JPH04136826A - Wavelength synchronization type optical wavelength selection filter - Google Patents

Abstract

PURPOSE:To make contribution to the realization of the wavelength multiplex transmission network utilizing the multiplexing degree of wavelengths by realizing the wavelength synchronization type optical wavelength selection filter which outputs the wavelength of the light outputted as a result of a wavelength selection transmission operation as a stable wavelength which is free from fluctuations. CONSTITUTION:The respective wavelengths are separated by one wavelength selection filters 102-1 to 102-n from the reference wavelength light group outputted by a reference wavelength light group generating section 7 and are inputted together with the light signals distributed by 1Xn optical star couplers 103 into wavelength conversion semiconductor lasers 1-1 to 1-n, by which only the light signal having a desired wavelength is selectively transmitted from the light signals distributed by the 1Xn optical star couplers 103. The oscillation conditions of the wavelength conversion semiconductor lasers 1-1 to 1-n are equaled to the wavelength of the inputted reference wavelength light, by which the light signal having this light wavelength is selectively transmitted and this light wavelength is outputted as stable wavelength having the fluctuation approximately equal to the fluctuation of the reference wavelength light.

Description

[Detailed Description of the Invention] [Summary] Regarding a wavelength selection filter that selects an optical signal of a specific wavelength from a plurality of optical signals having different wavelengths, the output has small fluctuation even when the wavelength of the input optical signal fluctuates. The purpose of the present invention is to provide a wavelength-synchronized optical wavelength selection filter that can generate an optical signal with a stable wavelength, and includes a wavelength conversion semiconductor laser, a control unit that controls the oscillation wavelength of the wavelength conversion semiconductor laser, and a wavelength fluctuation a reference wavelength light generating section that generates a reference wavelength light having a small and stable wavelength;
A wavelength multiplexed optical signal consisting of optical signals of a plurality of different wavelengths is inputted to the wavelength conversion semiconductor laser from the signal light input section, and a reference wavelength light having a specific wavelength in the wavelength multiplexed optical signal is inputted from the reference wavelength light generation section. At the same time, the control section controls the oscillation wavelength of the wavelength conversion semiconductor laser to be the same wavelength as the reference wavelength light, so that the wavelength conversion semiconductor laser converts the optical signal of a specific wavelength in the wavelength multiplexed optical signal. In response to this, the optical signal is converted into light having a stable wavelength with small wavelength fluctuation synchronized with the reference wavelength light, and outputted.

[Industrial application field]

The present invention relates to a wavelength selection filter that selects an optical signal of a specific wavelength from among a plurality of optical signals having different wavelengths that are multiplexed on a wavelength axis, and in particular, the present invention relates to a wavelength selection filter that selects an optical signal of a specific wavelength from among a plurality of optical signals that are multiplexed on a wavelength axis and have different wavelengths, and in particular, the present invention This invention relates to a wavelength-synchronized optical wavelength selection filter that outputs light in synchronization with the wavelength of light.

BACKGROUND OF THE INVENTION With the development of optical communication network technology, various studies are being conducted on optical signal exchange systems, such as optical switching five-optical subscriber systems.

Among them, one of the features of optical fiber transmission system, broadband property, that is, the ability to handle optical signals of multiple frequencies or multiple wavelengths at the same time, can be utilized for example to connect and exchange subscribers and terminals. A wavelength multiplexing type optical communication system has been proposed, which allocates optical wavelengths according to the destination, converts the wavelength of the optical signal according to the destination, and transmits the signal.

In an optical wavelength division multiplexing communication system, an optical wavelength selection filter is required that has a characteristic that allows an optical signal of a desired wavelength to be freely selected from among wavelength multiplexed optical signals.

Such an optical wavelength selection filter selectively transmits only an optical signal of a specific wavelength among multiple optical signals having wavelengths close to each other that are multiplexed on the wavelength axis, and also selectively transmits the optical signal of a specific wavelength. It is desired that the output wavelength has a predetermined wavelength and is stable so that it can be distinguished from optical signals of other wavelengths.

[Conventional technology]

Fig. 16(a), (b) and Fig. 17(a), (
b) shows a conventional optical wavelength selection filter.

