JPH03186821A - Optical switch - Google Patents

Abstract

PURPOSE:To obtain the optical switch having respectively two pieces of optical waveguides on input and output sides by forming the switch of two pieces of the semiconductor optical waveguides intersecting at a specified intersecting angle and providing refractive index control parts respectively in the semiconductor optical waveguides near the intersected part. CONSTITUTION:This switch is formed of two pieces of the semiconductor optical waveguide parts D1 to D4 intersecting with each other at the intersection angle theta deg.(where theta<90 deg.) and the refractive index control parts F1 to F4 are provided in the respective semiconductor optical waveguide parts D1 to D4 near the intersected part E. The propagation to the light waves to the respective optical waveguide parts D1 to D4 is stopped by operating the refractive index control parts F1 to F4 provided on the respective optical waveguide parts D1 to D4. The respective connections can be changed between the respective optical waveguide parts D1 to D4 by properly operating the respective refractive index control parts F1 to F4. The optical switch having two pieces of the optical waveguide parts D1 to D4 respectively on the input and output sides is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical switch incorporated in an optical communication system, and more particularly to an optical switch capable of bidirectional communication.

(Prior Art) An optical communication system incorporates an optical switch. Among these optical switches, a Y-branch optical waveguide type optical switch made of a semiconductor material is shown in FIG. 3, which is a perspective view of FIG. explain.

In the figure, a buffer layer 3 made of an n+ type semiconductor is placed on a substrate layer 2 made of an n+ type semiconductor and having a lower electrode l formed on its back surface. Lower cladding layer 4 made of n+ type semiconductor.
Core layers 5 made of n-type semiconductor are sequentially laminated to a predetermined thickness.

On the core layer 5 is an upper cladding layer 6. made of a p+ type semiconductor. A cap layer 7 starting from an n-type semiconductor is sequentially laminated to form a ridge-shaped optical waveguide which branches into Y branches at a branching angle θ. Their entire surfaces are covered with an insulating thin film 8.

Here, the main optical waveguide A is an input port, and the two Y-branched branch side optical waveguides Bl and B2 are output ports, respectively.

In the branch side optical waveguides Bl and B2, a part of the insulating thin film located near the branch part is removed in the form of a slit, and a window 8a (8b) is formed there. And these windows 8a,
From 8b onward, a predetermined material is deposited, for example, by vapor deposition over them and in contact with the cap layer, thereby forming upper electrodes 9a and 9b.

The upper electrode 9a in the branch optical waveguide Bl, B2,
9b is formed at the refractive index control portion CI of this optical switch.
, C2.

In the case of this optical switch, when a light wave is input from the main optical waveguide A without operating the refractive index controller CI+02,
The light waves are emitted from the branch optical waveguides Bl and B2 with equal output power.

For example, when a predetermined current is injected from the upper electrode 8a or a predetermined voltage is applied, the refractive index of the core layer in the refractive index control section CI decreases, causing light waves in the branch optical waveguide B1 to propagation stops completely. That is, the light wave incident from the main optical waveguide A is transmitted to the branch optical waveguide B.
It emits only from 2.

In this way, this optical switch can realize switching of the optical path, that is, a switching operation, by operating the refractive index controllers C1 and C2 as described above.

(Problem to be Solved by the Invention) By the way, in the case of this Y-branch type optical switch, the main optical waveguide A can be connected to either one of the branch optical waveguides Bl and B2, so-called 1 input/2 outputs. Functions as a light switch.

Therefore, this optical switch alone cannot form an optical switch having two optical waveguides on the input side and two optical waveguides on the output side.

An object of the present invention is to provide an optical switch having two optical waveguides on each input and output side by utilizing the switching operation of the Y-branch type optical switch described above.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in the present invention, two semiconductor optical waveguides that intersect at an intersection angle θ° (however, θ<90°) to form an intersection are provided. An optical switch is provided, characterized in that each of the semiconductor optical waveguides near the intersection is provided with a refractive index control section.

(Function) By operating the refractive index control section provided on each optical waveguide section extending in all directions from the intersection, propagation of light waves to each optical waveguide section can be stopped. Therefore, by operating each refractive index control section appropriately, the mutual connections between the optical waveguide sections can be changed, and as a result, any optical path can be formed.

(Example) An example of the present invention will be described below based on the perspective view of FIG.

In this optical switch, two semiconductor optical waveguides intersect in an X-shape at an intersection angle θ (θ<90°) to form an intersection E. In the vicinity of this intersection E, each of the four optical waveguide portions D II D 2° D3. Above D4, there is a refractive index control unit Fl + Fz lF3. F4 is formed. The cross-sectional structure of this optical switch is the same as that of the conventional Y-branch optical switch shown in FIGS. 2 and 3.

In this optical switch, assuming that the optical waveguide section DIrD2 side is the input side and the optical waveguide section Da, D< side is the output side, the refractive index control section Fl + F2 +Fll, F4
By this operation, the following optical waveguide sections can be connected and optical paths can be selected.

Refractive index control section F2. When F3 is operated at the same time, the light wave incident from the optical waveguide portion D1 can be emitted from the optical waveguide portion D4, and the refractive index control portions F1. When F4 is operated at the same time, the light wave incident from the optical waveguide portion D2 can be emitted from the optical waveguide portion D3.

Refractive index control section F2. When F4 is operated at the same time, the light wave incident from the optical waveguide section D3 can be made to exit from the optical waveguide section D3, and when the refractive index control sections F+ and F3 are operated simultaneously, the light wave incident from the optical waveguide section D2 can be made to exit from the optical waveguide section D2. The light can be emitted from the optical waveguide portion D4.

(Effects of the Invention) As is clear from the above explanation, the optical switch of the present invention has the following effects:
By appropriately operating the refractive index control section formed in each optical waveguide section, each optical waveguide section can be connected appropriately, and any optical path can be formed.

As a result, the optical switch of the present invention has a high extinction ratio of 4°, is extremely simple to manufacture, and has great industrial value.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an optical switch according to an embodiment of the present invention, Fig. 2 is a perspective view of a Y-branch type optical switch, and Fig. 3 is a perspective view of an optical switch according to an embodiment of the present invention.
- It is a sectional view along the I line. l...lower electrode, 2...n++ semiconductor substrate, 3...
・n+ type semiconductor buffer layer, 4...n+ type semiconductor lower cladding 1 layer 5...n- type semiconductor core layer, 6...p
+-type semiconductor upper cladding 1 layer 7...n-type semiconductor cap layer, 8...insulating thin film, 8a, 8b...window, 9a
, 9b... Upper electrode, A... Main optical waveguide, B+, B
2... Branch optical waveguide, C+, C2, F+, F2
, F3. F4... refractive index control section, Dt, Dt,
D3, Dt... optical waveguide portion, E... intersection.

Claims (1)

[Claims] It consists of two semiconductor optical waveguides that intersect at an intersection angle θ° (however, θ<90°) to form an intersection, and each of the semiconductor optical waveguides near the intersection is provided with a refractive index control section. An optical switch characterized by: