JPH0876153A - Integrated optical deflecting element - Google Patents

Abstract

PURPOSE: To provide an integrated optical deflecting element suitable for executing optical switching, parallel optical information transmission, etc., capable of dealing with ultra-high band information transmission in the future. CONSTITUTION: A waveguide layer 5 penetrating an EA modulator part 4 and an LAD part 3 is formed on a semiconductor substrate 2. This EA modulator part 4 has first, second clad layers 6, 7 in the upper part of the waveguide layer 5 and an electrode layer 10 for driving the EA modulator formed atop these layers. The LAD part 3 has the first, second clad layers 6, 7 in the upper part of the waveguide layer 5, a secondary diffraction grating 8 formed on the first clad layer 6 and an electrode layer 9 for driving the LAD having a window part 13 to emit the light diffracted by the secondary diffraction grating 8 to an external space. A common electrode layer 11 is formed on the rear surface of the semiconductor substrate 2. The EA modulator part 4 and the LAD part 3 are held electrically insulated by a groove 12 for isolation.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is applied to the field of information processing or communication, for example, for optical switching between boards in a large computer, between processors, or optical interconnection for parallel optical information transmission. The present invention relates to a suitable integrated optical deflection element.

[0002]

2. Description of the Related Art In recent years, there have been remarkable developments in optical devices, and various optical devices have been used particularly in the fields of information processing and communication. For example, an optical waveguide element can have various functions depending on its configuration. When a diffraction grating is formed in the element, only light of a specific wavelength of light incident on the element is directed in the traveling direction of the light. To 18
It is possible to return in the opposite direction of 0 °, or to bend the light in the vertical direction and emit the light to the external space of the element. An example of this type of light deflection element is described in the document “Optics 18,82-90 (1
989) ”and“ Optics 21,442-450 (1992) ”, there is an integrated optical pickup using a condensing grating coupler. This optical integrated pickup is capable of detecting data on an optical disk by spatially entering and emitting a laser beam with respect to the optical disk.

[0003]

In the field of information processing, for example, between boards in a large computer,
When electrical wiring, which is a conventional means, is used as the wiring for transmitting information between processors and the like, the spatial and time loss occupied by the wiring becomes considerably large.
Therefore, in order to improve this point, there is a need for so-called optical interconnection (interconnection using light) that uses light having a large amount of information transmission spatially and temporally.

When an optical interconnection is constructed in a large-sized computer, in order to take advantage of the large amount of information transmission that the optical interconnection has in terms of space and time, the space between boards and processors is spatial. There is a demand for means for easily performing optical switching for switching signals and parallel optical information transmission. However, at present, there is no means for easily satisfying such a requirement, and if the conventional light deflection element is used, it can simply deflect the light and emit it to the external space of the element. It was not compatible with switching or parallel optical information transmission. Therefore, it has been desired to provide an optical device capable of coping with optical switching and parallel optical information transmission, which takes full advantage of optical interconnection.

Furthermore, in order to realize optical information transmission in the ultra-high band of 1 Tbit / cm ² · sec (10 ¹² bit / cm ² · sec) order as optical information transmission in the future, information is transmitted to light. There is a limit in adopting the direct modulation method of the optical signal as a means for superimposing. For example, when a semiconductor laser is used as a light source, direct modulation of the semiconductor laser can obtain an optical signal of the order of at most 10 Gbit / cm ² · sec (10 ¹⁰ bit / cm ² · sec). It cannot support ultra-high bandwidth optical information transmission. Therefore, it has become necessary to introduce an external modulation method capable of performing higher-speed modulation instead of the direct modulation method.

On the other hand, when an optical deflecting element is applied to optical switching and the optical deflecting element distributes a high-speed optical signal to a light receiving element such as a photodiode, if the continuously emitting signal is deflected as it is, the signal is switched. There is a concern that an error of the received light signal may occur at the boundary between adjacent light receiving elements. In other words, not only can it support optical information transmission and optical switching at the current level, but it can be applied to optical information transmission and optical switching at the time when the signal becomes ultra-high bandwidth in the future, and there will be no problems such as error occurrence. However, it has been desired to provide an optical device capable of dealing with this with high certainty.

The present invention has been made in view of the above circumstances, and in particular, it relates to an optical interconnection for performing optical switching, parallel optical information transmission, or the like, which can cope with future ultra-high bandwidth optical information transmission. It is an object of the present invention to provide a suitable integrated light deflection element.

[0008]

In order to achieve the above-mentioned object, an integrated optical deflection element according to claim 1 has an electro-absorption modulation element section for modulating incident light and an electro-absorption modulation element section. An integrated optical deflection element in which an optical deflection element section that deflects incident light and emits it to an external space is integrated on a semiconductor substrate, and the electroabsorption modulation element section and the optical deflection element are provided on the semiconductor substrate. A waveguide layer penetrating the waveguide layer is formed, and the electro-absorption modulation element portion includes a cladding layer formed on the waveguide layer, an upper electrode layer formed on an upper surface of the cladding layer, and the semiconductor substrate. A lower electrode layer formed on the lower surface of the optical deflection element section, and the optical deflection element section is formed on the cladding layer formed on the upper surface of the waveguide layer and on the upper surface of the waveguide layer or the cladding layer, And a secondary diffraction grating to diffract upwards Is formed on the top surface of the clad layer,
An upper electrode layer having a window portion for emitting the diffracted light to an external space and a lower electrode layer formed on the lower surface of the semiconductor substrate are provided, and the light deflection element portion and the electro-absorption modulation element portion are electrically connected. It is characterized by being electrically insulated.

