JPH09186389A - Optical control laser switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the high rate optical switching characteristics having memory function by setting the gain of a first optical resonator for vertical polarization higher than that for horizontal polarization and setting the gain of a second optical resonator for horizontal polarization higher than that for vertical polarization. SOLUTION: First and second gain waveguides W4, W1 form a first resonator while first and third gain waveguides W4, W2 form a second resonator. The gain of first optical resonator for vertical polarization is set higher than that for horizontal polarization. Furthermore, the gain of second optical resonator for horizontal polarization is set higher than that for vertical polarization. This arrangement enhances the high rate optical switching characteristics having memory function by eliminating stringent dependence on wavelength, leakage of light to the leaving signal side, returning of light to the incident signal side, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed optical signal switch used in optical information processing and optical switching systems, and an optical control laser switch having a logical operation function.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram of a bistable laser which is a conventional light control laser switch.

In FIG. 9, 8-1 is a substrate made of n-InP, 8-2 is a laser gain waveguide made of an active layer of MQW structure, 8-3 is a guide layer made of p-InGaAsP, 8-- 4 is a clad layer made of p-InP, 8
-5 is an ohmic contact layer made of p ⁺ -InGaAsP, 8-6 is a laser light gain region having a length of 300 μm, 8-7 is a saturable absorption region which is an oscillation control region having a length of 100 μm, and 8-9 is acceptable. A control electrode for applying a voltage for controlling the saturation absorption region 8-7, a current injection electrode 8-8 for supplying carriers to the gain region 8-6 of the active layer,
Reference numeral 8-10 is an electrode separation region for electrically separating the control electrode 8-9 and the current injection electrode 8-8, and 8-11 is an n-electrode made of Au or the like formed on the back surface of the substrate 8-1. . Reference numerals 8-12 and 8-13 denote reflecting mirrors arranged on both end faces of a laminated body including the substrate 8-1, the laser gain waveguide 8-2, the guide layer 8-3, and the cladding layer 8-4. , A cleavage plane, and covers the light incident end and the emission end of the laser gain waveguide. These substrate 8-1, laser gain waveguide 8-2,
Guide layer 8-3, clad layer 8-4, reflecting mirror 8-12,
The reflection mirror 8-13 constitutes a laser resonator.

The bistable laser has a structure in which the optical loss of the saturable absorption region 8-7 arranged in the resonator is controlled by the control light incident through the reflecting mirror 8-12. Electrically, by controlling the loss of the saturable absorption region 8-7, FIG.
As shown in FIG. 2A, when the injection current-light output characteristic having hysteresis as shown in FIG. 2A is realized, the electric bias condition is set at the position of the arrow A, and the control light is incident from the outer region through the reflecting mirror 8-12. As shown in b), the oscillation and non-oscillation of the laser can be steeply controlled. Since the laser once oscillated can maintain its state until a stop signal is given from the outside area, it is expected to be used for optical digital operation such as optical digital reproduction, bit memory, and flip-flop.

However, the bistable laser has the following problems because the control light is incident coaxially from the outer region into the laser resonator where the light is repeatedly returned.

That is, (a) depending on whether or not the control light has a wavelength resonating with the resonator, the control light is easily incident or almost reflected. There is such a sharp wavelength dependency. (B) The incident light leaks to the emission side, and the noise of the emission signal increases. (C) Reflected light returns to the light source on the incident side and causes noise. The above-mentioned bistable laser has such a problem that it has not been practically used.

On the other hand, focusing attention on the signal response speed of the bistable laser, the signal response speed oscillates because laser oscillation and non-oscillation with a large amount of injected carrier fluctuations are used for switching. It is rate-controlled by the relaxation oscillation wavelength in the low current injection state near the threshold value. Therefore, the bistable laser has not achieved high-speed switching exceeding 5 GHz.

