilized light source to be output; and means for inputting the reference light to the mode-locked laser and performing injection locking.

Preferably, the apparatus further comprises a wavelength selection element for selectively outputting a plurality of or one wavelength light from the wavelength stabilized array laser light source.

Preferably, the wavelength selecting element is
An acousto-optic filter or an arrayed waveguide grating.

Preferably, the wavelength selecting element is
An optical switch or a combination of an optical demultiplexing circuit and the optical switch.

In the present invention, the wavelength of the wavelength multiplexed light is adjusted by injecting the wavelength multiplexed light stabilized in advance with high accuracy by the wavelength multiplexed light generating means into the array laser light source through the light input means. In this case, wavelength multiplexed light or a plurality of single-wavelength lights are taken out by the optical output means, so that the wavelength can be controlled to the specified wavelength of the optical path network. Only the stabilization of the wavelength multiplexed light input is required, and no electrical control circuit is required, and the wavelength of the array laser light source can be controlled with high accuracy with a simple configuration.

According to the present invention, the wavelength multiplexed light generating means multiplexes the output wavelengths of a plurality of semiconductor lasers and inputs a part of the output wavelengths to a wavelength monitoring circuit. By performing wavelength control with negative feedback to the control circuit, the control circuit can be made economical in a device such as an optical cross-connect and the size can be reduced.

Further, according to the present invention, the wavelength multiplexing generating means is constituted by an optical frequency comb generator, so that the size can be further reduced, and the wavelength multiplexing generating circuit can be made more economical.

Further, in the present invention, by selectively outputting a plurality of or only one wavelength light from a wavelength stabilized array laser light source via a wavelength selection element, light having an arbitrary number of wavelengths out of a specified wavelength is obtained. This makes it possible to cope with a system in which light of a desired wavelength changes depending on an operation state.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows a schematic configuration of a wavelength stabilizing device for an array laser light source according to a first embodiment of the present invention. In FIG. 1, a wavelength multiplexed light generating circuit 101 multiplexes a plurality of wavelength lights to generate a wavelength multiplexed light which is stabilized with high accuracy in advance. The wavelength multiplexed light, which has been stabilized in advance with high accuracy, emitted from the wavelength multiplexing light generation circuit 101 is injected into the array laser light source 103 via the light input / output means 102 as light injection means.

An example of the array laser light source 103 is a DFB-LD array in which a plurality of DFB (distributed feedback) semiconductor lasers (DFB-LD) are integrated. The wavelength characteristics of the DFB-LD slightly change with temperature / injection current (about 10G
Hz / ° C, about 1 GHz / mA).

At the time of wavelength stabilization, the temperature / injection current is set to a value so as to be approximately in the vicinity of the specified wavelength. At this time, if the wavelength-division multiplexed light set to the specified wavelength is injected into the DFB semiconductor laser that is the array laser light source 103, the difference between one wavelength of the wavelength-division multiplexed light and the wavelength of the semiconductor laser becomes the drawing width (wavelength). When the wavelength falls within the wavelength interval of the multiplexed light, the oscillation wavelength of the DFB semiconductor laser is close to one wavelength of the injection wavelength multiplexed light (the wavelength oscillated before the light injection is performed) due to the injection locking phenomenon. To one of the wavelength multiplexed lights). The synchronized wavelength-multiplexed light or a plurality of single-wavelength lights are extracted by the optical input / output means 102.

As described above, in the present embodiment, the wavelength multiplexed light stabilized in advance with high accuracy is
03, the array laser light source 103
Is synchronized with the wavelength of the wavelength division multiplexed light,
02 extracts wavelength-multiplexed light or a plurality of single-wavelength lights. For this reason, the wavelength stabilization of the array laser light source 103 is only required to stabilize the wavelength multiplexed light input, and no electrical control circuit is required, and the wavelength of the array laser light source can be controlled with high accuracy with a simple configuration.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.
1 shows a schematic configuration of a wavelength stabilizing device for an array laser light source according to the embodiment. In this embodiment, an optical circulator 104 and an optical branching circuit or an optical demultiplexing circuit 105 are used as the optical input / output means 102. An optical splitter or the like can be used as the optical branching circuit, and a diffraction grating or an arrayed waveguide grating can be used as the optical branching circuit.

