| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical performance monitor which is capable of accurately measuring an optical signal wavelength being transmitted, optical power of each optical signal, and an OSNR.SOLUTION: The optical performance monitor includes: a waveguide type spectrometer 2; a polarization splitter 6 which splits light emitted from the waveguide type spectrometer 2 and transmitted through a first lens 3, into X-polarized light and Y-polarized light and emits them to a second lens 7; a variable retarder 4 which is provided between the waveguide type spectrometer 2 and the polarization splitter 6 and adjusts a phase difference between a polarization component in its one birefringence axis direction and a polarization component in the other birefringence axis direction orthogonal to the one birefringence axis direction to adjust an optical power ratio of the X-polarized light and the Y-polarized light; a half wave plate 8 which spatially rotates, at 90°, only one of the X-polarized light and the Y-polarized light which are emitted from the second lens 7; an optical phase modulator 9 which reflects one polarized light from the half wave plate 8 and the other polarized light from the second lens 7, to the second lens 7; and a light receiving element array 10 which detects interference fringes between both of polarized light beams condensed by the second lens 7. |