As one means for solving this problem, Kawaguchi et al. Used a surface emitting laser or the like to switch two polarization directions orthogonal to each other in laser oscillation, thereby performing a high-speed optical flip-flop operation in a high current injection region. Realized (Electronic Letters, 1989)
2, 28, pp. 1645-1646). However, even with such a laser switch, as a method of switching the polarization,
Since the method of controlling the stimulated emission by coaxially injecting a signal light having a desired polarization from the outer region, the problems (a), (b), and
(C) will be taken over as it is.

[0009]

In the laser resonator in which the optical feedback is repeated, while the advantage that the high-speed optical switching operation can be realized in the high current injection region by switching the two orthogonal polarization directions of the laser oscillation is achieved. Since the control light is incident coaxially from the outer region, there is a sharp wavelength dependency that (a) the control light is easily incident or almost reflected depending on whether or not the wavelength resonates with the resonator.
An optical control laser switch that solves the conventional problems that (b) the incident light leaks to the emission side and the noise of the emission signal increases, and (c) the reflected light returns to the light source on the incidence side to cause noise. The challenge is to provide.

[0010]

In order to solve the above-mentioned problems, the light-controlled laser switch according to claim 1 of the present invention comprises
And a second gain waveguide optically connected to the first gain waveguide and having a first saturable absorption region, and optically connected to the first gain waveguide. And a third gain waveguide having a second saturable absorption region, the first gain waveguide and the second gain waveguide forming a first optical resonator, and the first gain waveguide. And the third gain waveguide form a second optical resonator, and the gain of the first optical resonator for vertically polarized light is
The gain of the first optical resonator with respect to horizontal polarization is higher, and the gain of the second optical resonator with respect to horizontal polarization is higher than the gain of the second optical resonator with respect to vertical polarization. Is characterized by.

Further, a light-controlled laser switch according to a second aspect of the present invention is the light-controlled laser switch according to the first aspect, wherein the first saturable absorption region and the second saturable absorption region are optically coupled. It is characterized by having a gain waveguide for inputting a control light which is optically coupled.

Further, according to a third aspect of the present invention, there is provided an optically controlled laser switch which comprises a first gain waveguide and a first saturable absorption region which is optically connected to the first gain waveguide. A second gain waveguide and a third gain waveguide that is optically connected to the first gain waveguide and has a second saturable absorption region. The first gain waveguide and the first gain waveguide The second gain waveguide forms a first optical resonator, and the first gain waveguide and the third gain waveguide form a second optical resonator, and the first optical resonator. Of the gain for light having a first wavelength of
Higher than the gain for light having a wavelength of
The gain of the optical resonator for the light having the second wavelength is higher than the gain of the second optical resonator for the light having the first wavelength.

That is, in the optically controlled laser switch of the present invention, the bistable laser resonator oscillating in the vertical polarization mode and the bistable laser resonator oscillating in the horizontal polarization mode each having a saturable absorption region are gain waveguides. Coupling in the middle and oscillating either one causes the other to stop oscillating. By controlling only the saturable region by external light, the problem of coaxial incidence of control light can be avoided, and a polarization switch type bistable operation capable of high-speed response can be obtained.

According to the present invention, two orthogonal laser resonators share one region of the gain region. Therefore, when the oscillation of one increases, the consumption of carriers decreases the optical gain of the other and the oscillation stops. To do. In the saturable absorption region, the loss of the resonator can be reduced only by injecting external light into a small control region, and laser oscillation can be rapidly increased. When controlling either oscillation by photoexcitation to the saturable absorption region,
It is not necessary to enter the laser gain waveguide coaxially with the polarization direction switched, and for example, the control light can be entered from a direction different from that of the laser gain waveguide such as a lateral injection waveguide or a plane vertical incidence. it can. Further, a convenient configuration in which two saturable absorption regions are controlled by one lateral injection waveguide is possible. Further, since the regions for controlling the two modes are independent, the same effect can be expected not only by switching the polarization direction but also by switching the oscillation wavelength.