According to another aspect of the integrated optical deflector of the present invention, there is provided a laser element section for oscillating light, an electro-absorption modulator element section for modulating light incident from the laser element section, and the electro-absorption element. An integrated optical deflection element in which an optical deflection element section that deflects light incident from a modulation element section and emits it to an external space is integrated on a semiconductor substrate, and the laser element section and the electric field are formed on the semiconductor substrate. A waveguide layer penetrating the absorption modulation element portion and the light deflection element portion is formed, and the laser element portion includes an active layer formed on the waveguide layer and a clad formed on the active layer. A layer, a first-order diffraction grating formed on the upper surface of the active layer or the clad layer, and an upper electrode layer formed on the upper surface of the clad layer,
A lower electrode layer formed on the lower surface of the semiconductor substrate,
The electro-absorption modulation element part has a clad layer formed on the waveguide layer, an upper electrode layer formed on the upper surface of the clad layer, and a lower electrode layer formed on the lower surface of the semiconductor substrate. The optical deflection element portion includes a clad layer formed on the waveguide layer, and a second-order diffraction grating formed on the upper surface of the waveguide layer or the clad layer for diffracting light upward. A laser element portion having an upper electrode layer formed on an upper surface of the cladding layer and having a window portion for emitting the diffracted light to an external space, and a lower electrode layer formed on a lower surface of the semiconductor substrate. And the electro-absorption modulation element section and the optical deflection element section are electrically insulated from each other.

The integrated optical deflector according to claim 3 is characterized in that the laser element portion is formed as a distributed feedback laser element or a distributed Bragg reflector laser element.

[0011]

In general, the relationship between the diffraction angle and the refractive index in an optical waveguide device having a second-order diffraction grating is represented by the following Bragg equation, where i = 2. That is,
Assuming that the diffraction angle is θ and the equivalent refractive index of the waveguide medium is neff, sin θ = i · {λ ₀ / (neff · Λ)}-1 (1) i: Order of diffraction grating λ ₀ : of incident light Wavelength Λ: It becomes the pitch of the diffraction grating. Here, if general conditions for the optical waveguide device are applied to each parameter, θ = 90 °. That is, the light is diffracted in the direction perpendicular to the traveling direction. Therefore, when a voltage is applied between the upper electrode layer and the lower electrode layer in the optical deflection element section of the integrated optical deflection element of the present invention, the refractive index of the waveguide layer changes due to the electro-optical effect. Alternatively, even when current is injected between the upper electrode layer and the lower electrode layer, the refractive index of the waveguide layer changes due to the plasma effect or band filling effect of the injected carriers. Therefore, if the refractive index of the waveguide layer is changed by a certain amount by adjusting the applied voltage or the injection current,
As is clear from the equation (1), the diffraction angle changes by a certain amount accordingly. That is, it becomes possible to deflect the diffracted light by an arbitrary angle within a range in which the refractive index can be changed.

Next, the electro-optical effect is further enhanced. That is, when the voltage applied to the waveguide layer is increased, the change in the refractive index is also increased, and the phenomenon that the transmission wavelength determined by the substance is largely shifted to the long wavelength side occurs. Therefore, the waveguide layer that transmits light when no voltage is applied absorbs light due to the above phenomenon when voltage is applied, and thus blocks light.

Therefore, in the integrated optical deflector according to the first aspect, light is incident on the waveguide layer of the electro-absorption modulation element section using an arbitrary light source, and at the same time as the upper electrode layer of the electro-absorption modulation element section. When a voltage is applied between the lower electrode layer,
As described above, the transmission wavelength determined by the substance is shifted to the long wavelength side and the incident light is absorbed, so that the incident light is blocked. At this time, since the shift of the transmission wavelength due to the voltage application is a very fast reaction, a voltage application power source, for example,
If a device that can apply a high-speed pulse voltage of the order of psec (10 ^-12 seconds) is used, light transmission and blocking will also be performed on the order of psec. Is possible. Then, the optical signal thus modulated is incident on the optical deflection element section through the waveguide layer, is deflected by the secondary diffraction grating, and is emitted to the external space of the element through the window section of the upper electrode layer.

Further, in the integrated optical deflection element according to the second aspect, in addition to the optical deflection element section and the electro-absorption modulation element section, a laser element section for oscillating light incident on these element sections is provided. Laser light is oscillated by the current injection into the active layer by the upper electrode layer and the lower electrode layer of the laser element portion and the action of the first-order diffraction grating, and the laser light is absorbed by the electric field through the waveguide layer that penetrates each element portion. Modulation element part,
The light is sequentially incident on the light deflection element section. Then, in the electro-absorption modulation element section and the optical deflection element section, high-speed external modulation of light is performed in the electro-absorption modulation element section, and the modulated optical signal is generated in the optical deflection element section, as in the first aspect. The light is deflected and emitted to the external space of the element through the window of the upper electrode layer.

