JPH06140699A - Optical angular velocity detector and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To simplify and miniature the entire constitution in an optical angular velocity detector. CONSTITUTION:Laser beams LB1, LB2 propagated in each direction of a ring laser part 2 are sent to a light-receiving part 4 through an optical wave guide path 3 which is optically coupled with the ring laser part 2 and the ring laser part 2 being a semiconductor laser structure is formed on a substrate 1, and then a first clad layer of the optical wave guide path 3 is formed on the ring laser part 2 and the substrate 1, and on the first clad layer in a part formed on the substrate 1, a core of the optical wave guide path 3 having a light refractive index different therefrom is formed and further a second clad layer of the optical wave guide path 3 is formed therefrom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical angular velocity detector for detecting an angular velocity acting on a detector body and a manufacturing method thereof.

[0002]

2. Description of the Related Art Recently, laser light has been propagated in different directions in a ring laser section, and when an angular velocity acts on the ring laser section, the beat of the laser light in each direction changes accordingly. Focusing on, the laser light in each direction is extracted from the ring laser unit and given to the light receiving unit to obtain a signal corresponding to the beat of the laser light in each direction, so that the angular velocity acting on the ring laser unit is detected. An optical angular velocity detector has been developed.

Conventionally, in this type of optical angular velocity detector, an optical system is assembled to the ring laser section, and laser light in each direction is taken out from the ring laser section through the optical system to the light receiving section. I am trying to give.

[0004]

The problem to be solved is that if an optical system for taking out laser light in each direction is attached to the ring laser portion, the whole structure becomes complicated and large. In addition, the manufacturing thereof becomes complicated.

[0005]

According to the present invention, in an optical angular velocity detector, a laser in each direction propagating to a ring laser portion can be simply and miniaturized without using any optical system. Light is sent to the light receiving portion through an optical waveguide optically coupled to the ring laser portion, a ring laser portion having a semiconductor laser structure is formed on the substrate, and then the first portion of the optical waveguide is formed on the ring laser portion and the substrate. Clad layer is formed on the first clad layer in the portion formed on the substrate, and a core of an optical waveguide having a different optical refractive index from that of the clad layer is formed. The clad layer is formed so that the ring laser section and the optical waveguide optically coupled to the ring laser section are integrally formed on the same substrate.

Then, the present invention provides a step of forming a ring laser portion by etching a laser epitaxial layer having a semiconductor laser structure provided on a substrate, and a step of forming an optical waveguide on the ring laser portion and the substrate. The step of forming the first clad layer, and the core layer of the optical waveguide having a different optical refractive index from that of the first clad layer are formed, and then the core layer is etched to form the core of the optical waveguide. The ring laser section and the optical waveguide optically coupled to the ring laser section are formed on the same substrate by taking the step of forming and the step of forming the second clad layer of the optical waveguide from above.

[0007]

1 shows an example of the configuration of an optical angular velocity detector according to the present invention, in which a ring laser section 2 and an evanescent side thereof facing one side of the ring laser section 2 are provided on the same substrate 1. The optical waveguide 3 provided so as to be coupled (directional optical coupling) is integrally formed.

FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, in which the ring laser portion 2 formed on the substrate 1 and the cladding layer 31 of the optical waveguide 3 are formed on the substrate 1, and A core 32 of the optical waveguide 3 having a different optical refractive index from the cladding layer 31 is formed on the cladding layer 31 in the portion formed on the substrate 1 so as to be separated from the ring laser portion 2. Clad layer 33 of optical waveguide 3
Are formed. In the figure, 21 indicates a laser emitting layer in the ring laser section 2, and 5 indicates an electrode.

In such a structure, laser light is emitted to the ring laser section 2 in the clockwise direction indicated by the solid line in the figure and in the counterclockwise direction indicated by the dotted line in the figure by the controller (not shown). Laser oscillation in the ring laser unit 2 is controlled so that LB1 and LB2 propagate, and laser lights LB1 and LB2 in respective directions thereof are extracted by the optical waveguide 3 and sent to the light receiving diode 4 provided outside. An electric signal corresponding to the beats of the laser beams LB1 and LB2 in each direction is obtained.

At this time, the laser light LB1 propagating in the clockwise direction indicated by the solid line in the figure of the ring laser section 2 is transferred to the optical waveguide 3 and then reflected by the end surface thereof to be sent to the light receiving diode 4 in the figure. The laser light LB2 propagating in the counterclockwise direction shown by the dotted line is transferred to the optical waveguide 3 and is sent to the light receiving diode 4 as it is.

FIG. 3 shows a manufacturing process of the ring laser section 2 and the optical waveguide 3 which are integrally formed on the substrate 1.

