| 摘要 |
PROBLEM TO BE SOLVED: To avoid the problem of crosstalk between transmission light and reception light in the case of adjacently installing a polarized light separating plane and a luminous flux division plane by providing a specified polarized light separating plane and a specified laser beam source in a transmission/reception part. SOLUTION: An emitted luminous flux from a semiconductor laser beam source 32 is made incident on the incident surface 73 of the rectangular prism 70 of the transmission/ reception part 30. The emitted luminous flux of the semiconductor laser beam source 32 is provided with linear or elliptic intensity distribution and a θparallel direction (short axis direction) length θH orthogonally crossed with each other on an optical axis orthogonal cross section is shorter than a θ vertical direction (long axis direction) length θV. Then, the θ parallel direction θH is turned around an optical axis 32X and the position is determined so as to be almost parallel to the optical axis from the polarized light separating plane PBS to the luminous flux division plane BS. Also, for the polarized light separating plane PBS, various conditions are set so as to be a plane (P polarized light transmission S polarized light reflection plane) for transmitting a linearly polarized luminous flux from the semiconductor laser beam source 32 and reflecting the linearly polarized luminous flux whose phase is made different for 90 deg. from the linearly polarized luminous flux. |