FIGS. 16(a) and (b) show a phase-controlled DFB semiconductor laser, and FIGS. 17(a) and (b) show a phase-shift controlled DFB semiconductor laser. In both figures, (a) is a schematic diagram. Figure, (b) shows a perspective view. These have an active layer 201 and a light guide layer 202, each with a current of 1. , Ip are caused to flow, thereby forming an active region 203 and a phase control region 204.

These wavelength selection filters utilize semiconductor laser technology to introduce a diffraction grating structure into the active layer or optical guide layer of a semiconductor laser amplifier. The gain for light is made larger for light of a specific wavelength among the input light.

In addition, by introducing a diffraction grating structure into the internal structure, it has a phase control region that changes the refractive index by injecting a current so that the phase of the input light is optimal with respect to the period of the diffraction grating. be.

[Problem to be solved by the invention]

Fig. 16(a), (b) and Fig. 17(a), (
The optical wavelength selection filter shown in b) outputs light at the wavelength with the highest transmittance without changing the wavelength of the input light, so that it functions as a wavelength selection filter. I have to.

Therefore, if the wavelength of the input light fluctuates around the set wavelength, the fluctuation will be preserved and transmitted to the next stage optical transmission system.

Therefore, for example, for light of a specific wavelength among a large number of optical signals having mutually different wavelengths that are multiplexed on the wavelength axis, a wavelength selection filter is used to selectively transmit the light of that wavelength. When sending the light to the next stage transmission system, the wavelength fluctuation of the light is preserved.

If each wavelength of the input wavelength multiplexed optical signal is unstable in this way, the output wavelength of the wavelength selection filter will also be unstable, which will affect the operation of the subsequent stages. Specifically, level fluctuations occur when the input optical wavelength deviates from the peak of the transmission spectrum, and inter-wavelength crosstalk occurs in the output channel because the interval between wavelengths differs from a set value.

To avoid such problems, each wavelength on the input side must be highly stable, but a light source with highly stable wavelengths would be systemically complex, so large-scale wavelength multiplexing would be required. In the system, a problem arises in that the control system becomes enormous.

The present invention aims to solve the problems of the prior art, and is to generate an output optical signal having a stable wavelength with small fluctuation even when the wavelength of the input optical signal fluctuates. The purpose of the present invention is to provide a wavelength-synchronized optical wavelength selective filter that can perform the following steps.

[Means to solve the problem]

Figures 1 to 4, Figures 5 (a) to (d), Figure 6 (
a) ~(C).

Figures 7(a) to (C), Figures 8(a) to (d)
, FIGS. 9(a) to 9(c) show the basic structure of the present invention.

As shown in FIG. 1, the basic configuration of the present invention is such that when a signal light is inputted, it is converted into light having a wavelength different from that of the signal light and output by a wavelength conversion semiconductor laser 1.
The control section 3 controls the oscillation wavelength of the wavelength conversion semiconductor laser 1, and the reference wavelength light generation section 4 is configured to generate reference wavelength light having a stable wavelength with little wavelength fluctuation. A wavelength-multiplexed optical signal consisting of a plurality of wavelength-multiplexed optical signals each having a different wavelength is input from the signal light input section 2 to the wavelength conversion semiconductor laser 1, and from the reference wavelength light generation section 4, the wavelength-multiplexed optical signal is A reference wavelength light having a specific wavelength is input to the wavelength conversion semiconductor laser 1 from the reference wavelength light input section 5, and the oscillation wavelength of the wavelength conversion semiconductor laser is made to be the same wavelength as this reference wavelength light in the control section 3. As a result, the wavelength conversion semiconductor laser 1 selectively responds to an optical signal of a specific wavelength in a wavelength multiplexed optical signal, and converts this optical signal into light of a stable wavelength with small wavelength fluctuation synchronized with the reference wavelength light. The signal light is converted and outputted from the signal light output section 6.

Further, as shown in FIG. 2, the present invention uses a reference wavelength light group generator 7 to generate a plurality of stable wavelengths with small wavelength fluctuations among different wavelengths including a specific wavelength in a wavelength multiplexed optical signal. The reference wavelength light generating unit outputs a reference wavelength light group consisting of light of 4.

Further, as shown in FIG. 3, the present invention uses a reference wavelength light group generator 7 to generate a plurality of stable wavelengths with small wavelength fluctuations among different wavelengths including a specific wavelength in a wavelength multiplexed optical signal. By outputting a reference wavelength light group consisting of light of
A reference wavelength light generating section 4 is configured.