The wavelength-division multiplexed light generated from the wavelength-division multiplexed light generation circuit 101 is passed through a circulator 104 and an optical branching circuit or an optical demultiplexing circuit 105 to an array laser light source 103
In this case, the wavelength of the array laser light source 103 is synchronized with any one of the wavelength multiplexed lights, and the synchronized wavelength is output from the circulator 104.

(Third Embodiment) FIG. 3 shows a third embodiment of the present invention.
1 shows a schematic configuration of a wavelength stabilizing device for an array laser light source according to the embodiment. In this embodiment, an optical branching circuit or an optical demultiplexing circuit 105 is used as the means for injecting wavelength-division multiplexed light.
Is used.

The wavelength-division multiplexed light generated from the wavelength-division multiplexing light generating circuit 101 is injected into the array laser light source 103 through an optical branching circuit or an optical demultiplexing circuit 105 from an end face other than the output end face of the light source, thereby providing an array laser light source. The wavelength 103 is synchronized with any one of the wavelength multiplexed lights, and the synchronized wavelength is output from the other end face of the array laser light source 103.

When an optical branch circuit is used as 105, it is preferable to use a laser having a filter characteristic, for example, a DFB-LD or DBR (distributed black reflection) -LD as the array laser light source 103.

(Fourth Embodiment) FIG. 4 is a block diagram showing a fourth embodiment of the present invention, and FIG. 5 shows its output characteristics. The present embodiment is an array-type semiconductor laser [Reference Document 2] in which the array laser light source 103 shown in FIGS. 1 to 3 is configured by a device in which a plurality of semiconductor lasers and an optical demultiplexing circuit are integrated. An example of the configuration in the case is shown. Other components are the same as those shown in FIGS.

[Reference 2] R. Monnard, M. Zirngibl,
CRDoerr, CHJoyner, and LwStulz, "Demonstrati
on of an eight-wavelength fast packet switching tr
ansmitter of 2.5 ‐Gb / s bit stream, `` IEEE Photonic
s Tech. Lett., vol. 10, no. 3, pp. 430-431, 1998. In FIG. 4, reference numeral 120 denotes an optical fiber, 121 denotes an incident end face, 122 denotes an optical amplifier, and 123 denotes a free space region (slab waveguide). ), 124 are waveguide gratings, 125 is a free space region (slab waveguide), 126 is an optical amplifier, and 127 is an emission end face.

This array type semiconductor laser has a configuration in which a semiconductor optical amplifier is integrated in optical demultiplexing circuits 123 to 125, and has a resonator structure formed by reflectors at an input end face 121 and an output end face 127, and a semiconductor optical amplifier as a gain medium. 122, 1
26 is a laser configuration. Optical fiber 120
As shown in FIG. 5, a wavelength multiplexed light having an eight-channel line spectrum is emitted from the emission end face 12 by a resonance phenomenon in which the laser light introduced from the light source is repeatedly reflected between the reflectors on both end faces.
7 The operating principle is the same as that of the array laser light source 103 shown in FIGS. The operation of the entire apparatus is the same as in the above-described first to third embodiments.

(Fifth Embodiment) FIGS. 6, 7 and 8 are configuration diagrams showing a fifth embodiment of the present invention.
This embodiment exemplifies a case where the wavelength division multiplexing generation circuit 101 shown in FIGS. 1, 2 and 3 includes a plurality of semiconductor lasers 210, a wavelength monitoring circuit 240, a multiplexing unit 220 and a branching unit 230. I do. The other components are the same as those shown in FIGS. 1 to 3, and a description and illustration thereof will be omitted.
Also, the operation of the entire apparatus is the same as in the above-described first to third embodiments, and a description thereof will be omitted.

