Wavelength conversion using two pump four-wave mixing in a double-moded distributed-feedback laser

Although it has been proposed that the use of two pumps at different wavelengths can enhance the conversion efficiency for large wavelength shifts, little experimental work has been performed to demonstrate this enhancement. Previous experiments for two pump four-wave mixing have used a semiconductor optical amplifier as the mixing media with two external pumps and an external probe injected into the amplifier waveguide. In this paper, we propose a much simpler geometry using a laser with two simultaneous lasing modes. The two modes of the laser serve as dual pumps already in the mixing media. All that is needed is an external probe signal to be injected into the cavity. In our measurements, we use a DFB laser which has two stable modes of nearly equal magnitude several nanometers apart. We take advantage of the double lasing modes to perform the first detailed study of the conversion efficiency spectra of two pump four-wave mixing.