Patent ID: 7835643

Claim:
An optical waveform measuring apparatus comprising: a sampling light outputting unit which outputs a sampling light pulse to sample a light under measurement; a sampling result outputting unit which develops a nonlinear optical effect stemming from said light under measurement and said sampling light pulse from said sampling light outputting unit to output a light corresponding to a result of the sampling of said light under measurement; and a polarization state control unit which carries out control of polarization states of the light under measurement and the sampling light pulse, which are to be inputted to the sampling result outputting unit, based on a power level of said light from said sampling result outputting unit, wherein said sampling result outputting unit comprises a directional coupler which directionally couples the light under measurement and the sampling light pulse, each having undergone the control of the polarization states thereof carried out by said polarization state control unit, respectively, and outputs a multiplexed light, a nonlinear medium which develops a nonlinear optical effect stemming from said multiplexed light, and a linear polarization component extracting unit which extracts a linear polarization component of said light under measurement, whose polarization state undergoes a variation due to said nonlinear optical effect developing in said nonlinear medium, for the waveform measurement, and said polarization state control unit carries out control over the polarization state of the light under measurement so that a polarization state of said light under measurement to be inputted to said nonlinear medium becomes a linear polarization substantially perpendicular to a direction of said linear polarization component to be extracted in said linear polarization component extracting unit, and further carries out control of the polarization state of the sampling light pulse so that a polarization state of said sampling light pulse to be inputted to said nonlinear medium becomes a linear polarization having an angle of 40 to 50 degrees with respect to a direction of a linear polarization to be controlled with respect to said light under measurement, wherein said sampling result outputting unit further comprises a temperature adjusting unit that stabilizes the temperature of the nonlinear medium to reduce an influence of an external temperature variation on the nonlinear medium.