Optical signal inverter using injection locking of coupled semiconductor lasers

We propose and demonstrate a unique optical signal inverter using injection locking in coupled semiconductor lasers with a narrow-band Fabry-Perot (F-P) etalon. In this method, one laser diode is operated as a master laser to control the injection locking and the other is operated as a slave laser. By setting of the F-P etalon inside the coupled cavity, the locking and unlocking states can be allocated to the lon and high levels for the output power respectively. Under direct modulation of the master laser, the inverted light signal is available from the output port. This optical inverter can be operated at an output power of similar to 7 mW.