Further, as shown in the principle configuration of FIG. The reference wavelength light group generating section 7 is constructed by merging the lights generated by the wavelength stabilized light sources 101 to 10-n.

Further, in the present invention, as shown in FIGS. 5(a) to 5(d), a sweep signal is generated by a sweep signal source 12, and a sweep type wavelength tunable light source 13 is used to generate a sweep signal according to the sweep signal. An optical signal whose wavelength changes continuously over time by sweeping on the wavelength axis is generated, and an optical interferometer 14 extracts from the light generated by the swept wavelength tunable light source 13 a wavelength corresponding to its transmission peak wavelength. The reference wavelength light group generating section 7 is configured by generating only light discretely on the time axis and by making the transmission peak wavelength of the optical interferometer 14 form a desired reference wavelength group. It is.

Further, in the present invention, as shown in FIGS. 6(a) to 6(C), the optical interferometer 14 is a Fapley-Perot interferometer, a Matsuha-Zehnder interferometer, or a ring interferometer. Which of them is one?

Further, in the present invention, as shown in FIGS. 7(a) to (C), the driving circuit 15 generates a driving signal, and the optical switch or optical gate 16 uses this driving signal to fix the optical wavelength. The fixed optical wavelength selection filter 8 or the variable optical wavelength selection filter 9 is configured by separating only the optical signal of one desired wavelength from the output light of the selection filter 8 or the variable optical wavelength selection filter 9 on the time axis. This is what I did.

Further, as shown in FIGS. 8(a) to 8(d), the present invention generates a sweep signal by a sweep signal source 12, and a sweep type wavelength tunable light source 13 generates a sweep signal according to the sweep signal. An optical signal whose wavelength changes continuously over time by sweeping on the wavelength axis is generated, and an interference-type optical wavelength selection filter 17 selects a signal from the light generated by the swept-type wavelength tunable light source 13 that matches the transmitted peak light wavelength. The reference wavelength light generating section 4 is constructed by discretely generating only light having the wavelengths determined on the time axis.

Further, the present invention provides a configuration in which the interference type optical wavelength selection filter 17 is provided with any one of a Fapley-Perot type interferometer, a Matsuha-Zehnder type interferometer, or a ring type interferometer as a optical interferometer. This is what I did.

Further, as shown in FIG. 9(a), the present invention is provided with an optical coupler 18, and the signal light inputted from the signal light input section 2 and the reference wavelength light generated in the reference wavelength light generation section 4 are connected to each other. The reference wavelength light inputted from the optical input section 5 is combined with the reference wavelength light, and this combined light is inputted into the wavelength conversion semiconductor laser 1.

Further, as shown in FIG. 9(b), the present invention is provided with a polarizing beam splitter 19, and one input terminal of the polarizing beam splitter 19 is used as the signal light input section 2 to convert the signal light into TM polarized light. The other input terminal of the polarization beam splitter 19 is used as a reference wavelength light input section 5 to input the reference wavelength light as TE polarized light into the wavelength conversion semiconductor laser 1.

Further, as shown in FIG. 9C, the present invention is provided with a polarizing beam splitter 19, and one terminal of the polarizing beam splitter 19 is used as a signal light input section 2 to input signal light. The output light from the other terminal is input as TM polarized light into one end face of the wavelength conversion semiconductor laser 1, and the oscillation output light of this wavelength conversion semiconductor laser 1 is taken out from the same end face and sent to the other end of the polarizing beam splitter 19 as TE polarized light. The terminal on the opposite side of the polarizing beam splitter 19 is outputted as a signal light output section 6, and the other end face of the wavelength conversion semiconductor laser l is used as a reference wavelength light input section 5, and the reference wavelength light is outputted to the wavelength conversion semiconductor laser. 1.

[Effect]

In the basic configuration shown in FIG. 1, the wavelength conversion semiconductor laser 1 generally responds to input light of a certain wavelength λ, 1 and converts light of a wavelength λ different from λ, 7. It outputs ut light.

FIGS. 13(a) and 13(b) illustrate a wavelength conversion semiconductor laser, in which (a) shows the configuration and O)) shows its characteristics.

As shown in FIG. 13(a), the wavelength conversion semiconductor laser 1
32 is a D
It is composed of a light guide layer 134 consisting of an R8N region 1343, a phase shift region 1341 and a DBR region 1.
343 forms a wavelength control region 1344.

