JPH02136805A - Waveguide type photoelectric matrix switch - Google Patents

Abstract

PURPOSE:To miniaturize a photoelectric matrix (OEM) switch device as a whole and to assure the safety of the device by propagating optical signals through waveguides formed in a transparent dielectric base plate and integrating light detecting electronic circuits respectively composed of photodetector and electronic switches on the same base plate. CONSTITUTION:Optical signals converted from inputted electronic signals by means of semiconductor lasers 501-520 are propagated through waveguides 101-120 formed in a base plate 1 and part of the rays of light is reflected by optical means respectively formed in the waveguides 101-120 of 40 pieces of V-grooves 201-240 and gold thin films 4 and the light which is made incident on 20X40 pieces of photodetector 36 is taken out. Then, by controlling the gate voltage applied across a TFT and turning on a desired photodetector in the photodetector group connected in parallel with a certain output electrode, desired inputted electronic signals are reproduced to the output electrode. Therefore, this OEM switch can be miniaturized and the safety of the switch can be secured.

Description

[Detailed Description of the Invention] <Industry” Second Field of Application> The present invention applies to a plurality of applications! Do you care about multiple issues? The present invention relates to an optoelectronic matrix switch for arbitrarily distributing light to optical signal lines, and in particular to a waveguide optoelectronic matrix switch integrated on one substrate.

<Conventional technology> Conventionally, multiple electrical signals (particularly video signals) are
As a device for distributing to the T line, a device using only electronic circuits was known.
An art is known in which the 11'X signal is once converted into an optical signal by a light emitting element, and this light is distributed by an optical matrix switch made of a LiNb0a substrate.

Also, change it to light number 13 with a light emitting element,
A photoelectronic matrix switch (hereinafter abbreviated as OEM switch) allows this light to be received by multiple photodetecting elements, turns on only the photodetecting element r that receives the desired optical signal, and receives that optical signal. was known.

As an OEM switch, the one shown in FIG. 6 was known. This is a Topical Meeting on by one of the inventors, Elmer Hichhara et al.
Optical Fiber Communic
ation, 1979, Washingto
n This is a report of DC1 paper number PD2. Regarding optoelectronic switching elements, U.S. Patent No. 4369 by the same person
There are 371. In this device, multiple electrical signals are each converted into optical signals using multiple laser diodes.
Propagates through an optical transmission line or space. A plurality of photodiodes that receive a portion of those optical signals are arranged, and their output terminals are connected to a common electrode via a buffer amplifier to create a plurality of photodiode array groups. A bias voltage was applied to only the detection elements to turn them on, and one output electrical signal was obtained for each photodiode array group.

In this device, the optical signal is received only by the photodetector element that is in the on state, and the bias of the other elements is turned off, so the output electrical signal is almost zero, so the isolation of unnecessary TIF signals is extremely high. It had the advantage of

<Problems to be Solved by the Invention> Conventional devices using only electronic circuits have unavoidable drawbacks such as the inability to achieve very high isolation and the drawbacks that the circuits are complex and large. In addition, optical matrix switches have the disadvantage that they are difficult to manufacture,
In addition to the drawback of not being able to achieve high isolation, it also had the fatal drawback of being troublesome to adjust the voltage for driving each optical switch element and being temperature dependent.

On the other hand, the above-mentioned OEM switch has the advantage of providing sufficient isolation, but it propagates light in space, making it difficult to downsize and lacking sufficient stability.

<Means for Solving the Problems> In order to solve the above-mentioned problems of OEM switches that have essentially excellent characteristics, the present invention propagates optical signals in a waveguide of a transparent dielectric substrate, and A photodetection electronic circuit consisting of a detection element and an electronic switch is integrated on the same substrate φ Transparent dielectric substrates that can be used in the present invention include glass substrates, LiNbO3 substrates, silicon substrates, etc. are photodiodes and photoconductive elements formed on compound semiconductor substrates such as amorphous silicon, polycrystalline silicon, single crystal silicon, and GaAs;
There is a combination of a photodetector element such as an avalanche diode and an electronic switch using a transistor.