As shown in FIG. 6, the output wavelengths of a plurality of semiconductor lasers (wavelength stabilized light sources) 210 are
And a part thereof is input to the wavelength monitoring circuit 240 via the coupler 230. The wavelength monitoring circuit 240 performs wavelength control by negatively feeding back the error amount from the specified wavelength to the semiconductor laser 210 by the wavelength control circuit 250. In this way, the outputs of the plurality of semiconductor lasers 210 are
The wavelength multiplexed light source controlled in wavelength by 40 is used as wavelength multiplexed light, and one wavelength multiplexed light source is provided in an optical cross-connect device (not shown) and distributed to a plurality of array laser light sources to reduce the size. It becomes possible.

More specifically, the wavelength monitoring circuit 240 shown in FIG. 6 includes an arrayed waveguide grating (AWG) 242 described later,
Temperature control circuit 246 and photoelectric conversion / amplification circuit 2 described later
48 and the like. The photoelectric conversion / amplification circuit 248 includes, for example, a photodiode (PD) and a logarithmic amplifier (Log. Am).
p). The wavelength control circuit 250 includes a phase comparison circuit 252 for obtaining an error amount from a specified wavelength, a feedback path filter (feedback filter) 254, a digital / analog (D / A) converter 256, a personal computer 258, and the like. Note that the D / A converter 256 is inserted in the case of digital control, and that the wavelength control circuit 250 is configured by analog control.
56 is not required.

A plurality of wavelength lights output from a plurality of semiconductor lasers constituting the wavelength stabilizing light source 210 are transmitted to the optical multiplexer 22.
The multiplexed light is input to the wavelength monitoring circuit 240 via the coupler 230. The wavelength monitoring circuit 240 performs wavelength control by negatively feeding back the error amount from the specified wavelength to the semiconductor laser of the wavelength stabilizing light source 210 by the wavelength control circuit 250.

FIGS. 7 and 8 show the contents of the arrayed waveguide grating 242 and the temperature control circuit 246 of FIG. 6 in detail.

First, in FIG. 7, the reference wavelength light (wavelength λ 0) from the reference light source 244 and the wavelength-division multiplexed light (the wavelengths λ 1 to λn) to be monitored from the coupler 230 are transmitted to the wavelength monitoring circuit 2.
The multiplexed light is multiplexed by the optical coupler 211 in the optical waveguide 42 and is input to a predetermined input waveguide of the arrayed waveguide grating 242. The arrayed waveguide grating 242 includes an input waveguide array 232 formed on a substrate 231, an input-side concave slab waveguide 233,
An arrayed waveguide 234 composed of a plurality of waveguides which are sequentially elongated by a waveguide length difference ΔL, an output-side concave slab waveguide 2
35, a configuration in which output waveguide arrays 236 are sequentially connected. In this example, a heater 213 is attached to the arrayed waveguide 234. The reference signal Sa output from the oscillator 214 is input to the current circuit 215 and controls the temperature of the heater 213.

Output waveguide # 0 of arrayed waveguide grating 242
To #n are connected to photodetectors 216-0 and 216-i (i is 1 to n) constituting the photoelectric conversion / amplification circuit 248 (FIG. 8A). These photodetectors 216-0,216
The output of -i is connected to the phase comparators 252-0, 252-i via the amplifiers 217-0, 217-1 constituting the photoelectric conversion / amplification circuit 248, respectively. Phase comparator 25
Reference signals Sa output from the oscillator 214 are input to 2-0 and 252-i, and the outputs are input to low-pass filters (LPF) 254-0 and 254-i, respectively. The output of the low-pass filter 254-0 is the integrator 260
Input to −0. A temperature control circuit 246 is connected to the output of the integrator 260-0. The temperature control circuit 246 controls a Peltier cooler (Peltier element) 222 that adjusts the temperature of the arrayed waveguide grating 242. The phase comparator 252-0, the low-pass filter 254-0, and the integrator 26
0-0 is a personal computer 25 as shown in FIG.
8 can be replaced.