Since the wavelength conversion semiconductor laser 132 has a gain region and a saturable absorption region, it generally exhibits a dark value characteristic as shown in FIG. 13(b) in terms of light output characteristics.

That is, the level of input light with wavelength λ, □ is a certain value Pt
+, (λ8...), the optical output increases rapidly, and the wavelength of the output light is different from λ,7. □
It is.

Returning to FIG. 1, the signal light input section 2 inputs a group of signal lights multiplexed on the wavelength axis to the wavelength conversion semiconductor laser 1. The control unit 3 controls the wavelength conversion semiconductor laser 1
The output wavelength of the wavelength conversion semiconductor laser 1 is set according to the driving conditions.

The reference wavelength light generating section 4 generates light having a stable reference wavelength with sufficiently small wavelength fluctuation, and the reference wavelength is as follows.
Among the wavelength multiplexed optical signals input from the signal light input section 2 to the wavelength conversion semiconductor laser 1, the wavelength of the light to be selectively transmitted is selected.

The reference wavelength light input section 5 inputs the reference wavelength light outputted from the reference wavelength light generation section 4 to the wavelength conversion semiconductor laser 1 . The signal light output unit 6 outputs signal light that is selectively transmitted through the wavelength conversion semiconductor laser 1 .

As shown in FIG. 1, in the wavelength conversion semiconductor laser l,
A wavelength multiplexed signal light having wavelengths C° to λ is inputted from the signal light input section 2, and light of a certain wavelength λ, " among them is selectively transmitted, and the wavelength is stabilized with small fluctuation. It is assumed that the output is synchronized with the wavelength λ.

At this time, the control unit 3 sets the driving conditions of the wavelength conversion semiconductor laser 1 such that its oscillation wavelength is sufficiently close to the wavelength λ. Under this condition, the input light level necessary for the wavelength conversion semiconductor laser I to oscillate, that is, the input light level required for oscillation, has a dependency on the input light wavelength and reaches a minimum at a certain specific wavelength.

FIG. 14 illustrates the operating sensitivity of a wavelength conversion semiconductor laser, and shows that many maximums and minimums occur periodically.

This is due to the reflection of light between one end facet of the wavelength conversion semiconductor laser 1 and the diffraction grating, which has an effect similar to the existence of a resonator structure, and the internal gain for input light reaches its resonance peak. This is because they have a maximum at matching wavelengths.

Now, by adjusting the driving conditions of the wavelength conversion semiconductor laser 1 in the control section 3, the desired wavelength λ,'' to be transmitted can be made to match the wavelength at which the required input light level for oscillation is minimum.

FIG. 15 shows the operating conditions of the wavelength conversion semiconductor laser and the setting of the input light level.

In this state, the wavelength λ is input from the reference wavelength light input section 5.

When a reference wavelength light having a wavelength of The required input light level becomes even smaller, and when light having a wavelength near this wavelength is input, the operating sensitivity of the wavelength conversion semiconductor laser 1 increases only for that light.

The wavelength conversion semiconductor laser 1 in such a state has the above-mentioned wavelengths λ, ° to λ. input a wavelength-multiplexed signal light having a wavelength of If the value is set to a value that does not exceed the required oscillation level corresponding to that wavelength, the wavelength conversion semiconductor laser I will operate at a wavelength very close to the wavelength at which the required oscillation input light level takes the minimum value, that is, the wavelength λ, ° It only responds to light.

As a result, an optical signal with a wavelength of λ,° is converted into light with an oscillation wavelength of the wavelength conversion semiconductor laser 1, and is output. At this time, the oscillation wavelength of the wavelength conversion semiconductor laser 1 is set to the reference wavelength λ due to the injection locking operation accompanying the input of light with the reference wavelength λ.

will be synchronized.

Therefore, it is a wavelength selection filter that selectively transmits light of a desired wavelength from wavelength-multiplexed light, and the wavelength of the selectively transmitted optical signal is a stable wavelength that is synchronized with the wavelength of the reference wavelength light from the outside. A wavelength-synchronized optical wavelength selective filter having the following will be realized.

In FIG. 1, the reference wavelength light generating section 4 that generates light with a reference wavelength λ8 can be constructed using a reference wavelength light source with a stable oscillation frequency, such as a solid-state laser.