[0015]

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

(First Embodiment) FIG. 1 is a configuration diagram showing a first embodiment of a laser switch according to the present invention. In the figure, W1 is a laser gain waveguide (second gain waveguide) whose waveguide width is designed to have a high gain in vertical polarization, and W2 is a laser gain waveguide designed to have a high gain in horizontal polarization. It is a waveguide (third gain waveguide), and similarly, the gain that differs depending on the polarization direction can also be realized by giving the polarization dependence to the reflectance of the reflecting mirrors R1 and R2 on each end face. W3 is a Y-branch waveguide that optically couples the two laser gain waveguides, and W4 is an optical gain waveguide (first gain waveguide) common to the two laser gain waveguides. , And has a waveguide gain almost equivalent to that of vertically polarized light and horizontally polarized light. Abs. 1 and Abs. Reference numerals 2 and 1 denote first and second saturable absorption regions for suppressing laser oscillation in the laser gain waveguide W1 direction and the laser gain waveguide W2 direction, respectively, and F1 and F2 denote the first and second saturable absorption regions, respectively. Abs. 1 and Abs. 2 is a fiber with a lens (control light input gain waveguide) that guides control light to 2 and E1, E2, E3, E4, E5, E6
Is a laser gain waveguide W1, a laser gain waveguide W2, Y
Branch waveguide W3, optical gain waveguide W4, supersaturation absorption region A
bs. 1 and 2 are electrodes for controlling current-voltage conditions in each of Seg. Is an electrode isolation region for electrically isolating each region, and QW1 is an MQW active layer having a sharp exciton absorption and an optical gain common to each waveguide. Saturable absorption region Abs. The electrodes E5 and E6 of Nos. 1 and 2 are comb-shaped electrodes on the saturable absorption region on the waveguide and have antireflection coatings on their surfaces in order to facilitate the incidence of light. In addition, in order to effectively utilize the incident light by folding back the incident light, 2 μ of the active layer QW1 is used.
A semiconductor multilayer light reflection layer DBR1 is formed under about m.

In the above-described structure, the vertically polarized and horizontally polarized bistable lasers include the reflection mirrors R1 and R2, the laser gain waveguides W1 and W2, the Y branch waveguide region W3, the saturable absorption region Abs. 1, Abs. 2, common optical gain waveguide W4,
It is composed of reflecting mirrors R1, R2 and electrodes E1, 2, 3, 4, 5, 6.

Next, the operation principle of the present embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 2 shows a graph of current-light output characteristics when each bistable laser is operated independently and light input-light output when the electrical conditions of arrow A are set.

According to FIG. 2A, the saturable absorption region Abs. Absorption saturation of spontaneous emission light to 1 and 2 progresses, and oscillation starts at a threshold value of 24 mA. Once oscillated, the electric field of light in the laser resonator remains high, and the saturable absorption region Abs. The optical absorption coefficients of 1 and 2 remain saturated, and the oscillation is maintained up to the injection current of 17 mA. In this way, the laser current / optical output characteristics are
When there is hysteresis including the value stable state, when control light is incident from the outer region in the injection current state of point A located in the middle of the hysteresis loop, oscillation / non-oscillation is controlled in response to the excitation light. . In this case, the output light has a steep hysteresis, an optical switch, and a memory characteristic with respect to the intensity of the incident light, as shown in FIG.