(Sixth Embodiment) FIGS. 9 and 10 are configuration diagrams showing a sixth embodiment of the present invention. This embodiment exemplifies a case where the wavelength division multiplexing generation circuit 101 shown in FIGS. 1, 2 and 3 is constituted by an optical frequency comb generator. In this example, it is possible to further reduce the size as compared with the case of the above-described fifth embodiment. The other components are the same as those shown in FIGS. 1 to 3, and a description and illustration thereof will be omitted. Also, the operation of the entire apparatus is the same as in the above-described first to third embodiments, and a description thereof will be omitted.

FIG. 9 shows the structure of the optical frequency comb generator.
The optical frequency comb generator includes a synthesizer 352, an amplifier 353, a bias tee 354, and a mode-locked laser 35.
And a frequency-stabilized light source 311 for outputting a reference light having an optical frequency of a frequency multiplied by the free spectrum range of the mode-locked laser 351, and the reference light fs is subjected to a mode through an optical attenuator 312 and an optical circulator 313 The configuration is such that it is inputted to the synchronous laser 351 and injection-locked. The optical attenuator 312 is for adjusting the reference light to the optical power required for injection locking. If the frequency stabilized light source 311 has an appropriate optical power, the optical attenuator 312 is You may omit it.

FIG. 10 shows an example of the internal configuration of the frequency stabilized light source 311. In FIG. 10, the semiconductor laser 32
1 is the frequency fs which is the output of the frequency stabilized light source 311
The reference light is output. The semiconductor laser 322 is controlled by the gas cell 323, the photodetector 324, and the control circuit 325, and outputs an absolute frequency reference light having a frequency fm whose frequency is stabilized to an absorption line of a molecule or an atom. The reference light having the frequency fs and the absolute frequency reference light having the frequency fm are multiplexed by the multiplexer 326 and converted into an electric signal by the photodetector 327. At this time, the difference frequency | fm−fs | between them is detected as a beat signal.

On the other hand, the signal source 328 generates a frequency signal having a difference frequency f0 = | fm-fs '| between the absolute frequency fm and the multiplied frequency fs' of the free spectrum range of the mode-locked laser.

The frequency / phase comparator 329 is connected to the photodetector 3
27 and the frequency | f of the signal of frequency f0 output from the signal source 328.
The frequency difference and the phase of the signal of m-fs '| are compared, and a signal error (|| fm-fs' | -f0 |) is output. The control circuit 330 negatively feeds back the error signal to the drive circuit of the semiconductor laser 321 so that the error signal becomes zero, that is, the frequency fs of the semiconductor laser 321 is an integral multiple of the free spectrum range of the mode-locked laser ( f
s').

In such a configuration, by inputting the reference light having an integral multiple of the free spectrum range and a high spectral purity to the mode-locked laser 351, one oscillation mode of the mode-locked laser 351 is drawn to the frequency of the reference light. And the other modes (including the reference light) are stabilized at a strict frequency.

As shown in FIG. 11, the output light spectrum obtained by the above configuration has a spectrum shape in which a line spectrum stands at a frequency multiplied by the modulation frequency or a frequency interval of the free spectrum range of the resonator. FIG. 11 shows a measurement of the optical spectrum at the time of injection locking, and the frequency of the reference light for injection locking is 193.100.
At THz, the optical power is -26 dBm.

As described above, the mode-locked laser 351 injection-locked with the reference light generates a comb with a free spectrum range interval including the frequency of the reference light, and generates a relatively flat optical spectrum particularly over a wide range. be able to.

