| 摘要 |
PROBLEM TO BE SOLVED: To suppress the variance of the signal level of a photodetector which converts an optical signal to an electric signal regardless of the difference of transmission loss between two separated polarized light or the variance of an intensity ratio. SOLUTION: An optical modulator 1 is so constituted that one of two separated polarized light whose planes of polarization are perpendicular to each other is transmitted through a half-wave plate 24, a Farady rotator 25, and an optical attenuator 51 before the incidence of these separated polarized light on reflection optical modulators 21 and 22 and the optical attenuator 51 is continuously displaced perpendicularly to the optical path. This optical modulator 1 is mounted on a reception equipment. |
