CN-122003789-A - Method for manufacturing wavelength variable laser element

CN122003789ACN 122003789 ACN122003789 ACN 122003789ACN-122003789-A

Abstract

A linear waveguide layer (22), a coupling layer (21), and a ring-shaped waveguide layer (23) are continuously formed over a semiconductor substrate (9). The annular waveguide layer (23) and the coupling layer (21) are etched to form an annular waveguide (8). The linear waveguide layer (22) is anisotropically wet etched to form a linear waveguide (7). The annular waveguide (8) and the linear waveguide (7) are optically coupled via a coupling layer (21) to form an annular resonator filter (5). When anisotropic wet etching is performed on the linear waveguide layer (22), the linear waveguide layer (22) below the annular waveguide (8) is removed in the region not covered by the linear pattern (25) using a chemical solution having selectivity in the direction in which the linear pattern (25) extends with respect to the linear waveguide layer (22).

Inventors

Nagano Ryusuke
Liu Lechong
SHINICHI KANEKO

Assignees

三菱电机株式会社

Dates

Publication Date: 20260508
Application Date: 20231013

Claims (5)

1. A method for manufacturing a wavelength variable laser element, wherein a gain section, a phase adjustment section, a diffraction grating, and a ring resonator filter optically coupled to the diffraction grating are disposed in a laser resonator, characterized by comprising the steps of: a step of continuously forming a linear waveguide layer, a coupling layer, and a ring-shaped waveguide layer over a semiconductor substrate; a step of forming a ring waveguide by etching the ring waveguide layer and the coupling layer using the circular pattern as a mask, and A step of forming a linear waveguide by anisotropically wet etching the linear waveguide layer using a linear pattern overlapping a part of the annular waveguide as a mask, The annular waveguide and the linear waveguide are optically coupled via the coupling layer to form the annular resonator filter, When anisotropic wet etching is performed on the linear waveguide layer, the linear waveguide layer below the annular waveguide is removed in a region not covered by the linear pattern using a chemical solution having selectivity in a direction in which the linear pattern extends with respect to the linear waveguide layer.
2. The method of manufacturing a wavelength variable laser device according to claim 1, wherein, The straight waveguide layer, the coupling layer and the annular waveguide layer are of a sphalerite type structure, The straight line pattern extends along the [0-11] direction.
3. The method of manufacturing a wavelength variable laser device according to claim 2, wherein, The linear waveguide layer is AlGaInAs, A mixed solution of tartaric acid and hydrogen peroxide water was used as the liquid medicine.
4. The method for manufacturing a wavelength variable laser device according to any one of claims 1 to 3, wherein, After the linear waveguide is formed with a width wider than a target width, the linear waveguide is patterned to the target width.
5. The method for manufacturing a wavelength variable laser device according to any one of claims 1 to 3, wherein, After the linear waveguide and the annular waveguide are formed with widths wider than a target width, respectively, the linear waveguide and the annular waveguide are patterned to the target widths, respectively.

Description

Method for manufacturing wavelength variable laser element Technical Field The present disclosure relates to a method of manufacturing a wavelength variable laser element. Background There is proposed a wavelength variable laser element in which a gain section, a phase adjustment section, a diffraction grating, and a ring resonator filter optically coupled to the diffraction grating are arranged in a laser resonator (for example, refer to patent document 1). The ring resonator filter has two linear waveguides and a ring waveguide formed over and optically coupled to the two linear waveguides. Patent document 1 Japanese patent application laid-open No. 2008-516283 In a conventional method for manufacturing a wavelength variable laser device, a linear waveguide is formed by etching a linear waveguide layer, and then the linear waveguide is buried in a semiconductor layer. The annular waveguide is formed by forming an annular layer over the semiconductor layer and etching. However, there is a problem in that the surface of the semiconductor layer bulges above the linear waveguide, and thus a step is generated in the annular waveguide formed thereon, resulting in an increase in the waveguide loss. Disclosure of Invention The present disclosure has been made to solve the above-described problems, and an object thereof is to provide a method for manufacturing a wavelength variable laser element capable of reducing the waveguide loss. The method for manufacturing a wavelength variable laser element is characterized by comprising a step of continuously forming a linear waveguide layer, a coupling layer, and a ring waveguide layer on a semiconductor substrate, a step of etching the ring waveguide layer and the coupling layer using a circular pattern as a mask, and a step of anisotropically wet etching the linear waveguide layer using a linear pattern overlapping a part of the ring waveguide as a mask, wherein the ring waveguide and the linear waveguide are optically coupled via the coupling layer to form the ring resonator filter, and wherein the linear waveguide layer is removed from a region below the ring waveguide layer using a chemical solution having selectivity in a direction in which the linear pattern extends with respect to the linear waveguide layer when anisotropically wet etching the linear waveguide layer. In the present disclosure, after a linear waveguide layer, a coupling layer, and a ring-shaped waveguide layer are continuously formed over a semiconductor substrate, the ring-shaped waveguide layer and the coupling layer are etched to form a ring-shaped waveguide. Since there is no step of embedding the linear waveguide with the semiconductor layer as in the conventional technique, no step is generated in the annular waveguide. As a result, the waveguide loss can be reduced. Drawings Fig. 1 is a perspective view showing a wavelength variable laser device according to embodiment 1. Fig. 2 is a cross-sectional view of the gain section along A-A ́ of fig. 1. Fig. 3 is a cross-sectional view of the diffraction grating along B-B ́ of fig. 1. Fig. 4 is a cross-sectional view of the ring resonator filter along C-C ́ of fig. 1. Fig. 5 is a cross-sectional view of the amplifier along D-D ́ of fig. 1. Fig. 6 is a cross-sectional view showing a method for manufacturing the wavelength variable laser device according to embodiment 1. Fig. 7 is a plan view showing a method for manufacturing a wavelength variable laser device according to embodiment 1. Fig. 8 is a cross-sectional view showing a method for manufacturing the wavelength variable laser device according to embodiment 1. Fig. 9 is a cross-sectional view showing a method for manufacturing a wavelength variable laser device according to embodiment 1. Fig. 10 is a plan view showing a method for manufacturing a wavelength variable laser device according to embodiment 1. Fig. 11 is a cross-sectional view showing a method for manufacturing a wavelength variable laser device according to embodiment 1. Fig. 12 is a cross-sectional view showing a method for manufacturing the wavelength variable laser device according to embodiment 1. Fig. 13 is a plan view showing a method for manufacturing a wavelength variable laser device according to embodiment 1. Fig. 14 is a cross-sectional view showing a method for manufacturing a wavelength variable laser device according to embodiment 1. Fig. 15 is a cross-sectional view showing a method for manufacturing the wavelength variable laser device according to embodiment 1. Fig. 16 is a plan view showing a method for manufacturing a wavelength variable laser device according to embodiment 2. Fig. 17 is a cross-sectional view showing a method for manufacturing a wavelength variable laser device according to embodiment 2. Fig. 18 is a cross-sectional view showing a method for manufacturing the wavelength variable laser device according to embodiment 2. Fig. 19 is a plan view showing a method for manufacturing a wavelength varia