(Seventh Embodiment) FIGS. 12, 13, 14 and 15 are configuration diagrams showing a seventh embodiment of the present invention.

In the present embodiment, in the configuration shown in the first to sixth embodiments of the present invention, the wavelength-selective element (for example, an acousto-optic filter, A configuration in which only a plurality of or only one wavelength light is selectively output via an arrayed waveguide grating or the like will be exemplified.

For example, as shown in FIGS.
The wavelength selection element 106 is disposed for output light (wavelength multiplexed light or a plurality of wavelength lights). That is, FIG.
In the case of 2, the wavelength selection element 106 is arranged for the wavelength multiplexed light that is the output light of the optical circulator 104,
A plurality of or one wavelength light is selected from the wavelength multiplexed light by the wavelength selection element 106 and output as output light.

In the case of FIG. 13, the wavelength selecting element 106 is disposed for each wavelength light output output from the array laser light source 103, and the wavelength selecting element 106 separates a plurality of or one wavelength from each wavelength light output. Light is selected and output as output light.

As a function of the wavelength selection element 106, for example, when an acousto-optic filter is used, it is possible to take out one or a plurality of wavelengths of wavelength multiplexed light.

Further, embodiments other than the acousto-optic filter are shown in FIGS. FIG. 14 shows a configuration in which the wavelength division multiplexed light is demultiplexed into each wavelength light by using the optical demultiplexing circuit 107, and one or a plurality of wavelength lights are extracted from each wavelength light by the optical switch 108. As the optical switch 108, an arrayed waveguide grating, a bulk electronic switch, a planar waveguide electronic switch, or the like can be used.

FIG. 15 shows a configuration in which an optical switch 108 is provided for each of a plurality of wavelength light outputs, and one or a plurality of wavelength lights are extracted by the optical switch 108.

As described above, by providing the function of selecting a plurality of or one wavelength light from the wavelength lights stabilized by the method of stabilizing the array laser light source 103, the desired wavelength light changes depending on the operation state. It is possible to cope with a system that does.

The operation of the entire apparatus is the same as that of the first to the above.
Since the third embodiment is the same as the third embodiment, the description is omitted.

[0064]

As described above, according to the present invention,
The following effects are obtained.

(1) The wavelength of the wavelength multiplexed light is converted into the wavelength of the wavelength multiplexed light by injecting the wavelength multiplexed light stabilized in advance with high accuracy by the wavelength multiplexed light generating means into the array laser light source through the light input means. Synchronization is performed so that wavelength multiplexed light or a plurality of single-wavelength lights are extracted by the optical output means, so that the wavelength can be controlled to the specified wavelength of the optical path network. Further, the wavelength stabilization of the array laser light source is only required to stabilize the wavelength multiplexed light input, and no electrical control circuit is required, and the wavelength of the array laser light source can be controlled with high accuracy by a simple configuration.

(2) The output wavelengths of a plurality of semiconductor lasers are multiplexed as wavelength multiplexed light generating means, and a part of the output wavelengths is input to a wavelength monitoring circuit, and the wavelength monitoring circuit negatively feeds back the error amount from the specified wavelength to the semiconductor laser. By performing wavelength control in such a manner, the control circuit can be made economical in a device such as an optical cross-connect, and the size can be reduced.

(3) By configuring the wavelength multiplexing generation means with an optical frequency comb generator, it is possible to further reduce the size and to achieve economical use of the wavelength multiplexing generation circuit.

(4) By selectively outputting a plurality of or only one wavelength light from the wavelength-stabilized array laser light source via the wavelength selection element, light having an arbitrary number of wavelengths out of the specified wavelength can be obtained. Also, it is possible to cope with a system in which light of a desired wavelength changes depending on an operation state.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a wavelength stabilizing device of an array laser light source according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of a wavelength stabilizing device of an array laser light source according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a schematic configuration of a wavelength stabilizing device of an array laser light source according to a third embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a configuration example of an array-type semiconductor laser in which an array laser light source is configured by a device in which a plurality of semiconductor lasers and an optical demultiplexing circuit are integrated according to a fourth embodiment of the present invention. .

