WAVELENGTH-TUNABLE INGAASP-INP MULTIPLE-LAMBDA 4-SHIFTED DISTRIBUTED-FEEDBACK LASER/

A wavelength-tunable InGaAsP/InP multiple-lambda/4-shifted distributed feedback (MQS-DFB) laser was demonstrated for the first time. A DFB l aser with three lambda/4-shifts and five electrodes was fabricated and its fundamental characteristics, such as tunability, spectral linewid th and FM response, were investigated. The stable single mode operatio n with an excellent SMSR of more than 40 dB was confirmed. Continuous wavelength tuning under constant output power mode was obtained with a range of 1.7 nm. Minimum spectral linewidth was 3 MHz at an output po wer of 20 mW. Flat FM response up to 4 GHz with an efficiency of about 0.65 GHz/mA was also obtained.