In the principle configuration shown in FIG. 2, the reference wavelength group λ
1~λ. A fixed optical wavelength selection filter 8 that selectively transmits only light having a specific wavelength λ is connected to the output of the reference wavelength light group. Since the output is inputted to the wavelength conversion semiconductor laser 1 via the reference wavelength light input section 5, wavelength multiplexed light can be processed all at once.

In the principle configuration shown in FIG. 3, a variable wavelength selection filter 9 that can variably select the wavelength that can be transmitted is connected to the reference wavelength light group generator 7, and the wavelength conversion semiconductor laser 1
Since the input reference wavelength light and the selectively transmitted light wavelength can be changed, the wavelength selectively transmitted in the wavelength conversion semiconductor laser 1 can be provided with a variable function.

In the principle configuration shown in FIG. 4, each wavelength λ1~
By combining the wavelength stabilized light sources 101 to 10-n stabilized at λ□ and the optical combiner 11 to configure the reference wavelength light group generation unit 7, the wavelength stabilized light a1o-1 to
Since the reference wavelength lights outputted from each of the reference wavelength lights 10-n are combined by the optical combiner 11 and outputted as a reference wavelength light group, the configuration is simplified.

In the principle configuration shown in FIGS. 5(a) to 5(d), as shown in FIG. 5(a), a swept signal source 12, a swept wavelength variable light source 13, and an optical interferometer By configuring the reference wavelength light group generator 7, in response to the sweep signal from the sweep signal source 12, the sweep type variable wavelength light source 13 continuously generates wavelengths λ to λ7, as shown in FIG. 5(b). and sweep it to output an optical signal. By inputting this optical output to the optical interferometer 14, only the light having a wavelength matching the interference peak wavelength of the optical interferometer 14 is outputted with strong intensity as shown in FIG. 5(C). , the interference peak wavelength of the optical interferometer 14 is set to the reference wavelength λ1 . of the wavelength multiplexed light. λ2・
, λ7, the output light can be used as a reference wavelength light group, and the configuration is further simplified.

In this case, as shown in FIG. 5(d), the reference wavelength light group includes reference wavelengths λλ2, . ...
,λ. are each independently output in the form of a pulse.

In the principle configuration shown in FIGS. 6(a) to 6(C), the configuration of the optical interferometer 14 is shown. The optical interferometer 14 may be a Fapley-Perot type interferometer as shown in FIG. 6(a), or a Matsuha-Zehnder interferometer as shown in FIG. 6(b).
Either a type interferometer or a ring type interferometer as shown in FIG. 6(C) can be used alternatively.

In the principle configuration shown in FIGS. 7(a) to (C), when the reference wavelength light group generator 7 is configured as shown in FIG. 5, the fixed wavelength selection filter 8 or the variable wavelength Instead of using the selection filter 9, the seventh [
As shown in D(a), an optical switch or optical gate 16 equipped with a drive circuit 15 is used to selectively output only a specific reference wavelength light having a desired reference wavelength,
It constitutes a reference wavelength light generating section 4. Therefore, Fig. 7(b)
), the reference wavelengths λ1 .
λ2..., λ. It is possible to select a reference wavelength light having a specific reference wavelength λ□ as shown in FIG. 7(C) from a reference wavelength light group in which each of the reference wavelength lights is independently outputted in a pulse form.

In the principle configuration shown in FIGS. 8(a) to 8(d), as shown in FIG. Figure 8 (
+) The light having continuous wavelengths as shown in l is input to the interference type optical wavelength selection filter I7, and the light having continuous wavelengths as shown in Fig. 8(C) is input.
As shown in FIG. 8(d), by transmitting light with a wavelength that matches the transmission peak wavelength and setting the transmitted wavelength as the reference wavelength λ, the reference wavelength light is Since the reference wavelength light generating section 4 is configured to output the reference wavelength light, the configuration is simplified.

In this case, the interference type optical wavelength selection filter 17 includes a Fapley-Perot type interferometer as shown in FIG. 6(a), a Matsuha-Zehnder type interferometer as shown in FIG.
It is constructed by selectively using either a ring type interferometer or a ring type interferometer as shown in FIG. 6(C).

