Temporal wavelength multiplexing of quantum cascade laser

A quantum cascade (QC) laser is presented that is both temporally and wavelength multiplexed, i.e. it emits two widely different wavelengths at two alternate time slots. A bidirectional and multi-wavelength QC laser source that emits at 10.8 m wavelength for a positive polarity current and 8.6 m for a negative polarity current was used. A diode based adder circuit was designed to drive the QC laser such that it added two opposite polarity current pulses with a variable time delay. Application of two polarity 100 ns pulse width current pulses at 80 kHz with time delays of 0.5 to 2.5 s resulted in a versatile time and wavelength multiplexed QC laser.