METHOD FOR WAVELENGTH-DEPENDENT COMPENSATION IN A VARIABLE OPTICAL ATTENUATOR

摘要

The present invention provides a wavelength dependent compensation methodin a variable optical attenuator which cam precisely set the amount ofattenuation withina wide range of wavelengths, and to provide superior operability. An opticalsignal20a is emitted from a white light source 20 incident on a monochromator 21,and undercontrol of a CPU 24, only an optical signal 20b of a specific wavelength isextracted andis made incident on a variable optical attenuator 22; in optical attenuator 22undercontrol of a CPU 24, optical signal 20b is attenuated; the power of attenuatedopticalsignal 20c is measured by power measurer 23 under control of a CPU 24,producingcompensating data; and using the pulse number corresponding to the rotationangle ofthe motor which activates the variable optical attenuator 22 according to thiscompensating data, the position of variable optical attenuator 22 iscompensated toattain the desired amount of attenuation.