To realize a fast operating optical gate circuit.

A polarization mode dispersion device (PMD) 10 separates a linear polarization signal light pulse 11 into a TE component and a TM component each having an equal power, and outputs them with a time difference of about 5 ps. A control light pulse 12 is time-adjusted by an optical delay line 13, and thereafter it is made incident to a 3 dB optical coupler 14. The optical coupler 14 multiplexes the control light pulse from the optical delay line 12 and output light of the PDM 10 and makes them incident to an electric absorption type optical waveguide 16 biased in reverse. A delay time of the optical delay line 13 is set so that the control light is made incident to the electric absorption type optical waveguide 16 at the same time as or immediately before a trailing pulse outputted from the PMD 10. The electric absorption type optical waveguide 16 absorbs the control light and modulates it by phase. The PMD 20 and a phase compensation circuit 22 offset the time shift caused by the PMD 10. A polarizer 24 extracts a polarization direction component when the control light pulse exists from an output light of the phase compensation circuit 22, and an optical band-pass filter 26 extracts component of a wavelength λs from the output light of the polarizer 24.