Optical filtering to reduce chirping influence in LD wavelength conversion

The use of an optical filter to reduce chirping influence in LD wavelength conversion is demonstrated. A part of broadened spectrum of wavelength-converted light is eliminated by a narrow-band optical filter, and sensitivity degradation due to frequency chirping is reduced as a result. In an experiment using a fiber Fabry-Perot filter, the sensitivity was improved by about 1.5 dB in 1.55-μm transmissions with normal dispersion fibers when an LD converter was biased at two times the threshold current.