Optical semiconductor device and manufacturing method therefor
A manufacturing method for an optical semiconductor device, including disposing a semiconductor element that has a polarization dependent gain or polarization dependent loss between optical waveguide modes differing in the direction of polarization, positioning a lens at one end face side of the semiconductor element based on an optical coupling loss between the lens and the semiconductor element, and repositioning the lens based on the polarization dependent gain or the polarization dependent loss of the semiconductor element.
1. An optical semiconductor device, comprising:
a semiconductor element that provides different spot sizes on an element end face for optical waveguide modes including a first optical waveguide mode and a second optical waveguide mode, the first optical waveguide mode having a first direction of polarization and the second optical waveguide mode having a second direction of polarization which is orthogonal to the first direction of polarization; and
a lens positioned at one end face side of the semiconductor element,
wherein a spot size at a beam waist position of the lens is smaller than spot sizes in both of the first optical waveguide mode and the second optical waveguide mode, and
wherein the lens is provided at a position where a polarization dependent gain or a polarization dependent loss of the semiconductor element is compensated by an inter-polarization difference in optical coupling loss between the semiconductor element and an optical fiber to be coupled to the lens.
2. The optical semiconductor device according to claim 1 , wherein the first optical waveguide mode is a transverse electric mode and the second optical waveguide mode is a transverse magnetic mode.
3. The optical semiconductor device according to claim 1 , further comprising:
another lens positioned at the other end face side of the semiconductor element.
4. The optical semiconductor device according to claim 3 , wherein a spot size at a beam waist position of the another lens is smaller than the spot sizes in both of the first optical waveguide mode and the second optical waveguide.
5. The optical semiconductor device according to claim 4 , wherein the first optical waveguide mode is a transverse electric mode and the second optical waveguide mode is a transverse magnetic.
6. The optical semiconductor device according to claim 1 , wherein a position of the beam waist position of the lens is shifted from one end face of the semiconductor element to an optical axis direction.