Multiple cross switching in a two-mode semiconductor laser

A multiple cross switching phenomenon is observed in a two-mode semiconductor laser in an external cavity. Its physical origins are investigated. The changing temperature or injection current causes the variation of the refractive index and the length of the laser diode, leading to the shift of the modulated gain peaks of the anti-reflection-coated laser diode in the external cavity. Consequently, the two modes experience different gains periodically and the strong gain competition then leads to the multiple cross switching. © 1996 American Institute of Physics.