Patent ID: 7660536

Claim:
An optical modulating circuit comprising: a first light source which generates as a first single wavelength signal continuous light having a wavelength of a carrier wave as a first wavelength; a second light source which generates as a second single wavelength signal continuous light having a wavelength of a carrier wave as a second wavelength different from said first wavelength; an optical switch to which is input a transmission electric signal having information “0” or “1” as a switching signal, said first single wavelength signal as a first switch input signal and said second single wavelength signal as a second switch input signal and which selects said first single wavelength signal as a switch output signal when said information is “0”, selects said second single wavelength signal as a switch output signal when said information is “1”, and outputs the selected switch output signal as an input optical signal; an optical modulator which generates, from said input optical signal, an optical pulse signal obtained by arranging optical pulses having any one of said first wavelength and said second wavelength as a wavelength of a carrier wave at constant time intervals; and a delaying unit which delays the optical pulse having said first wavelength as the wavelength of the carrier wave and an optical pulse having said second wavelength as the wavelength of the carrier wave by different delay times to obtain a pulse position modulating signal.