Patent ID: 7725040

Claim:
An optical apparatus, comprising: a receiving device configured to receive a wavelength division multiplexed (WDM) light multiplexed by a plurality of optical signals with different wavelengths; a planarizing device configured to planarize one of the plurality of optical signals of the WDM light and output a planarized light; a modulation device configured to modulate the planarized light into a modulated optical signal; and a transmitting device configured to transmit a WDM light including the modulated optical signal, wherein the planarizing device includes an optical resonator configured to input and resonate the one of the plurality of optical signals, the optical resonator having a peak at a wavelength of the one of the plurality of optical signals, wherein a laser diode supplies a light which has a peak at substantially the same wavelength with the peak of the optical resonator, and wherein the optical resonator is a plurality of optical resonators configured to input and resonate several optical signals of the plurality of optical signals of the WDM light and the planarizing device includes a multiplexer configured to multiplex several lights output from the plurality of optical resonators and output the light to the laser diode.