JPH08129195A - Optical switch module - Google Patents

Abstract

PURPOSE: To provide an optical switch module which enables optical interconnection of high accuracy. CONSTITUTION: This optical switch module has one input port 3, an optical deflecting element 2 for spatially deflecting the incident light signals thereon and plural output ports 8 for taking out the exit light thereof. This optical deflecting element 2 has a waveguide layer formed on a semiconductor substrate, a diffraction grating which is formed thereon and takes out the secondary diffracted light of the light transmitted through the waveguide layer outside, a clad layer formed thereon and electrodes which are formed on this clad layer and the rear surface of the substrate and function to variably control the refractive index of the waveguide layer. The optical diffraction element 2 is mounted on a module base 1 in such a manner that the deflection of the exit light thereof is executed within the plane parallel with the module base 1. In addition, a microlens array 6 for introducing the exit light of the optical deflecting element 2 to the output ports 8 according to its deflection angle and a waveguide element 7 are mounted on the module base 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switch module used for optical transmission switching in an information processing system or a communication system using optical signals.

[0002]

2. Description of the Related Art In recent years, in the field of information processing, for example, development of so-called optical interconnection technology that uses optical signals for information transmission between boards and processors in a large computer has been advanced. In this optical interconnection, an optical switching element for spatially switching optical signals and an element for controlling parallel optical information transmission are desired. An optical waveguide element having a diffraction grating formed therein is promising as such a space-type optical deflecting element, but conventionally known ones can only emit light to the external space, and spatial light switching, etc. Can't handle.

[0003]

However, even if the spatial deflection element capable of controlling the deflection angle of the emitted light can be realized, it is intended to use it as an optical switching element having a spatial address function between boards. Then, a big problem occurs in implementation. For example, consider a case where a spatial light deflector is arranged on a main board, and the emitted light is deflected and transmitted to a light receiving array or the like on a facing sub board at a distance of several cm. At this time, even if the spot diameter of the light beam is set to about 1 mm, extremely high-precision alignment is required between the mounting position of the light deflection element on the main board and the mounting position of the light receiving element array on the sub board. Considering the alignment accuracy when these boards are fitted into the stack, such a spatial optical interconnection is not very practical.

The present invention has been made in view of such circumstances, and an object thereof is to provide an optical switch module which enables highly accurate optical interconnection.

[0005]

SUMMARY OF THE INVENTION The present invention is an optical switch module including an optical deflecting element for spatially deflecting an incident optical signal, the optical deflecting element comprising a semiconductor substrate and a substrate. A waveguide layer formed in, a diffraction grating for extracting the second-order diffracted light of the light formed on the waveguide layer and transmitted through the waveguide layer to the outside, and a clad layer formed on the diffraction grating, This clad layer has an electrode for variably controlling the refractive index of the waveguide layer provided on the back surface of the substrate, and the optical deflection element is on a module base, and the deflection of the emitted light is the module base. It is characterized by being mounted so as to be performed in parallel planes.

According to the present invention, one input port to which an optical signal is incident, an optical deflecting element for spatially deflecting the optical signal incident on this input port, and a plurality of outgoing light from the optical deflecting element are extracted. An optical switch module having an output port of the semiconductor device, the optical deflection element, a waveguide layer formed on the semiconductor substrate, and a waveguide layer formed on the waveguide layer and transmitted through the waveguide layer. For variably controlling the refractive index of the diffraction grating for extracting the second-order diffracted light of the light, the cladding layer formed on the diffraction grating, and the cladding layer and the waveguide layer provided on the back surface of the substrate. An electrode, the light deflection element is mounted on a module base such that the emitted light is deflected in a plane parallel to the module base, and the light emitted from the light deflection element is placed on the module base. To Focusing means for directing said plurality of output ports in accordance with the deflection angle of it is characterized in that it is mounted.

[0007]

According to the present invention, the space-type light is an optical deflecting element for emitting the second-order diffracted light to the outside, and the deflection angle can be varied by controlling the refractive index of the waveguide layer by an external bias. A deflection element is used. Then, the spatial light deflector is made into a switch module having one input port and a plurality of output ports so that the emitted light is deflected in a plane parallel to the module base. The optical axis alignment within the switch module can be easily and highly accurately performed as compared with the above-mentioned inter-board alignment.
When the optical switch module of the present invention is mounted on a board, spatial optical switching is performed within the board. For example, by coupling with an opposing board with an optical fiber, etc. Compared to the optical switching method, it does not require difficult alignment.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an optical switch module according to an embodiment of the present invention. This switch module has one input port 3 for inputting an optical signal and a plurality of output ports 8 for outputting an optical signal. On the module base 1, as a spatial light deflecting element 2 for spatially deflecting the optical signal supplied from the input port 3 and means for condensing the output light S from the deflecting element 2 at the output port 8, The microlens array 6 and the waveguide element 7 are mounted. The microlens array 6 is, for example, a Selfoc lens array.

In the figure, an optical fiber is shown as the input port 3 and an optical fiber array is shown as the output port 8 as well, but these may be connectors capable of coupling optical fibers and the like. The spatial light deflector 2 is capable of variably controlling the deflection angle by applying an external bias. The details will be described later, but as shown in the figure, the output light S has a predetermined angle within a plane parallel to the module base 1. It is arranged so that it can be deflected in the range of θ. The module is provided with voltage application terminals 4a and 4b so that an external power source 5 can be connected thereto.

