Patent ID: 7580640

Claim:
An apparatus for extracting an optical clock signal, the apparatus comprising: a reflector rotating frequency components of an input optical signal by a predetermined angle and then reflecting them; a bi-directional amplifier amplifying frequency components of the input optical signal before transmitting them to the reflector and amplifying frequency components reflected from the reflector; a polarization beam splitter splitting a predetermined polarization component from the optical input signal through an input terminal; a Fabry-Perot filter selecting frequency components for clock signal extraction from the predetermined polarization component received from the polarization beam splitter, transmitting the selected frequency components to the bi-directional amplifier, and removing noise from the frequency components that have been reflected from the reflector and amplified by the bi-directional amplifier; and a photodetector receiving the noise-removed frequency components from the Fabry-Perot filter and obtaining a beat frequency component from the noise-removed frequency components to extract an optical clock signal.