Patent ID: 9450699
Filing Date: 2016-09-20
CPC Classification: H04J,H04Q

Claim Text:
1. An optical drop device, comprising: a clock extractor configured to extract a clock signal from a multi-channel optical signal that includes a plurality of optical signals having different optical frequencies; a pulse generator configured to generate a pulse signal that is synchronized with the clock signal; a modulator configured to perform phase modulation on the multi-channel optical signal using the clock signal, and a dispersion medium configured to generate a time division multiplexing optical signal by applying chromatic dispersion to the phase modulation multi-channel optical signal that is output from the modulator; an optical switch configured to drop an optical signal that exists in a time slot to which the pulse signal is applied, from the time division multiplexing optical signal; a control unit configured to generate a control signal that is used to control timing of a pulse signal that is applied to the optical switch, based on strength of the optical signal that is dropped by the optical switch; a first optical Fourier transform unit configured to transform the time division multiplexing optical signal from which the optical signal is dropped by the optical switch, into a frequency area optical signal; and a second optical Fourier transform unit configured to transform the optical signal that is dropped from the time division multiplexing optical signal by the optical switch, into a frequency area optical signal.