As described above, a structure is adopted in which one region of a plurality of laser gain waveguides having bistability is shared by the mutual relationship between the loss of saturable absorption and the gain of the laser gain waveguide due to current injection. Is the laser switch of the first embodiment described in FIG. Since the amount of current supplied to the supplied gain waveguide is constant, when oscillating in one laser mode, laser oscillation in different modes is deprived of the optical gain and suppressed. 2 of the laser switch when both are operated at the same time
The hysteresis characteristics of the two modes are shown in FIG. In the common optical gain waveguide W4, carriers are consumed for either one of the oscillations. Therefore, for example, the TM polarization waveguide and the saturable absorption region Abs. In the hysteresis characteristic of the current / light output that appears as the effect of 1, when the TM mode is in the oscillation (on) state, the output of the TE polarized light is off. Therefore, it is possible to obtain a bistable characteristic in which one of the two oscillates complementarily. For example, when the TM-polarized mode oscillates, the saturable absorption region that contributes to the TM-mode becomes transparent. Therefore, after that, the saturable absorption region Abs on the TE mode side, which is unoscillated, is insensitive to external light. ． In No. 2, excitons are excited by the incidence of control light from the outer region, saturable absorption loss is reduced, and the bistable laser starts oscillation in the TE mode. As a result, the TM polarization mode that has been oscillating until now loses its gain, oscillation stops, and the saturable absorption region Abs. The value 1 also increases the light absorption coefficient.

On the contrary, the saturable absorption region Ab on the TM oscillation side
s. When the oscillation starts by exciting 1, the oscillation of the TE polarized light is suppressed, and the switching is executed by the change of the oscillation mode of T ← → TM. Since the electric field of light incident in the direction perpendicular to the plane resonates with excitons caused by the heavy holes of the superlattice grown on the <100> plane, the switching sensitivity is independent of the incident polarization direction. equal. About 50% of the external light is absorbed in one direction by the active layer in the saturable absorption region with a thickness of 0.2 μm, but it is reflected by the semiconductor DBR layer in the lower region and is absorbed, so that
5% is absorbed and contributes to switching. Since the bistable switching speed is performed in a region where the carrier density is several times the normal oscillation threshold current, the switching on speed can be 10 GHz or more. Generally, in a normal bistable laser that turns on and off with two values of oscillation and non-oscillation, the switching off is rate-controlled by the recovery time of the saturable region, but in the case of the method using the competition between these two oscillation modes Since it is linked with the switching on of the orthogonal mode, the off operation is performed promptly in conjunction with the on operation of the other modes, and is sufficiently fast as the on time.

FIG. 4 shows the relationship between the control light incidence and the output light timing in each polarization direction. The light incident from the fiber F1 provides vertical and horizontal outputs from the optical gain waveguide W4, and complementarily obtains vertically polarized oscillation and non-oscillation intensity switching outputs from the laser gain waveguide W1. Horizontally polarized oscillation and non-oscillation intensity switching output is obtained from the laser gain waveguide W2. There is no leakage of the input signal in each output, and no return of the output signal on the incident light side. In this case, the coupling of the waveguides having two different mode gains is not always lateral to the crystal plane. As shown in FIG. 5, there are two waveguides TM1 and TE1 overlapping in the thickness direction of the crystal plane, and the same effect as above can be expected via the common gain waveguide G1 and directional coupling waveguide C1. In this case, since the laser gain of each polarized light can be selected by the strain amount (tensile strain or compressive strain) of each crystal active layer, there is an advantage that the waveguide structure can be formed in the same size and the production process can be simplified.

(Second Embodiment) Next, the second embodiment of the present invention will be described.
An embodiment will be described. This embodiment is the second embodiment of the present invention.
It corresponds to the claim.

FIG. 6 is a block diagram of an optically controlled laser switch showing a second embodiment of the present invention. In the figure, W1 is a laser whose waveguide width is designed to have a high gain for vertically polarized light. A gain waveguide (second gain waveguide) W2 is a laser gain waveguide (third gain waveguide) having a high gain in horizontal polarization, and the gain is polarization-dependent on the reflectance of the reflecting mirror on each end face. Can also be achieved by giving W3 is a Y-branch waveguide that optically couples the two laser gain waveguides W1 and W2, and W4 is an optical gain waveguide (first gain waveguide common to the two laser gain waveguides W1 and W2). Waveguide)
And Abs. 1 and Abs. Reference numerals 2 and 1 denote first and second saturable absorption regions for suppressing oscillation of the laser gain waveguides W1 and W2, respectively. 1 is the saturable absorption region Ab
s. 1 and Abs. 2 is a lateral optical injection waveguide (control light input gain waveguide) for guiding control light to Also, E1, E
2, E3 and E4 are the laser gain waveguide W1, the laser gain waveguide W2, the Y branch waveguide region W3, and the optical gain waveguide W.
4, supersaturated absorption region Abs. 1 and 2 are electrodes for controlling the gain current in each of Seg. Is an isolation region for electrically isolating each region, and QW1 is an MQW active layer having steep exciton absorption and optical gain, which is common to the respective waveguides. Saturable absorption region Abs. Lateral injection waveguide Sub. In No. 1, the incident end face is provided with antireflection coating AR.