<Embodiment> FIG. 1 is a diagram showing a substrate and an optical waveguide section of an OEM switch according to an embodiment of the present invention. The substrate l is suitable for ion exchange.
It is a 0 cm square glass substrate. The substrate 1 has 20 optical waveguides 101, 102, 103, 1041. ,．． 120 are formed by ion exchange at equal intervals. Waveguide 101-
Semiconductor lasers 501 to 520 are coupled to 120, respectively. The waveguides 101-120 have a cross-sectional diameter of 1
00 μm multimode waveguide. 40 lines perpendicular to these waveguides 201.2021, . 240 is formed with a dicing saw.

The tip of vII partially hangs over the optical waveguides 101-120. A gold thin film 4 is partially formed near the intersections of the waveguides 101 to 20 and the V grooves 201 to 240, respectively. A part of the light propagating through the waveguides 101 to 120 is transmitted through the V-groove 2.
It is reflected by the gold thin film 4 on 01 to 240, and is emitted downward as extracted light.

On the opposite side of the substrate 1, there are 20×40 photodetection electronic circuits 30 each consisting of a thin film transistor (hereinafter abbreviated as TPT) made of a thin film material and a photodetection element.

FIG. 2 is a cross-sectional view at the intersection of the waveguide 101 and Vfi 201 in FIG. The photodetector element 36 and the TFT semiconductor 33 are amorphous silicon manufactured by CVD. The photodetecting element 36 is a light receiving element that utilizes the photoconductive effect of a semiconductor. Gate electrode 31 and TFT semiconductor 33
0 is insulated by a 5raNz thin limb 32. A source electrode 34 and a drain electrode 3 are provided on both sides of the TFT semiconductor 33.
There are 5. The source electrode 34, drain electrode 35 and output electrode 38 are thin films of gold. The gate electrode 31 and the transparent electrode 37 are made of indium tin oxide (ITO), and the transparent electrode 37 is connected to the output electrode 38. The relationship between these f: children is as shown in the wiring diagram in FIG.

FIG. 4 shows the TI” T located below the optical waveguide 102.
Source electrode: 34, gate'I4 pole 31, drain N
Poles: 35, transparent electrode 37ti,! +1 output? [3B(
7) It is a diagram showing details of wiring. FIG. 5 is a diagram illustrating the M and pole wirings seen from the photodetection electronic circuit 30 side.

A load resistor 51 and a buffer 7 amplifier 5' are connected to the output fJt pole 38.
, 2 are connected. Twenty photodetection electronic circuits 30 are connected to the output electrode 38 and the source electrode 'L34. The gate is the pole;) 1 is the entire thin film gate electrode wiring;]
I'm trying to connect to 9. Gate electrode wiring 39 a, :39 t:+, :39 for the gate 7 of other TPTs, respectively.
c, , , , and these wirings are connected to board 1, respectively.
extends to the end of the The intersection of the gate electrode 31 and the source 1 pole 34 is insulated with a 514N3 thin HQ32-like TFT semiconductor 33-.

Now, voltage is applied to the source electrode; 34, and the photodetector element: 36
When a suitable voltage is applied to the gate pole 31 with light incident on υ, the TPT is turned on, and a photoconductive current flows between the TPT, the photodetecting element 36, and the load resistor 51, resulting in the output electrode 3F3. M pressure is generated at , and the output is taken out through the buffer amplifier 52 .

<Function> According to the present invention, the light 1 converted from the input electric signal by the semiconductor lasers 501 to 520 is converted into the light 2 whose number is on the substrate l.
The light propagates through 0 waveguides 101 to 120, and some of the light propagates through 40 grooves 2 formed in waveguides 101 to 120.
01 to 240 and an optical f-stage consisting of a gold thin wire 4, the light is reflected by q.
Ni people! 114.

