Anomalous interaction of spectral modes in a semiconductor laser

An investigation was made of the nonlinear interaction between spectral modes in an injection laser with external resonator which had two resonant feedback channels. These channels were provided by diffraction gratings used as tunable selective elements. The emission occurred at two wavelengths and, in addition to the usual competition due to the interaction of the fields via the population inversion, there was an interaction which depended on the magnitude and sign of the spectral separation between the modes. When this separation was 1 nm or less the long-wavelength mode was emitted preferentially. The anomalous competition was attributed to the parametric interaction between the modes.