FIG. 5 is a graph showing output characteristics of the array type semiconductor laser of FIG. 4;

FIG. 6 is a block diagram illustrating a configuration example of a wavelength division multiplexing light supply module when a wavelength division multiplexing generation circuit is configured by a plurality of semiconductor lasers, a wavelength monitoring circuit, and a multiplexing unit according to a fifth embodiment of the present invention. is there.

FIG. 7 is a block diagram illustrating a detailed configuration example of the wavelength monitoring circuit of FIG. 6;

8A is a diagram showing a configuration of a main part of FIG. 7, and FIG.
FIG. 8 is a diagram showing a configuration of a main part of a modification of FIG. 7.

FIG. 9 is a block diagram illustrating a configuration example of an optical frequency comb generator when a wavelength division multiplexing generation circuit according to a sixth embodiment of the present invention is configured by an optical frequency comb generator.

FIG. 10 is a block diagram showing a configuration example of a frequency stabilized light source used in the optical frequency comb generator of FIG.

FIG. 11 is a graph showing a measurement result of an optical spectrum of the optical frequency comb generator of FIG. 9;

FIG. 12 is a block diagram illustrating an example of a configuration of a wavelength stabilizing device using a wavelength selection element according to a seventh embodiment of the present invention.

FIG. 13 is a block diagram showing another example of the configuration of the wavelength stabilizing device using the wavelength selection element according to the seventh embodiment of the present invention.

FIG. 14 is a block diagram illustrating an example of a configuration using an optical switch as a wavelength selection element according to a seventh embodiment of the present invention.

FIG. 15 is a block diagram showing another example of a configuration using an optical switch as a wavelength selection element according to the seventh embodiment of the present invention.

FIG. 16 is a block diagram illustrating a configuration example of a conventional wavelength monitoring device.

FIG. 17 is a waveform chart showing the operation of the conventional wavelength monitoring device.

FIG. 18 is a graph showing that the amount of displacement of the piezoelectric element with respect to the voltage has a hysteresis characteristic.

DESCRIPTION OF SYMBOLS 101 Wavelength multiplexing light generating circuit 102 Optical input / output means 103 Array laser light source 104 Optical circulator 105 Optical branching circuit or optical demultiplexing circuit 106 Wavelength selecting element 107 Optical demultiplexing circuit 108 Optical switch 121 Incident end face 122 Optical amplifier 123 free space region (slab waveguide) 124 waveguide grating 125 free space region (slab waveguide) 126 optical amplifier 127 emission end face 210 wavelength stabilized light source (plural semiconductor lasers) 211 optical coupler 213 heater 214 oscillator 215 current circuit 216 −0,216-i Photodetector 217-0,217-1 Amplifier 220 Optical multiplexer 222 Peltier cooler (Peltier element) 223 Optical switch 230 Coupler 231 Substrate 232 Input waveguide array 233 Input concave slab waveguide 234 Ray waveguide 235 Output side concave slab waveguide 236 Output waveguide array 240 Wavelength monitoring circuit 242 Array waveguide grating (AWG) 243 Array waveguide 246 Temperature control circuit 248 Photoelectric conversion / amplification circuit 250 Wavelength control circuit 252, 252 0,252-i Phase comparator 254 Feedback path filter 254-0,254-i Low pass filter 256 Digital analog (D / A) converter 258 Personal computer 260-0 Integrator 311 Frequency stabilized light source 312 Optical attenuator 321 Semiconductor Laser 322 semiconductor laser 323 gas cell 325 control circuit 326 multiplexer 327 photodetector 328 signal source 329 frequency / phase comparator 324 photodetector 330 control circuit 351 mode-locked laser 352 synthesizer 353 amplifier 354 Bias tee

Claims (12)