In the principle configuration shown in FIGS. 9(a) to 9(C), the configuration is shown when reference wavelength light and signal light are input to the wavelength conversion semiconductor laser 1. In FIG. 9(a), an optical coupler 18 is used to obtain reference wavelength light λ.

A configuration is shown in which the signal lights λ1° to λ7° are combined and input to the wavelength conversion semiconductor laser 1. Figure 9(b)
, a polarizing beam splitter 19 is used to combine the signal light λ1 '' to λ7 '' and the reference wavelength light λ as light having mutually orthogonal polarization, and input the signal light to the wavelength conversion semiconductor laser 1. This shows the configuration.

In FIG. 9(C), only the reference wavelength light λ is inputted from one end face of the wavelength conversion semiconductor laser 1, and a polarizing beam splitter 19 is provided on the other end face, and the signal light λ1°
~λ0'' is polarized by the polarizing beam splitter 19 with polarization orthogonal to the polarization of the oscillation output light of the wavelength conversion semiconductor laser 1.
is input to the wavelength conversion semiconductor laser 1 via
A configuration is shown in which the oscillation output light from the wavelength conversion semiconductor laser 1 is output as polarized light perpendicular to the signal light and outputted via the polarization beam splitter 19.

When inputting the reference wavelength light and the signal light to the wavelength conversion semiconductor laser 1, one of them may be used alternatively.

〔Example〕

10, 11, 12A, and 12B each show the configuration of an embodiment of the present invention, in which light of a desired wavelength is selected from a plurality of wavelength-multiplexed optical signals. of,
A wavelength-synchronized arbitrary multi-wavelength selection filter that selectively transmits a desired number of wavelengths is shown.

In the embodiment shown in FIG. 10, 11 to 1-
n is a wavelength conversion semiconductor laser, 2-1 to 2-n are signal light input parts, 5-1 to 5-n are reference wavelength light input parts, 6-1 to 6
-n is a signal light output section.

Reference numeral 7 denotes a reference wavelength light group generation section, which together with a fixed wavelength selection filter 8 constitutes the reference wavelength light generation section 4 . In this embodiment, the fixed wavelength selection filter 8 includes an lXn optical star coupler 101 and wavelength selection filters 102-1 to 102-1.
102-n in combination. -Wavelength selection filters 102-1 to 1
02n selectively transmits light of one predetermined wavelength from the reference wavelength light group output from the reference wavelength light group generator 7, and is constructed by using a dielectric multilayer filter. Ru.

103 is an IXn optical star coupler with wavelength λ1''
The optical signal multiplexed into ~λゎ'' is distributed to n paths and inputted to the signal light input units 2-1 to 2-n connected to the wavelength conversion semiconductor lasers 1-1 to 1n. is nXl
Optical star coupler, signal light output parts 6-1 to 6-n
It combines the output lights from the two and outputs them to another optical transmission line.

As for the overall operation of this embodiment, the reference wavelength light group generator 7
Each wavelength is separated from the reference wavelength light group outputted by wavelength selection filters 102-1 to 102-n, and
By inputting the optical signal distributed from the n optical star coupler 103 to the wavelength conversion semiconductor lasers 1-1 to I-n, a desired wavelength is extracted from the optical signal distributed from the lXn optical star coupler 103. selectively transmits only the optical signal that has the

At this time, by setting the oscillation conditions of the wavelength conversion semiconductor lasers 1-1 to 1-n to be equal to the wavelength of the input reference wavelength light, the optical signal having this optical wavelength is selectively transmitted. , it is possible to output the light wavelength as a stable wavelength having the same degree of fluctuation as the reference wavelength light.

In the embodiment shown in FIG. 11, the reference wavelength light in the embodiment of FIG.
lXn optical star coupler 10 for input to ~1-n
1 and - instead of the fixed wavelength selection filter 8 configured by combining any one of the wavelength selection filters 102-1 to 102-n, reference wavelength light groups having wavelengths λ and ~λ7 are respectively used. A demultiplexer 105 is used which separates the light into n optical paths according to the wavelength of the light. The light of each wavelength separated in this way is configured to be transmitted through the wavelength conversion semiconductor lasers 1-1 to 1-n,
There is an advantage that the configuration is simplified compared to the embodiment shown in FIG. 10.