The gate voltage applied to T F T is II i31! By doing this, a desired photodetecting element in a group of photodetecting elements connected in parallel to a certain output electrode is turned on. It is possible to reproduce the true signal. At this time,
Arbitrary input electricity (No. 5) is distributed to each output electrode.

Generally, the number of human-powered electric signals is N, and the number of output electric signal lines is M.
Then, an N×M OEM switch for electrical signal distribution is obtained. In the example, the frequency bandwidth is 100 MH2, and the inter-channel isolation is 70 + in? ) The OEMEM switch 1 method of the example was small with 10(.

<Effects of the Invention> The basic configuration of the present invention is that of the conventional space propagation type (
, ) is the same as the E M switch, and has 7x number of inputs i
! It is possible to arbitrarily switch between 1i4';'+ and a plurality of output electric signal lines. On this occasion,! Qi-9-? t%
Since the photodetecting element is electrically switched using the conversion of
It has been reported that the isolation between the desired optical signal to be received by each photodetecting element r group and the unnecessary optical signal is high. Furthermore, in the present invention, since the waveguide, photodetector, and electronic circuit are integrated on the same substrate, the entire structure can be made compact, and the number of individual optical components can be reduced to 6.
You can get it at a low price. At the same time, the light is emitted outside the X-plate, but since the photodetecting elements are integrated on the substrate,
The stability of the EM switch equipment can be ensured.

In addition, in the example, the reflecting mirror was constructed with ■grooves and the Kanpo armpit, but other methods may be used. For example, a branch waveguide for extraction light may be created and all the light from the waveguide may be extracted. Alternatively, the grooves may be formed by hot pressing. Also, instead of amorphous silicon, use polycrystalline silicon! 1i crystal silicon or the like may also be used. There may be various lJ methods for electrical wiring within a board other than those in the embodiments.

[Brief explanation of the drawing]

Figures 1 to 5 show waveguides according to the present invention! l'I OE
An example of the M switch is shown in Figure 1. Figure 1 is a plan view seen from the side with a wide waveguide, and Figure 2 is a plan view of the waveguide 10.
1. V groove 201. FIG. 3 is a wiring diagram showing the electrical wiring between the photodetecting element and the TPT, and FIG. Photodetection electronic circuit: 30 detailed wiring diagrams,
Figure 5 shows waveguide of 1°! FIG. 6 is a plan view showing the Tl pole wiring of the OEM switch, and is a configuration diagram of the conventional (7) OEM switch. In the figure, 1...substrates 101, 102, 103, 1041. ,．． 120...
・Optical waveguide, 201, 2025. , , 240---Vllll
l, 4...Gold thin film 30...Photodetection electronic circuit 34...Source electrode 39...Gate electrode wiring 51...Load resistor 52...Buffer amplifier. Figure 4 Figure 4 Figure 1 Itozo d:? 40 Representation of the January 1, 1939 Case Patent Application No. 63-291868 Name of the Invention Waveguide Photoelectronic Matrix Switch 3゜ Person Who Amends 4゜ Relationship with the Case 4゜ Address of Patent Applicant 4-8 Domine-cho, Higashi-ku, Osaka-shi, Osaka Name
(400) Nippon Sheet Glass Co., Ltd. Representative name: Tatsuji Nakajima

Claims (1)

[Claims] N optical waveguides formed on a transparent dielectric substrate, each coupled to a light emitting element, and M optical waveguides each having a function of extracting a part of the guided light from the waveguide as readout light. N×M photodetecting elements formed on the opposite side of the substrate to the side where the waveguide exists and each receiving the readout light, and disposed close to each of the photodetecting elements and electrically coupled The output electrodes of the photodetecting elements each receiving the readout light of the N waveguides are commonly wired to form a group of M photodetecting elements. A waveguide optoelectronic matrix switch featuring