In the above structure, the vertically polarized bistable laser resonator is composed of the reflecting mirrors R1 and R3 and the laser gain waveguide W.
1, Y branch waveguide W3, saturable absorption region Abs. 1. Common optical gain waveguide W4. Further, the horizontally polarized bistable laser includes a reflecting mirror R2, a laser gain waveguide W2,
Y branch waveguide W3, saturable absorption region Abs. 2. Common optical gain waveguide W4 and reflecting mirror R3. Since the optical gain waveguide W4 and the Y branch waveguide region W3 are common to both modes, when oscillating in one mode at a constant current value, the optical gain for the other oscillation is insufficient and suppressed. This mode switching depends on the oscillation rise time (relaxation oscillation frequency) of the laser that is switched on, and high-speed mode switching is possible if the current value is set higher than the normal oscillation threshold value.

Next, the operation principle of this embodiment will be described with reference to FIG.

With the configuration of this embodiment, as in the case of the first embodiment, as shown in FIG. 3, it is possible to obtain a bistable characteristic in which either one oscillates complementarily. Optical lateral injection waveguide Sub. 1 functions as a signal light introducing waveguide having an optical amplification function by current injection. With a small incident control light of about 10 microwatts, a sufficient reaching light intensity of about 1 milliwatt can be obtained, and the saturable absorption region is effectively excited.

For example, when the laser gain waveguide W2 is oscillating in the TE polarization mode, the saturable absorption region Abs. 2 is already transparent, but the Abs. No. 1 is on the waveguide W1 to be oscillated with TM polarized light, the optical gain is suppressed,
Exciton absorption loss is high. This saturable absorption region Abs. 1 to the lateral injection waveguide Sub. When the control light from 1 arrives, the absorption loss decreases, and the bistable laser oscillates in the TM mode. In synchronization with this, the TM-polarized mode of the laser gain waveguide W2 deprived of the optical gains of the Y branch waveguide W3 and the optical gain waveguide W4, which are the common portions, stops oscillating.

On the contrary, when the TM polarization mode is transmitted from the laser gain waveguide W1 in advance, the saturable absorption region Abs. Since 1 is already transparent, the laser gain waveguide W1 is the lateral injection waveguide S
ub. It is insensitive to external light incident from 1, but
The saturable absorption region Abs. Of the non-oscillation mode of the TE polarization on the laser gain waveguide W2 located at the end of the saturable absorption region Abs. 2 is a lateral injection waveguide Sub. The bistable laser starts to oscillate because it is excited by the external light from 1 to reduce the absorption loss. As a result, the polarization mode that has been oscillating up to now loses its gain and stops oscillating, and the saturable region Abs1. Also increases absorption. The electric field of light incident from the lateral direction that is not coaxial with the laser gain waveguide is
It is absorbed from one direction by the active layer in the saturable absorption region having a width of 3 μm. Then, 75% of the external light is absorbed and contributes to switching. The bistable switching speed is performed in a state where the carrier density is several times the normal oscillation threshold current,
The switching on speed can be 10 GHz or more. The switching off is normally limited by the recovery time of the saturable region, but in this case, since it is linked to the switching on of the orthogonal mode, it is sufficiently fast as the on time.

FIG. 7 shows an example of the relationship between the control light incidence and the output light timing in each polarization direction. Lateral injection waveguide Su
b. By the light incident from the laser gain waveguide W1
From the laser gain waveguide W2, and vertically polarized oscillation and non-oscillation intensity switching are obtained from the laser gain waveguide W2, and horizontally polarized oscillation and non-oscillation from the optical gain waveguide W4. The intensity switching output of is obtained. There is no leakage of the input signal in each output, and no return of the output signal on the incident light side. In addition, each saturable absorption region Abs. 1, Abs. The incident light amplification roads may be independently provided so that the control lights can enter the two separately.

Also in this case, the coupling of the waveguides having two different mode gains is not limited to the lateral direction with respect to the crystal plane, as in the first embodiment. As shown in FIG. 5, there are two waveguides TM1 and TE1 overlapping in the thickness direction of the crystal plane, and the same effect as above can be expected via the common gain waveguide G1 and directional coupling waveguide C1. In this case, since the laser gain of each polarized light can be selected by the strain amount (tensile strain or compressive strain) of each crystal layer, the waveguide structure can be formed in the same size, and the structure can be simplified. Also,
The control light can enter from the direction perpendicular to the surface.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
An embodiment will be described. This embodiment corresponds to claim 3 of the present invention.

FIG. 8 is a block diagram of the third embodiment of the light control laser switch according to the present invention. In the figure, W1 is a laser gain waveguide (second gain waveguide) having a distributed feedback grating designed to have a high gain at wavelength λ1, and W2 is designed to have a high gain of λ2 for horizontally polarized light. Is a laser gain waveguide (third gain waveguide) having a distributed feedback grating, and W3 is a Y-branch waveguide that optically couples the two waveguides. Also, W
Reference numeral 4 denotes an optical gain waveguide (first gain waveguide) common to the two laser gain waveguides, and the optical gain waveguide W4 is not provided with a wavelength selective grating.
Also, Abs. 1 and Abs. Reference numerals 2 and 1 denote first and second saturable absorption regions for suppressing oscillation of the laser gain waveguides W1 and W2, respectively. 1 is the saturable absorption region Abs.
1 and Abs. 2 is a lateral optical injection waveguide (control light input gain waveguide) for guiding control light to E1, E2, E3, E4
Is a laser gain waveguide W1, a laser gain waveguide W2, Y
Branch waveguide W3, optical gain waveguide W4, supersaturation absorption region A
bs. 1 and 2 are electrodes for controlling the gain current in each of Seg. Is an isolation region for electrically isolating each region, and QW1 is an MQW active layer common to the respective waveguides having steep exciton absorption and optical gain. Saturable absorption region Abs. Lateral injection waveguide Sub. In No. 1, the incident end face is provided with antireflection coating AR.

In the above-mentioned structure, the vertically polarized bistable laser resonator includes the reflector R3, the grating on the laser gain waveguide W1, the laser gain waveguide W1, and the Y branch waveguide W.
3, saturable absorption region Abs. 1. Common optical gain waveguide W4
It consists of. Further, the horizontally polarized bistable laser includes a reflector R3, a grating on the laser gain waveguide W2, a laser gain waveguide W2, a Y branch waveguide W3, a saturable absorption region Abs. 2. Common optical gain waveguide W4. Since the optical gain waveguide W4 and the Y-branch waveguide W3 are gain regions common to both wavelengths, when oscillating at one wavelength at a constant current value, the optical gain for the other oscillation is insufficient,
Suppressed. This mode switching depends on the rise time (relaxation oscillation frequency) of the laser that is switched on, and if the current value is set higher than the normal oscillation threshold value,
High-speed mode switching is possible like a switch using polarized light. The procedure of the operation is the same as that of the second embodiment, so the explanation is omitted.