Further, in the integrated optical deflector according to the third aspect, since the laser element portion is formed as a distributed feedback laser element or a distributed Bragg reflector laser element, a single mode laser light is generated. The single mode light that is oscillated is externally modulated at high speed by the electro-absorption modulation element section, and the modulated optical signal is deflected by the optical deflection element section and emitted to the external space of the element.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to. FIG. 1 is a view showing a cross section of an integrated optical deflector 1 according to the first embodiment, in which an optical deflector element portion 3 (Light Angular Deflector, hereinafter referred to as LAD) is formed on a semiconductor substrate 2.
Section) and the electroabsorption modulator section 4 (Electric Absorpt).
An ion modulator, hereinafter referred to as an EA modulator section) (electroabsorption modulation element section) is integrated. In the figure, reference numeral 5 is a waveguide layer, 6 is a first cladding layer, 7 is a second cladding layer,
Reference numeral 8 is a second-order diffraction grating, 9 is a LAD driving electrode layer (upper electrode layer), 10 is an EA modulator driving electrode layer (upper electrode layer),
Reference numeral 11 is a common electrode layer (lower electrode layer).

The semiconductor substrate 2 is made of p-InP as a material and is formed in a chip shape. Then, the LAD section 3 and the EA modulator section 4 are provided at the center of the upper surface of the semiconductor substrate 2 in the width direction.
A waveguide layer 5 is formed so as to extend through the substrate in the longitudinal direction of the substrate 2. The waveguide layer 5 includes an InGaAsP layer and an In layer.
The P layers are alternately laminated in a multi-layer structure, and have a so-called multi quantum well (hereinafter, referred to as MQW) structure. The composition wavelength of the waveguide layer 5 (oscillation wavelength determined by the composition of the layer) is 1.15 μm.
Is set to Then, the light S ₀ is incident from the EA modulator portion 4 side of the waveguide layer 5 toward the LAD portion 3 side.

In the LAD section 3, n- is formed on the waveguide layer 5.
A first clad layer 6 which is a thin layer made of InP is formed, and a second-order diffraction grating 8 in which a groove extending in a direction orthogonal to the traveling direction of the light S ₀ is formed on the upper surface of the first clad layer 6. Are formed. The secondary diffraction grating 8 is for diffracting the light S ₀ transmitted through the inside of the waveguide layer 5 upward. Then, the second cladding layer 7 made of n-InP is laminated so as to cover the first cladding layer 6 and the waveguide layer 5.

The composition of n-InP forming the first and second clad layers 6 and 7 has a refractive index gradually decreasing in the order of the waveguide layer 5, the first clad layer 6 and the second clad layer 7 ( The value of the composition wavelength becomes smaller). Further, the thicknesses of these clad layers 6 and 7 are set so that the first clad layer 6 is sufficiently thin as compared with the second clad layer 7, so that the second-order diffraction grating 8 is formed in the waveguide layer 5
It is located in the immediate vicinity of the second-order diffraction grating 8 so that the portion of the light S ₀ leaching outward from the waveguide layer 5 reaches the second-order diffraction grating 8.

On the other hand, in the EA modulator section 4, a second cladding layer 7 having the same composition as the second cladding layer 7 of the LAD section 3 is formed so as to cover the waveguide layer 5. An isolation groove 12 is formed between the second clad layer 7 of the LAD section 3 and the second clad layer 7 of the EA modulator section 4, and an air gap is formed between the clad layers 7 and 7. The layers are interposed so that the LAD section 3 and the EA modulator section 4 are electrically insulated from each other.

Further, an LAD driving electrode layer 9 and an EA modulator driving electrode layer 10 are formed on the upper surfaces of the second cladding layers 7 of the LAD section 3 and the EA modulator section 4, respectively.
The LAD drive electrode layer 9 has a window portion 13 for emitting the light S ₁ diffracted upward by the secondary diffraction grating 8 to the external space.
Are formed. On the other hand, LA is formed on the lower surface of the semiconductor substrate 2.
A common electrode layer 11 used as a lower electrode is formed commonly in the D section 3 and the EA modulator section 4.

Next, a procedure for manufacturing the integrated optical deflector having the above structure will be described with reference to FIGS.
First, on the semiconductor substrate 2 shown in FIG.
As shown in, the metal-organic vapor phase epitaxial device (Orga
no Metallic Vapor Phase Epitaxy, OMVPE
The waveguide layer 5 having the MQW structure is grown by using a device). Then, as shown in FIG. 2C, the first thin film
After growing the clad layer 6, the first insulating film 14 is formed and patterned to leave the first insulating film 14 only in the EA modulator section 4, and the first clad layer of the LAD section 3 is formed. The upper surface of 6 is etched to form the secondary diffraction grating 8. Then, after removing the first insulating film 14 left in the EA modulator unit 4, as shown in FIG.
The second cladding layer 7 is grown on the upper surface of the first cladding layer 6.

Then, as shown in FIG. 3E, the second insulating film 15 is formed on the upper surface of the second cladding layer 7 and then patterned to form the EA modulator portion 4 and the LAD.
The opening 16 is formed at the boundary of the portion 3. And FIG.
As shown in (f), the patterned second insulating film 15 is formed.
Is used as a mask to form the isolation groove 12 by etching up to the upper surface of the waveguide layer 5,
After removing the insulating film 15, the LAD driving electrode layer 9 and the EA modulator driving electrode layer 10 are provided on the upper surfaces of the second cladding layers 7 and 7 of the EA modulator section 4 and the LAD section 3, and the lower surface of the semiconductor substrate 2 is provided. The window portion 13 is formed by growing the common electrode layer 11 and patterning the LAD driving electrode layer 9. Through the above procedure, the integrated optical deflection element 1 of the first embodiment is completed.