According to the present invention, as shown in FIG. 3, a first step of forming a ring laser portion 2 by etching a laser epitaxial layer having a semiconductor laser structure provided on a substrate 1 into a predetermined pattern, The second step of forming the cladding layer 31 of the optical waveguide made of SiO ₂ on the ring laser portion 2 and the substrate 1 by the CVD method and the like, and the cladding layer 31 and the cladding layer 31 are used for optical refraction. A third step of forming a core layer 32 'made of SiO ₂ having a different ratio by a CVD method or the like;
A fourth step of forming a resist pattern 34 for forming a core on the core layer 32 'at a predetermined position separated from the ring laser section 2, and etching the core layer 32' to form the core 32 of the optical waveguide. Then, a fifth step of removing the resist pattern 34 is performed, and a cladding layer 33 made of SiO ₂ having the same optical refractive index as the cladding layer 31 is further formed on the cladding layer 31 and the core 32 by a CVD method or the like. After the formation, the sixth step of forming the electrode 5 on the bottom surface of the substrate 1 is performed.

In the ring laser section 2, as shown in FIG. 4, a buffer layer n (+) GaAs, an N layer nAlGaAs, and a light emitting layer Al are formed on a base layer n (+) GaAs.
GaAs, P layer pAlGaAs and contact layer p
It is formed by etching a normal semiconductor laser structure in which (+) GaAs is sequentially laminated by epitaxial growth into a rectangular (or triangular) ring shape.

Thus, according to the present invention, the same substrate 1
The ring laser section 2 and the optical waveguide 3 optically coupled to the ring laser section 2 can be easily integrally formed thereon.

Further, according to the present invention, when the cladding layer 31 is formed on the substrate 1, the light emitting layer 21 in the ring laser section 2 and the core 32 of the optical waveguide can face each other at the same height on the substrate. As described above, the film thickness can be easily adjusted, whereby the laser light in each direction in the ring laser unit 2 can be efficiently transferred to the optical waveguide 3, and the angular velocity can be detected accurately and reliably. Will be able to.

[0016]

As described above, in the optical angular velocity detector and the method of manufacturing the same according to the present invention, the laser beams propagating in the ring laser section in opposite directions are transmitted by any optical system as in the prior art. Without using it, it becomes possible to take out efficiently and surely by the optical waveguide provided so as to be optically coupled to the ring laser portion, and the ring laser portion and the optical waveguide can be easily integrated on the same substrate. It has a merit that it can be formed, and the whole structure can be simplified and miniaturized.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration example of an optical angular velocity detector according to the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of the optical angular velocity detector shown in FIG.

FIG. 3 is a diagram showing a manufacturing process of a ring laser section and an optical waveguide which are integrally formed on a substrate.

FIG. 4 is a cross-sectional view of an epitaxial layer having a normal semiconductor laser structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Ring laser section 3 Optical waveguide 4 Light receiving diode 31 First clad layer of optical waveguide 32 Core 33 Second clad layer of optical waveguide 9

Claims (3)

[Claims] 1. A laser beam is propagated through a ring laser section in opposite directions, and a laser beam in each direction is received by a light receiving section to obtain a signal according to the beat of the laser beam in each direction. In an optical angular velocity detector designed to detect the angular velocity acting on the ring laser unit, the laser light propagating to the ring laser unit is sent to the light receiving unit through an optical waveguide that optically couples with the ring laser unit. A ring laser portion having a semiconductor laser structure is formed on a substrate, a first clad layer of an optical waveguide is formed on the ring laser portion and the substrate, and a first cladding layer is formed on the substrate. The core of the optical waveguide having a different optical refractive index from that of the clad layer is formed, and the second clad layer of the optical waveguide is further formed thereon. Characteristic optical angular velocity detector. 2. A laser beam is propagated to the ring laser section in opposite directions, and the laser beam in each direction is received by the light receiving section through an optical waveguide optically coupled to the ring laser section, and the laser beam in each direction is received. A method of manufacturing an optical angular velocity detector for detecting an angular velocity acting on a ring laser portion by obtaining a signal according to a beat of a laser beam, the laser epitaxial layer having a semiconductor laser structure provided on a substrate. To form a ring laser portion by etching, a step of forming a first cladding layer of the optical waveguide on the ring laser portion and the substrate, and a step of forming a first cladding layer on the first cladding layer. After forming the core layer of the optical waveguide having a different optical refractive index from the clad layer of No. 1, the core of the optical waveguide is formed by etching the core layer. A method of manufacturing an optical angular velocity detector, characterized in that a step of forming and a step of forming a second cladding layer of the optical waveguide from above are taken. 3. A first cladding layer formed on a substrate,
The method for manufacturing an optical angular velocity detector according to the above-mentioned item 2, wherein the light emitting layer in the ring laser portion and the core of the optical waveguide are formed so as to have a film thickness facing each other at the same height on the substrate.