[0036]

As described above, according to the optically controlled laser switch of the present invention, the laser gain waveguides that are likely to oscillate with two polarizations or respective wavelengths are coupled to each other in one region and each saturable wavelength is adjusted. By exciting the absorption region with a high-speed control signal light from a direction not coaxial with the laser gain waveguide (for example, a plane vertical incidence or a lateral injection waveguide), a high-speed optical switching characteristic having a memory property can be obtained. It can be obtained after solving practical problems such as severe wavelength dependence, (b) leakage light to the output signal side, and (c) return light to the input signal side. Moreover, the output of the optically controlled laser switch of the present invention is in the direction of the waveguide, and it is possible to take out an output in a single polarization direction or only a wavelength, or a signal in both polarizations. Flip-flop operation and simultaneous output of DATA and DATA-Bar are possible, which is suitable for logical operation. Further, since it is small and can be made into a module, it can be easily used and can be used for a high-speed optical signal processing device, an optical transmission device, and the like.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a polarized light laser switch according to a first embodiment of the present invention.

2A and 2B are diagrams for explaining bistable light output suppression of a light control laser switch, FIG. 2A is a graph showing a gain current-light output characteristic, and FIG. 2B is a condition of an arrow in FIG. 5 is a graph showing optical input-optical output characteristics in FIG.

FIG. 3 is a graph showing input / output characteristics of a light control laser switch (two-polarization laser switch).

FIG. 4 is a graph showing operating characteristics of the light control laser switch according to the first embodiment of the present invention.

FIG. 5 is a sectional configuration diagram of an optically controlled laser switch (polarized light laser switch) for explaining the first embodiment of the present invention.

FIG. 6 is a configuration diagram of an optically controlled laser switch (polarized light laser switch) according to a second embodiment of the present invention.

FIG. 7 is a graph showing operating characteristics of the light control laser switch according to the second embodiment of the present invention.

FIG. 8 is a configuration diagram of an optical control laser switch (laser wavelength optical switch) according to a third embodiment of the present invention.

FIG. 9: Conventional optical control laser switch (bistable laser)
FIG.

[Explanation of symbols]

Abs. 1 First saturable absorption region Abs. 2 Second saturable absorption region F1, F2 Fiber with lens for guiding control light (control light input gain waveguide) Sub. 1 Optical lateral injection waveguide for guiding control light (control light input gain waveguide) W1 laser gain waveguide (second gain waveguide) W2 laser gain waveguide (third gain waveguide) W3 Y branch waveguide W4 optical gain waveguide (first gain waveguide)

Claims (3)

[Claims] 1. A first gain waveguide, a second gain waveguide optically connected to the first gain waveguide and having a first saturable absorption region, and the first gain waveguide. A third gain waveguide that is optically connected to the waveguide and has a second saturable absorption region, wherein the first gain waveguide and the second gain waveguide form a first optical resonator. The first gain waveguide and the third gain waveguide form a second optical resonator, and the gain of the first optical resonator with respect to vertical polarization is
Is higher than the gain of the second optical resonator with respect to horizontal polarization, and the gain of the second optical resonator with respect to horizontal polarization is
The optical control laser switch is characterized in that it is higher than the gain for the vertically polarized light of the optical resonator of. 2. The optical control according to claim 1, further comprising a gain waveguide for inputting control light, which is optically coupled to the first saturable absorption region and the second saturable absorption region. Laser switch. 3. A first gain waveguide, a second gain waveguide optically connected to the first gain waveguide and having a first saturable absorption region, and the first gain waveguide. A third gain waveguide that is optically connected to the waveguide and has a second saturable absorption region, wherein the first gain waveguide and the second gain waveguide form a first optical resonator. And the first gain waveguide and the third gain waveguide form a second optical resonator, and the gain of the first optical resonator for light having a first wavelength is The gain of the first optical resonator with respect to the light having the second wavelength is higher, and the gain of the second optical resonator with respect to the light having the second wavelength is higher than that of the second optical resonator. An optically controlled laser switch having a higher gain than that of light having a wavelength of 1.