Therefore, when the integrated optical deflection element 1 is used, as shown in FIG. 4, a first power source 17 is provided between the EA modulator driving electrode layer 10 and the common electrode layer 11, as shown in FIG. Further, the second power source 18 is connected between the LAD driving electrode layer 9 and the common electrode layer 11. Then, light S ₀ is incident from the end of the waveguide layer 5 on the EA modulator section 4 side by an arbitrary light source, and the first power supply 17 causes the p-type semiconductor substrate and the n-type cladding layer in the EA modulator section 4. In contrast, a positive pulse voltage of about 10 V is applied to the EA modulator driving electrode layer 10 side and a negative pulse voltage of about 10 V is applied to the common electrode layer 11 side so that a reverse bias is applied to the EA modulator driving electrode layer 10 side. Waveguide layer 5
A voltage of about 3 to 4 V is applied to. Then EA
The modulator unit 4 blocks the incident light S _{0 according} to the pulse voltage,
The transmission is repeated, that is, the modulation is performed, and then L
The AD unit 3 diffracts the light S ₁ at a diffraction angle according to the applied voltage and emits the light S ₁ to the external space of the element 1.

In the integrated optical deflector 1 of this embodiment, the maximum refractive index change amount of the waveguide layer 5 when a voltage is applied between the LAD driving electrode layer 9 and the common electrode layer 11 in the LAD section 3. Is about 1%. Therefore, when calculation is performed using the above expression (1) from this refractive index change amount, it becomes possible to deflect light by approximately 12.5 ° with respect to θ = 90 ° when no voltage is applied. Therefore, the light can be deflected in the range of 0 to 10 ° by appropriately adjusting the magnitude of the voltage. Even if the amount of change in the refractive index is estimated to be about 0.5%, it is possible to perform the deflection of 8 °.

In particular, in this embodiment, since the EA modulator section 4 for modulating the incident light S ₀ is provided in the preceding stage of the LAD section 3, the waveguide layer 5 is supplied from the first power supply 17 to the waveguide layer 5. Light is absorbed in a pulsed manner by applying an arbitrary pulse voltage, and high-speed external modulation can be performed by repeatedly blocking and transmitting light at high speed. Therefore, the high-speed externally modulated light enters the LAD unit 3, is diffracted, and is emitted to the external space of the element, so that various effects can be obtained when applied to optical interconnection. The specific effect when applied to optical interconnection will be described later.

Further, since the integrated optical deflection element 1 of this embodiment adopts the MQW structure for the waveguide layer 5, the temperature characteristic of the refractive index can be improved and the isolation groove 12 of the isolation groove 12 can be improved. Since the depth is set to the upper surface of the waveguide layer 5, there is no break in the waveguide layer 5, and the waveguide layer 5 with less loss can be obtained. Furthermore, since the structure is such that the second-order diffraction grating 8 is formed on the upper surface of the first clad layer 6, the distance from the waveguide layer 5 to the second-order diffraction grating 8 is appropriately adjusted by controlling the thickness of the first clad layer 6. Therefore, it is possible to form the secondary diffraction grating 8 with high efficiency and improve the intensity of the emitted light S ₁ .

Next, the second type of the integrated optical deflector of the present invention will be described.
An embodiment will be described with reference to FIGS. FIG. 5 is a diagram showing a cross section of the integrated optical deflector 19 of the second embodiment, in which the same LAD as that of the first embodiment is formed on the semiconductor substrate 2.
In addition to the formation of the section 3 and the EA modulator section 4, a distributed feedback laser element section 20 (Distributed FeedBack, hereinafter referred to as a DFB laser section) (laser element section) is integrated. The LAD unit 3 and the EA modulator unit 4
The configuration is substantially the same as that of the first embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and detailed description of the LAD unit 3 and the EA modulator unit 4 will be omitted.

The DFB laser section 20, the LAD section 3, and the EA are formed in the widthwise central portion of the upper surface of the semiconductor substrate 2 made of p-InP.
A waveguide layer 5 is formed which penetrates the modulator portion 4 and extends in the longitudinal direction of the substrate 2. Similar to the first embodiment, this waveguide layer 5 has an MQW structure and has a composition wavelength of 1.15 μm. The difference between the second embodiment and the first embodiment is that the element 19 itself has a light source inside. Therefore, the laser light oscillated by the DFB laser unit 20 passes through the waveguide layer 5 and the EA modulator unit 4 and the LAD unit 3
Are sequentially incident.

In the DFB laser section 20, the first cladding layer 6 which is a thin layer of n-InP is formed on the waveguide layer 5.
Is formed, and the active layer 21 is formed on the first cladding layer 6. This active layer 21, like the waveguide layer 5, is an MQ composed of an InGaAsP layer and an InP layer.
Although it has a W structure, its composition wavelength is different from that of the waveguide layer 5 in order to prevent the light oscillated in the active layer 21 from receiving a large absorption loss in the waveguide layer 5. It is set to 1.30 μm on the side. Therefore,
This portion is provided below the active layer 21 and is a relatively thick waveguide layer 5.
Forming a LOC (Large Optical Cavity) structure. A thin second'clad layer 22 made of n-InP is stacked on the upper surface of the active layer 21, and a groove extending in a direction orthogonal to the light traveling direction is formed on the upper surface of the second 'cladding layer 22. The first-order diffraction grating 23 thus formed is formed. While the second-order diffraction grating 8 of the LAD section 3 contributes to the upward diffraction of light, the first-order diffraction grating 2
3 contributes to the oscillation of the laser light.

