JPH02285691A - Integrated semiconductor light source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an integrated wavelength tunable light source made of a compound semiconductor that is applicable to the field of optical integrated circuits or optoelectronic integrated circuits.

[Conventional technology]

Conventionally, attempts have been made to convert the laser light wavelength to another wavelength by introducing laser light into a nonlinear optical crystal and using the nonlinear optical effect to generate optical parametric excitation.
electronics) J [Author: Amnon Yariv] [Publisher: Halt 5anders J
apan)] (3rd edition), P, 252-263
In addition, a light source for an analyzer using a combination of a YAG laser and a lithium niobate single crystal has been put into practical use.

FIG. 2 shows a schematic configuration diagram. Part A shows a laser oscillation part, and part B shows an optical parametric excitation part.

[Problems to be Solved by the Invention] However, the system configured by combining the plurality of individual elements described above has the following problems.

1. Since each element is modularized, it does not become a constituent element of an optoelectronic integrated circuit.

2. Since extremely high-quality single crystals are required, costs for crystal growth, crystal polishing, assembly, etc. are high.

3. It is also difficult to align the optical axis of the optical system.

4. Therefore, energy conversion efficiency is low.

An object of the present invention is to solve this problem and provide a device that can be integrated with a brainer.

[Means for Solving the Problems] In order to solve the problems described above, the present invention is characterized by comprising the following means.

1. The crystal for optical parametric excitation is a compound semiconductor crystal.

2. Use a semiconductor laser as a light source.

3. The compound semiconductor is formed on the same substrate as the semiconductor laser by evixaxial growth.

4. The optical parametric excitation section forms an optical waveguide and is optically coupled to the laser oscillation section optical waveguide.

5. The optical coupling is based on the same principle as an optical directional coupler.

[Example] An example of the present invention will be described below. The basic idea of the present invention is to use the laser light of a well-known semiconductor laser as a light source and optically couple it to optical waveguides made of nonlinear optical crystals arranged adjacently on both sides of a laser resonator. After generating optical parametric oscillation by using the three optical waveguides of the waveguide and the two optical waveguides, the wavelength-converted light is extracted from one or both of the end faces of the optical waveguides on both sides. At this time, the angular frequency W3 of the laser beam and the angular frequency W1 of the light induced in the two optical waveguides on both sides
and between W2, W s due to parametric excitation
" W + + W 2 is set so that the relationship holds. Wl and W2 are controlled by applying an appropriate voltage to the optical waveguide to vary the refractive index of the crystal by electro-optic effect. This makes it possible, for example, to vary W continuously while maintaining the above relational expression.

FIG. 1 is a schematic diagram of the structure of a device showing one embodiment of the present invention. (a) is a schematic cross-sectional view, and (b) is a schematic plan view.

Here, a method for manufacturing this structure will be described. First, a central laser oscillation part is formed. On an n-type GaAs substrate,
An n-type GaAs buffer layer 150 is deposited. Sequential n A
lx Ga+-x As (x=0.1) 102,
n-Ga As 103, P Alx Ga+-x A
s (x = 01) 104, P-GaAs 151
Then, by MOCVD, the layers are erectically grown and laminated.

Layer 102 is a laser oscillation active layer. Next, both sides are etched away leaving the laser resonator portion, and the surface of the buffer layer 150 is removed. Next, the surfaces other than the optical waveguide portions 119 and 120 on both sides of the laser resonator are coated with SiO□
Coat with a membrane. Next, a Zn Sx Se layer-x 107.111 as a cladding layer is placed on the 119.120 part.
is formed by selective epitaxial growth using the MOCVD method. Subsequently, ZnSe layers as optical waveguide layers 108 and 112 are similarly formed by selective epitaxial growth. In this way, the three optical waveguide layers 10
2.108.112 are formed adjacently on the same plane.

The conditions for the MOCVD evixial growth are as follows.

