Reduction of mode partition noise in a multiwavelength semiconductor laser through hybrid modelocking

Summary form only given. The longitudinal modes of a multimode laser diode suffer from intensity fluctuations that, when coupled with spectral filtering, result in mode partition noise (MPN). We have significantly decreased the MPN in a modelocked, multiwavelength semiconductor laser. A gain-guided GaAs-AlGaAs semiconductor optical amplifier (SOA) is inserted in an external cavity which incorporates a spectrometer and binary amplitude spatial filter to define individual wavelength channels. Our method exploits the saturable nonlinearity in a multiple-quantum-well (MQW) saturable absorber, along with high speed gain modulation, to establish hybrid modelocking in the external cavity semiconductor diode laser. The result is an error-free optical pulse train in each of the wavelength channels generated by the multiwavelength laser.