AWavelength conversion apparatus has an optical ampli? er, a Wavelength converter, and
an optical coupler coupled to form an optical ring resonator. The optical ampli? er supplies
pump light. The Wavelength converter generates converted light, either from the pump light
alone or by interaction between the pump light and signal light supplied from a signal
source. The optical coupler extracts the converted light. The optical ring resonator preferably
includes a tun able optical bandpass? lter that de? nes the Wavelength of the pump light …