Patent ID: 6961169

Claim:
A light-controlled light modulator comprising: first optical branching means for branching first input light; optical branching-delaying means for branching and delaying second input light; a first optical combiner/splitter for combining a first branched part of the first input light with a first branched part of the second input light, and for distributing them to a plurality of ports; phase modulators, which are connected to the plurality of ports, including media that vary their refractive indices in response to the light intensity of the first input light; a second optical combiner/splitter for combining outputs from said phase modulators and for branching them to a plurality of parts, and for coupling them with a second branched part of the first input light and a second branched part of the second input light; and said optical branching-delaying means being connected to said second optical combiner and including a third optical combiner connected to a plurality of optical branching-delaying circuits which are different in length, wherein when the wavelength of the signal light equals the wavelength of the light to be converted, the wavelength conversion becomes possible without mixing noise into the wavelength-converted light output.