Further, the DFB laser unit 20 has a LAD
The second cladding layer 7 made of n-InP having the same composition as that of the portion 3 and the EA modulator portion 4 includes the first-order diffraction grating 23 and the active layer 2.
1, the waveguide layer 5 and the first cladding layer 6 are laminated so as to cover them. Further, an isolation groove portion 12 similar to that between the EA modulator portion 4 and the LAD portion 3 is formed between the second cladding layer 7 of the DFB laser portion 20 and the second cladding layer 7 of the EA modulator portion 4. The air layer is interposed between the clad layers 7 and 7 so that the LAD section 3-EA is formed.
The modulator section 4 and the EA modulator section 4-DFB laser section 20 are electrically insulated from each other. Further, a laser driving electrode layer 24 is formed on the upper surface of the second cladding layer 7 of the DFB laser section 20.

Next, a procedure for manufacturing the integrated optical deflector having the above structure will be described with reference to FIGS. 6 and 7.
First, on the semiconductor substrate 2 shown in FIG.
As shown in FIG. 5, the waveguide layer 5 having the MQW structure is grown by the OMVPE apparatus. Next, as shown in FIG. 6C, after growing a thin first clad layer 6, a first insulating film 14 is formed and patterned to form a DFB.
With the first insulating film 14 left on the laser section 20 and the EA modulator section 4, the upper surface of the first cladding layer 6 corresponding to the LAD section 3 is etched to form the second-order diffraction grating 8.

After removing the first insulating film 14 left on the DFB laser section 20 and the EA modulator section 4, FIG.
As shown in FIG. 5, the second insulating film 15 is formed and patterned to leave the second insulating film 15 in the EA modulator part 4 and the LAD part 3, and the selective epitaxial method using the OMVPE apparatus is used. An active layer 21 having an MQW structure and a second 'clad layer 22 are sequentially grown on the upper surface of the first clad layer 6 corresponding to the DFB laser section 20, and a first-order diffraction grating 23 is formed on the upper surface of the second' clad layer 22 by etching. .

Then, as shown in FIG. 7E, after the second insulating film 15 left in the EA modulator section 4 and the LAD section 3 is removed, the second cladding layer 7 is grown on the entire surface. And
As shown in FIG. 7 (f), after the third insulating film 25 is formed on the upper surface of the second cladding layer 7, the third insulating film 25 is patterned so that the DFB laser unit 20 and the EA modulator unit are formed. Openings 16 and 16 are formed at the boundary portion of 4 and the boundary portion of the EA modulator portion 4 and the LAD portion 3, respectively.
Then, as shown in FIG. 7G, the isolation groove 12 is formed by etching the upper surface of the waveguide layer 5 using the patterned third insulating film 25 as a mask.
12, and after removing the third insulating film 25, the laser driving electrode layer 24, the EA modulator driving electrode layer 10 and the LAD driving electrode layer are formed on the upper surfaces of the second cladding layers 7, 7, 7 of the respective portions. The common electrode layer 11 is grown on the lower surface of the semiconductor substrate 2, and the LAD driving electrode layer 9 is patterned to form the window 13. The integrated optical deflection element 19 of the second embodiment is completed through the above procedure.

Therefore, when the integrated optical deflection element 19 is used, as shown in FIG. 8, the first power source 17 is provided between the laser driving electrode layer 24 and the common electrode layer 11 and the EA.
A second electrode is provided between the modulator driving electrode layer 10 and the common electrode layer 11.
And the third power source 26 between the LAD driving electrode layer 9 and the common electrode layer 11. Then, when a current is injected into the active layer 21 of the DFB laser unit 20 using the first power supply 17, laser oscillation occurs and single mode light is generated, and this light then passes through the waveguide layer 5 and the EA modulator unit. It is incident on 4. In the EA modulator section 4, the positive and common electrode layers are provided on the EA modulator driving electrode layer 10 side so that a reverse bias is applied to the p-type semiconductor substrate and the n-type cladding layer by using the second power supply 18. When a negative pulse voltage is applied to the 11 side, the incident light is modulated according to the pulse voltage,
Then, this light is incident on the LAD unit 3. LAD section 3
Then, when a voltage is applied to the waveguide layer 5 by the third power supply 26, the incident light is diffracted at a diffraction angle according to the applied voltage and emitted to the external space of the element 19.

The integrated optical deflector 19 of the second embodiment has the following effects in addition to the effects of the integrated optical deflector 19 of the first embodiment. That is, the integrated optical deflection element 19 of the second embodiment is provided with the DFB laser section 20 that oscillates the light incident on these in addition to the EA modulator section 4 and the LAD section 3, so that another light source is used. It is possible to emit the diffracted light, which is modulated at high speed, to the external space only by the element 19 alone without needing to Therefore, since it is not necessary to couple an external light source to the waveguide layer 5 of the integrated optical deflector 19, the coupling efficiency is low and the amount of light is insufficient, and it is necessary to prepare various coupling jigs and parts. , Etc. can be avoided.

