Optical semiconductor device and optical semiconductor integrated circuit

Abstract

An integrated optical waveguide has first, second, and third optical waveguiding regions. The second optical waveguiding region has a refractive index different from that of the first optical waveguiding region. The second optical waveguiding region has an interface surface with the first optical waveguiding region that is inclined with respect to the waveguide direction of the first optical waveguiding region. The third optical waveguiding region has an interface surface with the second optical waveguiding region that is disposed such that a refraction direction through the interface surface is in line with the waveguide direction.

Description

[0001] This application is a divisional application of a patent application with an application date of March 30, 2004, an application number of 200480000980.X (PCT / JP2004 / 004517), and an invention title of "Optical Semiconductor Element and Optical Semiconductor Integrated Circuit". technical field [0002] The present invention relates to optical semiconductor elements such as semiconductor lasers, optical waveguides, and other optical devices, and optical semiconductor integrated circuits, and more particularly to optical semiconductor elements in which materials having different refractive indices and temperature dependencies of refractive indices are combined on a semiconductor substrate and optical semiconductor integrated circuits. Background technique [0003] The vibration wavelength of semiconductor lasers changes with ambient temperature and element temperature. For example, as published by K.Sakai, "1.5μm range InGaAsP / InP distributed feedback lasers," IEEEJ.Quan...

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Problems solved by technology

[0025] However, when a semiconductor optical waveguide is coupled to an optical waveguide made of a material having a different refractive index from the semiconductor optical waveguide, the degree of freedom in waveguide design is limited due to reflection at the bonding interface corresponding to the difference in refractive index.

[0026] where by using the Brewster angle θ B , the reflection between waveguides with different refractive indices can be reduced, but using the Brewster angle θ B If the light is refracted at the boundary surface between the waveguides, there is a problem that the waveguide direction becomes not a straight line.

[0027] In addition, Brewster's angle θ is used to reduce reflection between waveguides with different refractive indices. B If this is the case, it becomes difficult to fabricate a buried semiconductor waveguide along a specific crystal direction, and there is a problem that a buried semiconductor waveguide cannot be fabricated with high reliability.

[0028] Furthermore, if Brewster's angle θ is used to reduce reflection between waveguides with different refractive indices, B If this is the case, it is difficult to arrange the semiconductor waveguide perpendicular to the cleavage plane, and there is a problem that the cleavage plane cannot be used as a reflection surface of a semiconductor laser or the like.

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