Patent ID: 7274875

Claim:
An optical channel power equalizer for equalizing per-channel power levels of a multi-channel optical signal, in which a plurality of channels are multiplexed and amplified, the optical channel power equalizer comprising: an optical spectrum measurement unit that extracts a portion of the amplified optical signal and measures the per-channel power levels of the extracted optical signal, the optical spectrum measurement unit including an optical input unit that adjusts a spot size of the input optical signal; a controller that compares the measured power levels with a predetermined reference value, and determines to output the degrees of attenuation per channel based on differences between the measured per-channel power levels and the reference value; and a per-channel optical attenuation unit that attenuates the per-channel power levels of a plurality of input optical signals based on the degrees of attenuation and outputs the attenuated optical signals as the plurality of channels, wherein the optical spectrum measurement unit includes: a lens that collimates in parallel a light that is dispersed and input by the optical input unit; an optical wavelength separator that separates a light passing through the lens in a wavelength unit; a phase delayer that delays phases to change polarization states of the per-wavelength separated lights; a plane mirror that reflects the lights passing through the phase delayer; and an optical detection unit that receives to measure the power levels of the lights being reflected by the plane mirror and passing through the phase delayer, the optical wavelength separator, and the lens, sequentially.