Further, since the integrated optical deflector 19 of this embodiment employs the DFB laser as the laser element portion, it is possible to obtain a single mode laser beam and obtain a sharp diffracted beam with good convergence. it can. Therefore, it is possible to realize a highly accurate and compact system when incorporated in, for example, an optical interconnection. Furthermore, by forming a DFB laser having a relatively simple structure, for example, a DBR laser (Distributed Bragg
The manufacturing process can be simplified as compared with the case of forming a Reflector laser or a distributed Bragg reflector laser).

In both of the integrated optical deflecting elements 1 and 19 of the first and second embodiments, p-InP is used as the material of the semiconductor substrate 2, and the first, second 'and second cladding layers 6 and 2 are used.
Although n-InP is used as the material of Nos. 2 and 7, these conductivity types may be reversed, and the material is not limited to InP, and various materials may be used. Although the MQW structure waveguide layer 5 using InGaAsP / InP is used as the waveguide layer, it may be simply a bulk InGaAsP layer. Further, instead of the integral waveguide layer 5 in these examples. Alternatively, the waveguide layers formed separately in the respective element portions 3, 4 and 20 may be coupled to each other by using various coupling structures such as a LOC structure and a butt joint structure.

Further, the clad layer may be a single clad layer instead of the two clad layers of the first clad layer 6 and the second clad layer 7 having a small thickness. In this case, the waveguide layer is used. It is desirable to provide the second-order diffraction grating 8 on the upper surface of the waveguide layer 5 in order to avoid a distance between the fifth-order diffraction grating 5 and the second-order diffraction grating 8. The electrode layer formed on the lower surface side of the semiconductor substrate 2 is not formed in the common electrode layer 11 but is formed individually in each of the element portions 3, 4 and 20, or each of the element portions 3, 4, and 2.
The insulation state of 0 may be replaced by maintaining an insulating film for partitioning each part instead of the groove. Regarding the deflection of light, instead of applying a voltage between the LAD drive electrode layer 9 and the common electrode layer 11 of the LAD section 3, a method of injecting a current through these electrode layers 9 and 11 is also used. Deflection is possible.

In the second embodiment, the DFB laser is used as the laser element section, but instead of this, the DBR is used.
Single mode light can be obtained even by using a laser, and a unique effect can be obtained when the single mode light as described above is used. Further, although a single mode light cannot be obtained, a laser element having another structure such as a general Fabry-Perot structure in which two parallel plate reflecting mirrors are opposed to each other may be formed.

Two examples in which the integrated optical deflection element is applied to optical interconnection in a large computer will be described below with reference to FIGS. 9 to 11. FIG. 9 shows the first
It is a figure which shows the system of an application example, and is an example which uses the integrated type optical deflection element 1 of 1st Example as an optical switching element when transmitting an optical signal from the motherboard 27 to the child board 28.

On the mother board 27, the integrated type optical deflector 1
Is installed so that an optical signal to be transmitted to the slave board 28 is input to the integrated optical deflection element 1. Further, on the mother board 27, an optical deflection signal circuit 29 for inputting the optical deflection signal to the LAD unit 3 of the integrated optical deflection element 1 and an EA modulator of the integrated optical deflection element 1 for the optical modulation signal. An optical modulation signal circuit 30 for inputting to the unit 4 is provided.

A child board 28 is installed above the mother board 27. Child board 28 has A, B,
Four circuits C and D are formed, and each circuit A, B,
Photodiodes PD1, PD2, PD for receiving the optical signal transmitted from the mother board 27 are shown in C and D.
3 and PD4 are provided respectively. Then, these photodiodes PD1, PD2, PD3, PD4 are
When the light emitted from the integrated optical deflection element 1 on the mother board 27 is deflected, it is arranged in parallel within the range where the light S ₁ , S ₂ , S ₃ , S ₄ reaches.

Therefore, according to the system of this application example, when the optical signal and the optical deflection signal are synchronously input to the integrated optical deflection element 1, the light S emitted from the integrated optical deflection element 1 is output. ₁ , S ₂ , S ₃ , and S ₄ are photodiodes PD 1 and PD of any one of the four photodiodes at every minute time.
2, PD3, PD4 can be configured to be incident while being switched. That is, the motherboard 27
In this case, the integrated optical deflection element 1 is used for so-called optical switching, in which optical signals in the form of a series are distributed to the four circuits A, B, C and D on the slave board 28 at every minute time. Can be realized with the existing system.

In the present system, the integrated optical deflection element 1 having the EA modulator unit 4 is used, so that the optical modulation signal is synchronized with the optical deflection signal so that the EA is interlocked with the switching by the LAD unit 3. The modulator unit 4 is driven, and EA
By using the modulator unit 4 for the purpose of temporarily blocking an optical signal, it is possible to prevent the occurrence of an error during switching. For example, as shown in FIG. 10, it is assumed that the photodiodes that transmit the optical signal by changing the voltage input to the LAD unit 3 in stages are sequentially switched to PD1, PD2, PD3, .... Then, the voltage input to the EA modulator unit 4 is a pulse voltage having a constant frequency, but a constant voltage is continuously applied for a constant time t ₁ immediately after switching, for example, on the order of nsec (10 ⁻⁹ seconds). And Then, during this period, light is continuously absorbed in the EA modulator unit 4, so that the optical signal is cut off. In this way, when switching, the optical signal is always cut off for a certain time t ₁ .
If you switch the photodiode in the meantime,
It is possible to eliminate the possibility that an error occurs in the received signal of each photodiode.

