Patent ID: 6236488
Filing Date: 2001-05-22
Classification: G01J,G02F,H04J

Abstract:
An optical pulse position detecting circuit comprising:an optical pulse string input terminal receiving an optical pulse string with a determined repetitive cycle;an oscillator for outputting an electric clock signal with a same frequency as the repetitive cycle of the optical pulse string;a phase shifter for receiving the electric clock signal output from the oscillator, shifting a phase of the electric clock signal, and outputting a shifted electric clock signal;an optical modulator for receiving the shifted electric clock signal output from the phase shifter and the optical pulse string received by the optical pulse string input terminal, modulating the optical pulse string based on the electric clock signal and outputting a modulated optical signal;an optical detector for converting the modulated optical signal output from the optical modulator to an electric signal and outputting the electric signal;a phase controlling circuit for receiving the electric signal output from the optical detector and controlling a phase shift amount of the phase shifter to maximize an output from the optical detector; anda phase shift amount output terminal for outputting the phase shift amount of the phase shifter.