In the embodiment shown in FIG. 12A, using the lXn optical star coupler 103 in the embodiment shown in FIG. Instead of inputting the light into the wavelength conversion semiconductor lasers 1-1 to 1-n, a demultiplexer 106 is used that separates the light into n optical paths according to each wavelength, so that the light is input to the wavelength conversion semiconductor lasers 1-1 to 1-n. The configuration is such that the input signal is input to wavelength conversion semiconductor lasers i-t to 1-n.

Furthermore, in the embodiment shown in FIG. 12B, each path on the output side of the lXn optical star coupler 103 is provided with a
By inserting the wavelength converting semiconductor lasers 1-1 to 107-n, only one specific wavelength of light fluctuating in the vicinity of the desired wavelength is selected and input to the wavelength conversion semiconductor lasers 1-1 to 1-n. There is.

With the configuration shown in FIGS. 12A and 12B, the wavelength conversion semiconductor lasers 1-1 to 1-n can compensate for wavelength fluctuations for one input wavelength and achieve stable synchronization with the reference wavelength light. output as light with a certain wavelength,
Its main function is to eliminate wavelength fluctuations, and in combination with the immediately preceding single wavelength selection filters 107-1 to 107-n, a wavelength-synchronized wavelength selection filter can be realized.

[Effects of the Invention] As explained above, according to the present invention, for light of a specific wavelength among a large number of optical signals having mutually different wavelengths that are multiplexed on the wavelength axis, the light of that wavelength is When selectively transmitting light to the next stage transmission system, the wavelength-synchronized wavelength selective filter of the present invention compensates for fluctuations in the wavelength by synchronizing with light having a reference wavelength. It is possible to output an optical signal having a stable wavelength with little fluctuation. Therefore, according to the present invention, it is possible to realize a wavelength-synchronized optical wavelength-selective filter that outputs the wavelength of light as a result of the wavelength-selective transmission operation at a stable wavelength without fluctuation, thereby increasing the multiplicity of wavelengths. This greatly contributed to the realization of optical wavelength division multiplexing transmission networks.

[Brief explanation of drawings]

Figures 1 to 4, Figures 5 (a) to (d), Figure 6 (
a) - (c) Fig. 7 (a) - (C), Fig. 8 (a)
~(dll), Figures 9(a) to (C) are diagrams showing the basic configuration of the present invention, and Figure 10. Figures 11, 12A, and 12B are diagrams showing one embodiment of the present invention, respectively. 13(a) and 13(b) are diagrams illustrating the wavelength conversion semiconductor laser, FIG. 14 is a diagram illustrating the operating sensitivity of the wavelength conversion semiconductor laser, and FIG. 15 is a diagram illustrating the wavelength conversion semiconductor laser. Diagrams showing operating conditions and input light level settings, Figures 16(a) and 16(b) are for phase control type D.
FIG. 17 (aL) is a diagram showing a phase shift control type DFB semiconductor laser. 1 is a wavelength conversion semiconductor laser, 2 is a signal light input section, 3 is a control section, 4 is a diagram showing an FB semiconductor laser. 5 is a reference wavelength light generation section, 5 is a reference wavelength light input section,
6 is a signal light output section, 7 is a reference wavelength light group generation section, 8 is a fixed optical wavelength selection filter, 9 is a variable optical wavelength selection filter, 1
0-1 to 10-n are wavelength stabilized light sources, 11 is a light combiner,
12 is a swept signal source, 13 is a swept wavelength tunable light source, 14 is an optical interferometer, 15 is a drive circuit, 16 is an optical switch or optical gate, 17 is an interference type optical wavelength selection filter, 18 is an optical coupler, and 19 is a polarization light source. It is a beam splitter.

Claims (8)