[Claims] 1. A wavelength multiplexing light generating means for generating wavelength multiplexing light obtained by multiplexing a plurality of wavelength lights stabilized in advance with high accuracy, and an array laser for generating the wavelength multiplexing light generated from the wavelength multiplexing light generating circuit. Light input means for synchronizing the wavelength of the array laser light source with the wavelength of the wavelength multiplexed light by injecting the light into the light source; and light for extracting wavelength multiplexed light or a plurality of single wavelength lights from the wavelength stabilized array laser light source. A wavelength stabilizing device for an array laser light source, comprising: an output unit. 2. An optical circulator and an optical branching circuit or an optical demultiplexing circuit as the optical input means and the optical output means, and the wavelength multiplexed light is generated via the optical circulator and the optical branching circuit or the optical demultiplexing circuit. 2. The method according to claim 1, wherein the wavelength of the array laser light source is synchronized with any one of the wavelength multiplexed lights by injecting the wavelength multiplexed light generated by the means into the array laser light source. Array laser light source wavelength stabilization device. 3. An optical input circuit comprising an optical branching circuit or an optical demultiplexing circuit as the optical input means, wherein the wavelength-division multiplexed light is transmitted from an end face other than the optical output end face of the array laser light source via the optical branching circuit or the optical demultiplexing circuit. 2. The wavelength stabilizing device for an array laser light source according to claim 1, wherein the wavelength of the array laser light source is synchronized with any one of the wavelength multiplexed lights by injection. 4. The wavelength stabilizing apparatus for an array laser light source according to claim 2, wherein the wavelength stabilized wavelength light of the array laser light source is output from the optical circulator. 5. The wavelength stabilizing device for an array laser light source according to claim 3, wherein each wavelength light is output from a light output end face of the wavelength stabilized array laser light source. 6. The device according to claim 1, wherein the array laser light source is constituted by a device in which a plurality of array semiconductor lasers and an optical branching circuit or an optical demultiplexing circuit are integrated. Array laser light source wavelength stabilizing device. 7. The wavelength multiplexing light generating means, a plurality of semiconductor lasers for generating a plurality of wavelength lights, a multiplexing means for multiplexing a plurality of wavelength lights generated from the plurality of semiconductor lasers, Branching means for branching the wavelength multiplexed light output from the wave means, and wavelength monitoring means for controlling the wavelengths of the plurality of semiconductor lasers based on an error amount between the wavelength multiplexed light and the reference wavelength light branched by the branching means. 7. The wavelength stabilizing device for an array laser light source according to claim 1, wherein: 8. The apparatus according to claim 1, wherein said wavelength multiplexing light generating means is constituted by an optical frequency comb generator.
7. The wavelength stabilizing device for an array laser light source according to any one of claims 6 to 6. 9. An optical frequency comb generator, comprising: a mode-locked laser that outputs light at a predetermined frequency interval; and a signal having a free spectral range frequency of the mode-locked laser or a frequency division or multiplication frequency of the free spectral range. A signal source to be superimposed, a signal output from the signal source being superimposed on a reverse bias voltage of the mode-locked laser, and a means for outputting a reference light equal to a multiple frequency of a free spectral range of the mode-locked laser. 9. The wavelength stabilizing device for an array laser light source according to claim 8, comprising: a stabilizing light source; and means for inputting the reference light to the mode-locked laser and performing injection locking. 10. The array laser light source according to claim 1, further comprising a wavelength selection element for selectively outputting a plurality of or one wavelength light from the wavelength-stabilized array laser light source. Wavelength stabilizer. 11. The wavelength stabilizing device for an array laser light source according to claim 10, wherein the wavelength selection element is an acousto-optic filter or an arrayed waveguide grating. 12. The wavelength stabilizing device for an array laser light source according to claim 10, wherein the wavelength selecting element is an optical switch or a combination of an optical demultiplexing circuit and the optical switch.