Microlens array 6 and waveguide element 7
Is provided to reduce the beam diameter of the output light S from the deflection element 2 and couple it to one of the output ports 8, but the waveguide element 7 is not always necessary.

FIG. 2 is a perspective view showing the spatial light deflector 2 by cutting it out. The optical deflection element 2 has a waveguide layer 21 formed on the substrate 20 and a diffraction grating 23 formed at the interface between the two clad layers 22a and 22b laminated on the waveguide layer 21. . The waveguide layer 21 has, for example, a multiple quantum well (MQW) structure. The diffraction grating 23 is transmitted through the waveguide layer 21, for example, 1.3.
The refractive index and the grating pitch of the waveguide layer 21 and the medium in the vicinity thereof are set so that the second-order diffracted light of μm light can be extracted in the direction perpendicular to the substrate surface.

When, for example, p-type InP is used as the substrate 20, the waveguide layer 21 includes i-type InP and InGaAsP.
InP / InGaA in which each layer is alternately stacked by about 10 nm
It is composed of the sP layer. The absorption wavelength is, for example, 1.
It is set to 15 μm. First clad layer 22a on this
Is an n whose absorption wavelength is set to a shorter wavelength side than the waveguide layer 21.
Type InGaAsP layer and the second cladding layer 22b is n
Type InP layer. These conductivity types can be reversed.

By setting the composition as described above, the light deflection element 2
Then, from the waveguide layer 21 to the first cladding layer 22a and the second cladding layer 22a.
The refractive index distribution is formed so that the refractive index becomes smaller in the order of the clad layer 22b. The diffraction grating 23 embedded in the optical deflecting element 2 is formed on the surface of the thin first clad layer 22a and is arranged at a position extremely close to the waveguide layer 21. The portion of the light exuding is coupled to the diffraction grating 23.

An electrode 24 having a light extraction window 25 is formed on the surface of the clad layer 22, and an electrode 26 facing the electrode 24 is formed on the back surface of the substrate 20. By applying a positive voltage on the electrode 24 side between the electrodes 24 and 26, the refractive index in the vicinity of the diffraction grating 23 of the optical deflector 2 is controlled by the so-called electro-optical effect due to the internal electric field. This controls the diffraction angle of the secondary diffraction light from the diffraction grating 23 due to the coupling from the waveguide layer 21, that is, the deflection angle of the light extracted through the window 25.

As described above, the optical switch module according to this embodiment has one input port and a plurality of output ports, and the spatial light deflection element is integrated with the microlens array or the like, so that the spatial light is generated in the module. Optical switching is performed. The optical axis alignment within the module is easy. The optical coupling between the board on which this module is mounted and another board can be performed by an optical fiber. Therefore, unlike the method in which optical coupling between boards is spatially performed, highly accurate alignment between boards is not required.

Further, there is no problem such as a change in the external environment after mounting, such as a time-dependent optical axis shift due to the influence of temperature fluctuation or vibration, a decrease in coupling efficiency, and an increase in signal error rate, and a highly reliable optical interconnection. Will be possible.

[0017]

As described above, according to the present invention, the spatial light deflector capable of changing the deflection angle by the external bias is such that the emitted light is deflected in the plane parallel to the module base. It is a switch module with one input port and multiple output ports. Optical axis alignment in the switch module can be easily performed with high accuracy. And if the optical switch module of the present invention is mounted on a board, spatial optical switching is performed within the board,
By connecting the opposing boards with an optical fiber or the like, difficult alignment is not required.

[Brief description of drawings]

FIG. 1 shows the configuration of an optical switch module according to an embodiment of the present invention.

FIG. 2 shows a configuration of an optical deflecting element used in the example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Module base, 2 ... Spatial light deflection element, 3 ... Input port, 4a, 4b ... Voltage application terminal, 5 ... External power supply,
6 ... Microlens array, 7 ... Optical waveguide element, 8 ... Output port.

Claims (2)

[Claims] 1. An optical switch module comprising an optical deflecting element for spatially deflecting an incident optical signal, wherein the optical deflecting element comprises a semiconductor substrate and a waveguide layer formed on the substrate. , A diffraction grating for extracting the second-order diffracted light of light transmitted through the waveguide layer formed on the waveguide layer, a clad layer formed on the diffraction grating, and the clad layer and the back surface of the substrate. An electrode for variably controlling the refractive index of the waveguide layer provided, and the light deflection element is arranged on a module base so that the emitted light is deflected in a plane parallel to the module base. An optical switch module that is installed in. 2. An input port into which an optical signal is incident, an optical deflecting element for spatially deflecting the optical signal incident into the input port, and a plurality of output ports for extracting light emitted from the optical deflecting element. An optical switch module comprising: a semiconductor substrate; a waveguide layer formed on the substrate; and a light beam transmitted through the waveguide layer formed on the waveguide layer. A diffraction grating for extracting the second-order diffracted light to the outside, a clad layer formed on the diffraction grating, and an electrode for variably controlling the refractive index of the clad layer and the waveguide layer provided on the back surface of the substrate are provided. The optical deflection element is mounted on a module base such that the emitted light is deflected in a plane parallel to the module base, and the emitted light of the optical deflection element is deflected on the module base. On the corner Optical switch module, wherein the Flip focusing means for guiding said plurality of output ports are mounted.