On the other hand, the EA modulator section 4 of the integrated optical deflector 1 can also be used for the purpose of high speed modulation of an optical signal. That is, if the pulse voltage input to the EA modulator unit 4 in FIG. 10 is of the order of, for example, psec (10 ⁻¹² seconds), the psec which cannot be obtained by the spatial light deflector without the EA modulator unit 4 is obtained. Since high-speed modulation on the order is possible, it is possible to perform optical information transmission in the ultra-high band of 1 Tbit / cm ² · sec order. In this way, by using the integrated optical deflection element 1 in the system, it is possible to simultaneously realize both optical information transmission with few errors and high reliability and optical information transmission in an ultra-high band.

Next, FIG. 11 is a diagram showing a system of a second application example, in which the integrated optical deflector 1 of the first embodiment is used for parallel optical information transmission between two boards. is there.

Eight integrated optical deflection elements 1a, 1b, 1c, ... Are installed side by side on the transmission board 31, and these integrated optical deflection elements 1a, 1b, 1c ,. Optical signals are input respectively.
Further, the receiving board 32 is installed at a position apart from the transmitting board 31 by several mm to several cm.
16 photodiodes PD1, PD2, P
D3, ... Are arranged in an 8 × 2 array. Then, the two photodiodes PD1 and PD2 at the leftmost column are arranged in the range reached by the light emitted from the integrated light deflecting element 1a having the one leftmost element in the figure. All integrated optical deflection elements 1a,
The photodiodes PD1, PD2, PD3, ... In every two columns correspond to 1b, 1c ,.

Therefore, according to this application example, an 8-bit optical signal, for example, a signal string such as "00000001" is input in parallel to the eight integrated optical deflection elements 1a, 1b, 1c, .... In that case, when light is input to any one of the two photodiodes PD1, PD2, PD3, ... Which are arranged in a column, the light is “0” or “1”, respectively.
If it is made to correspond to the signal of, the eight-bit signal train can be instantaneously transmitted by emitting eight lights toward any one of the photodiodes according to the signal train. Immediately after transmitting the signal sequence, the next signal sequence, for example, the signal sequence “01010101” can be similarly transmitted. That is, extremely high-speed parallel optical information transmission such that information represented by a binary number of 8 bits can be transmitted in parallel at once is realized by a system using these integrated optical deflection elements 1a, 1b, 1c, .... can do.

Also in the case of the second application example, the integrated optical deflecting elements 1a, 1b, 1c, ... Having the EA modulator section 4 are used as in the case of the effect described in the first application example. As a result, it is possible to realize parallel optical information transmission with few errors and high reliability and parallel optical information transmission in an ultra-high band.

As shown in the above two application examples, by applying the integrated optical deflection element 1 to the optical interconnection in a large computer, ultra-high-speed optical switching which will be realized in the future with a compact system configuration will be realized. And parallel optical information transmission. That is, it becomes possible to realize an optical interconnection excellent in space and time.

In the above two application examples, the integrated optical deflection element 1 of the first embodiment is used and the optical signal formed outside the element is input to the integrated optical deflection element 1. Instead of this configuration, the integrated optical deflection element 19 of the second embodiment, that is, the integrated optical deflection element 19 having the DFB laser section 20 is used, and the laser light is changed by changing the current injected into the DFB laser section 20. The system configuration may be such that direct modulation is performed, or the DFB laser unit 20 emits light without performing direct modulation and the EA modulator unit 4 performs external modulation. Further, it goes without saying that the integrated optical deflection element of the present invention can be applied to various systems other than the above optical switching and parallel optical information transmission.

[0053]

As described in detail above, claim 1 is as follows.
Since the integrated optical deflection element described has a configuration in which the electro-absorption modulation element portion and the optical deflection element portion are integrally formed on the semiconductor substrate, it is necessary to apply a voltage to the waveguide layer in the electro-absorption modulation element portion. Incident light is modulated at high speed by
It is possible to diffract the light that has reached the light deflection element unit and emit it to the external space, and adjust the diffraction angle. As a result, this integrated optical deflection element can be applied to optical interconnection in, for example, a large computer to perform optical switching and parallel optical information transmission.

At this time, since the transmission and blocking of light can be controlled by the electro-absorption modulation element section, for example, when switching is performed by deflecting an optical signal by the optical deflection element section and switching to a different light receiving element position. In addition, the position can be switched after the light signal is interrupted. Therefore, it is possible to reduce crosstalk in terms of time and position and prevent an error in the received light signal. Further, since the integrated optical deflection element is provided with the electro-absorption modulation element portion, high-speed modulation on the psec order, which cannot be achieved by direct modulation of laser light, is possible, so it will be realized in the future at 1 Tbit. It can also support optical information transmission in the ultra-high band of / cm ² · sec order. In this way, by using this integrated optical deflection element, it is possible to simultaneously realize both optical information transmission with few errors and high reliability and optical information transmission in the ultra-high band.

