Patent attributes
A clock extracting apparatus is provided. In the clock apparatus, two frequency components are made to have an equal magnitude by adjusting a temperature and current applied to an FP LD, and a clock signal is extracted by beating the two frequency components having the equal magnitude. The clock extracting apparatus includes: a circulator for changing a direction of an inputted optical signal; an adjuster for adjusting a characteristic and wavelength of a spectrum; and a clock extractor for selecting two frequency components having different magnitudes on the spectrum of the inputted optical signal, receiving an adjusted signals in which magnitudes of the two frequency components are made equal by the adjuster, making the two frequency components have an equal magnitude, and extracting a clock signal by beating the two frequency components having the equal magnitude.