(1) Laser resonator partial raw material gas Nitrimethylgallium/trimethylaluminum, arsine Substrate temperature near 606-820℃ Pressure crab 700-790Torr Growth rate = 0
07-0.08 um/m1n (2) ZnSe optical waveguide part raw material gas: trimethyl zinc, hydrogen sulfide, hydrogen selenide Substrate temperature: 250'-350°C Pressure + 100 Torr or less Growth rate: 0.05-007 μm/min Next, electrode 1
05.109.113 is installed by vapor deposition method. A voltage is applied through each wiring 106.1.10.114. 1
06 is a power supply for driving the laser, and 110 and 114 are power supplies for adjusting the refractive index of each optical waveguide. Reflection surfaces 115 and 116 for forming an optical resonator are made completely flat by cleaving the crystal. Furthermore, the reflective surface 115 is (
l l O) Crystal plane. Also, n Ga As substrate 1
The 01 surface is a (110) crystal plane. For example, gold is deposited on the surface of the end face 117 on one side of the laser resonator to reflect almost 100% of the laser beam, so that the laser light is not directly emitted from the end face 117. Thereby, the wavelength-converted light 118 can be separated. That is, it can be used independently as a wavelength-converted light source.

The selection of the wavelength to be converted is determined by the optical waveguide layers 107.1 on both sides.
This is achieved by applying an electric field to 12 through electrodes 113 and 110. That is, it is set based on the two electric field strengths and the difference between the two electric field strengths. Furthermore, the conversion efficiency of the light amount is 119.120.12
1, that is, the resonator length. In this embodiment, trial and error is carried out to determine the length of several millimeters. Furthermore, the laser oscillation wavelength can be changed by varying the value of X in Ax Ga+-x As, and
It is also fully applicable to composition systems such as In As P system, Ga In P system, etc. As an example of the optical output, the semiconductor laser has a wavelength of 830 nm, a laser output of 50 mW, a wavelength variable range of 1130 to 530 nm, and an optical output of Ol to 1 mW.

In this embodiment, two optical waveguides 119 and 120 are arranged, but it is also possible to use only one of them. However, in the case of two trees, wavelength control accuracy and wavelength conversion efficiency are high.

[Effect of the invention] As mentioned above, the present invention has the following effects.

■ It is extremely compact and can be handled in the same way as conventional IC chips.

2. Planar integration is possible as a component of an optoelectronic integrated circuit.

3. Does not require a high-quality, large-sized non-linear optical crystal.

4. The thin film crystal for optical wavelength conversion can be ensured with high quality through MOCVD epitaxial growth, and high conversion efficiency can be obtained.

5. It is a useful wavelength tunable light source that can be coplanarly coupled to other types of optical waveguide devices using an optical waveguide.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view and a diagram schematically showing a planar structure of a light source according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing a typical conventional optical parametric excitation. 101 ・ 102 ・ 103 ・ 104 ・ 105 ・ 106 ・ 107. 108. 112 ・ ・ N-type Ga As substrate n Alx Ga+-x As (x=0.11n Ga
As P Alx Ga+-x As (x=0.ll Ohmic electrode lead wire Zn Sx Se+□ Ebiquixial layer Zn Se Ebiquixial optical waveguide layer 109 ・ 110 ・ ・ ・ ・ ・ ・ 113 ・ ・ ・ ・ ・ ・ l 4 ・ 15, l 7 ・ 18 ・ l 9. 150 ・ 151 ・ 201. 202 ・ 204 ・ 205. 206 ・ 116 ・ 120. 203 ・ 207 ・ Electrode film (Schottky barrier) Lead wire electrode film (Schottky barrier) Lead wire reflective surface (Cleavage plane) Gold evaporated thin film Wavelength converted light Optical resonator lid part n-type Ga As buffer layer P Ga As reflector Laser crystal lens Reflector Nonlinear optical single crystal or higher

Claims (2)

[Claims] (1) A semiconductor laser resonator and another optical waveguide are arranged on the same plane, and are arranged at a distance such that the two are optically coupled, and an electric field is applied to the surface of the other optical waveguide portion to the optical waveguide. 1. An integrated semiconductor light source characterized by having a structure in which a thin electrode film is arranged to impart (2) The integrated semiconductor light source according to claim 1, wherein the other optical waveguide is made of a II-VI group compound semiconductor epitaxial layer.