According to the integrated optical deflection element of the second aspect, in addition to the electro-absorption modulation element section and the optical deflection element section, a laser element section for oscillating light incident on these element sections is provided. Therefore, in addition to the effect of claim 1,
It is possible to emit the diffracted light, which is modulated at a high speed by only the element itself, to the external space without requiring another light source. Then, since it is not necessary to couple an external light source to the waveguide layer of the integrated optical deflector, it is necessary to prepare various coupling jigs and parts that cause insufficient light quantity due to low coupling efficiency.
It is possible to realize an efficient integrated optical deflection element without causing problems such as the above.

Further, according to the integrated type optical deflection element of the third aspect, since the laser element portion is formed as a distributed feedback laser element or a distributed Bragg reflector type laser element, a single mode light is emitted. It is possible to obtain sharp diffracted light with good convergence. Therefore, it is possible to realize a highly accurate and compact system when incorporated in, for example, an optical interconnection.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an integrated optical deflection element that is a first embodiment of the present invention.

FIG. 2 is a diagram showing the first half of the manufacturing process of the integrated optical deflector of the embodiment.

FIG. 3 is a diagram showing the latter half of the same.

FIG. 4 is a diagram showing a state in which the integrated optical deflector is used.

FIG. 5 is a vertical cross-sectional view showing an integrated optical deflection element that is a second embodiment of the present invention.

FIG. 6 is a diagram showing the first half of the manufacturing process of the integrated optical deflection element of the example.

FIG. 7 is a diagram showing the latter half of the same.

FIG. 8 is a diagram showing a state in which the integrated optical deflector is used.

FIG. 9 is a diagram showing a first application example in which the integrated optical deflector of the first embodiment is applied to an optical switching system.

FIG. 10 is an L-shaped integrated optical deflector in the same application example.
It is a figure which shows the relationship of the voltage pattern each input into an AD part and an EA modulator part.

FIG. 11 is a diagram showing a second application example in which the integrated optical deflection element of the first embodiment is applied to a parallel optical information transmission system.

[Explanation of symbols]

1, 19 ... Integrated optical deflection element, 2 ... Semiconductor substrate, 3 ... L
AD section (optical deflection element section), 4 ... EA modulator section (electroabsorption modulation element section), 5 ... Waveguide layer, 6 ... First clad layer (clad layer), 7 ... Second clad layer (clad layer) , 8 ...
Second-order diffraction grating, 9 ... LAD driving electrode layer (upper electrode layer), 10 ... EA modulator driving electrode layer (upper electrode layer),
11 ... Common electrode layer (lower electrode layer), 12 ... Isolation groove portion, 13 ... Groove portion, 20 ... DFB laser portion (laser element portion), 21 ... Active layer, 22 ... Second 'clad layer (clad layer), 23 ... First-order diffraction grating, 24 ... Laser driving electrode layer (upper electrode layer)

Claims (3)

[Claims] 1. An electro-absorption modulation element portion for modulating incident light and an optical deflection element portion for deflecting the light incident from the electro-absorption modulation element portion and emitting the light to an external space are integrated and formed on a semiconductor substrate. And a waveguide layer penetrating the electro-absorption modulation element section and the optical deflection element section on a semiconductor substrate, wherein the electro-absorption modulation element section is formed on the waveguide layer. A clad layer formed on the clad layer, an upper electrode layer formed on the upper surface of the clad layer, and a lower electrode layer formed on the lower surface of the semiconductor substrate. A clad layer formed on the upper side, a second-order diffraction grating formed on the upper surface of the waveguide layer or the clad layer for diffracting light upward, and a second-order diffraction grating formed on the upper surface of the clad layer to generate the diffracted light. Window for emitting to external space And a lower electrode layer formed on the lower surface of the semiconductor substrate, wherein the light deflection element section and the electro-absorption modulation element section are electrically insulated from each other. Integrated light deflection element. 2. A laser element section for oscillating light,
An electro-absorption modulation element section that modulates the light incident from the laser element section and an optical deflection element section that deflects the light incident from the electro-absorption modulation element section and emits the light to an external space are integrally formed on a semiconductor substrate. And a waveguide layer penetrating the laser element section, the electro-absorption modulation element section, and the optical deflection element section is formed on a semiconductor substrate. An active layer formed on the waveguide layer, a clad layer formed on the active layer,
1 formed on the upper surface of the active layer or the clad layer
A second diffraction grating, an upper electrode layer formed on the upper surface of the cladding layer, and a lower electrode layer formed on the lower surface of the semiconductor substrate, wherein the electro-absorption modulation element section is formed on the waveguide layer. A cladding layer formed, an upper electrode layer formed on an upper surface of the cladding layer, and a lower electrode layer formed on a lower surface of the semiconductor substrate, wherein the optical deflection element section is an upper portion of the waveguide layer. And a second-order diffraction grating formed on the upper surface of the waveguide layer or the clad layer for diffracting light upward, and on the upper surface of the clad layer for diffracting the diffracted light to the outside. An upper electrode layer having a window portion for emitting light into a space; and a lower electrode layer formed on the lower surface of the semiconductor substrate, wherein the laser element portion, the electroabsorption modulator element portion, and the light deflection element portion are respectively provided. Electrically isolated Integrated optical scanning element characterized by being. 3. The integrated optical deflection element according to claim 2, wherein the laser element section is formed as a distributed feedback laser element or a distributed Bragg reflector type laser element. element.