| 摘要 |
PROBLEM TO BE SOLVED: To obtain a clock signal extracting device which operates stably and is small-sized. SOLUTION: Electric signals V1 to V4 of (f), Δf, f-Δf, and f+Δf (GHz) are generated, a light signal P1 of 2f is modulated with the electric signal V4 to generate a light signal P5 of f-Δf, which is photoelectrically converted to generate an electric signal V7; and the phase of the electric signal (frequency- divided clock signal) V1 is controlled so that the phase difference between the signals V7 and V3 is eliminated. An electric circuit which operates up to a frequency a half as high as the frequency of the light signal P1 can extract the frequency-divided clock signal V1. |
