Patent ID: 8655192

Claim:
A polarization diversity optical system device, comprising: a polarization split unit having a first split part that splits a first coherent light into a first split light and a second split light whose polarization components are orthogonal to each other, and a second split part that splits a second coherent light into a third split light and a fourth split light whose polarization components are orthogonal to each other; and a light combining unit having a first combine part that combines the first split light with one of the third split light and the fourth split light, and a second combine part that combines the second split light with the other of the third split light and the fourth split light, wherein each of the first split part, the second split part of the polarization split unit, the first combine part and the second combine part of the light combining unit has a polarization split function, and the first split part, the second split part of the polarization split unit, the first combine part and the second combine part of the light combining unit are located at different positions from each other on one plane.