[Claims] (1) Wavelength conversion semiconductor laser (
1), a control unit (3) that controls the oscillation wavelength of the wavelength conversion semiconductor laser (1), and a reference wavelength light generation unit (4) that generates reference wavelength light of a stable wavelength with little wavelength fluctuation. A wavelength-multiplexed optical signal consisting of a plurality of wavelength-multiplexed optical signals each having a different wavelength is input from the signal light input section (2) to the wavelength conversion semiconductor laser (1), and from the reference wavelength light generation section (4). A reference wavelength light having a specific wavelength in the wavelength multiplexed optical signal is sent from the reference wavelength light input section (5) to the wavelength conversion semiconductor laser (1).
), and the control section (3) sets the oscillation wavelength of the wavelength conversion semiconductor laser (1) to the same wavelength as the reference wavelength light, so that the wavelength conversion semiconductor laser (1) can perform the wavelength multiplexing. Selectively responds to an optical signal of a specific wavelength in the optical signal, converts the optical signal into light of a stable wavelength with small wavelength fluctuation synchronized with the reference wavelength light, and outputs the signal from the signal light output section (6). A wavelength-synchronized optical wavelength selection filter characterized by output. (2) The reference wavelength light generating section (4) outputs a reference wavelength light group consisting of a plurality of lights of stable wavelengths with small wavelength fluctuations of different wavelengths including one specific wavelength in the wavelength multiplexed optical signal. Claim 1, characterized in that it consists of a reference wavelength light group generating section (7) and an optical wavelength selection filter (8, 9) that selects and passes one wavelength of light from the reference wavelength light group. The wavelength-synchronized optical wavelength selective filter described above. (3) The reference wavelength light group generator (7) is connected to a sweep signal source (12) that generates a sweep signal, and the wavelength changes continuously over time by sweeping on the wavelength axis according to the sweep signal. a swept wavelength tunable light source (13) that generates an optical signal; and a swept wavelength tunable light source (13) that discretely generates, from the light generated by the swept wavelength tunable light source (13), only light having a wavelength that matches the transmission peak wavelength of the light. 3. The wavelength-synchronized optical wavelength selective filter according to claim 2, characterized in that the transmission peak wavelength of the optical interference device (14) forms a desired reference wavelength group. (4) As the optical wavelength selection filter, a fixed optical wavelength selection filter (8) or a variable optical wavelength selection filter (9) is connected to a drive circuit (15) that generates a drive signal, and selects the fixed optical wavelength based on the drive signal. Claim 1, comprising an optical switch or an optical gate (16) that separates only an optical signal of a desired wavelength from the output light of the filter (8) or the variable optical wavelength selection filter (9) on the time axis. The wavelength-synchronized optical wavelength selection filter according to item 5. (5) The reference wavelength light generator (4) is connected to a sweep signal source (12) that generates a sweep signal, and the wavelength changes continuously over time by sweeping on the wavelength axis according to the sweep signal. A swept wavelength tunable light source (13) that generates an optical signal, and from the light generated by the swept wavelength tunable light source (13), only light having a wavelength that matches the transmission peak wavelength of the light is discretely generated on the time axis. The wavelength-synchronized light according to claim 1, characterized in that the wavelength-synchronized light comprises an interference-type optical wavelength selection filter (17), and a transmission peak wavelength of the interference-type optical wavelength selection filter (17) forms a desired reference wavelength. Wavelength selective filter. (6) The signal light input from the signal light input section (2) and the signal light generated at the reference wavelength light generation section (4) and the reference wavelength light input section (
An optical coupler (1) that combines the reference wavelength light input from 5).
8), and directs the combined light to the wavelength conversion semiconductor laser (1).
) Claims 1 to 5 characterized in that
3. The wavelength-synchronized optical wavelength selective filter according to any one of the items. (7) A polarizing beam splitter (19) is provided, one input terminal of the polarizing beam splitter (19) is used as a signal light input section (2) to input the signal light as TM polarized light to the wavelength conversion semiconductor laser (1), Claim 1, wherein the other input terminal of the polarizing beam splitter (19) is used as a reference wavelength light input section (5) to input the reference wavelength light as TE polarization to the wavelength conversion semiconductor laser (1). The wavelength-synchronized optical wavelength selection filter according to any one of items 1 to 5. (8) A polarizing beam splitter (19) is provided, and one terminal of the polarizing beam splitter (19) is connected to the signal light input section (
2), the signal light is input and the output light from the other terminal is input as TM polarized light to one end face of the wavelength conversion semiconductor laser (1), and the oscillation output light of the wavelength conversion semiconductor laser (1) is input to the same end face. TE polarized light is input to the other terminal of the polarizing beam splitter (19), and the opposite terminal of the polarizing beam splitter (19) is output as a signal light output section (6). Any one of claims 1 to 5, characterized in that the other end face of the laser (1) is used as a reference wavelength light input section (5) to input the reference wavelength light into the wavelength conversion semiconductor laser (1). The wavelength-synchronized optical wavelength selective filter described in crab.