DESIGN AND FABRICATION OF WIDELY TUNABLE SAMPLED GRATING DFB LASER DIODE INTEGRATED WITH SAMPLED GRATING DISTRIBUTED BRAGG REFLECTOR

A sampled grating distributed feedback (SGDFB) laser diode integrated with a sampled grating distributed Bragg reflector (SGDBR) is designed, fabricated, and characterized. In the proposed laser diode, only two tuning currents, one into the longitudinal mode tuning electrode and the other into the SGDBR tuning electrode, are required, which provides an easier tuning mechanism. A split-step time-domain modeling is used to simulate the designed tunable laser diode and it is shown that a tuning range of about 27 nm with the side mode suppression ratio (SMSR) larger than 50 dB for the particular device. The designed SGDFB-SGDBR laser diode is fabricated using buttcoupling interface between the active and passive waveguides in an InGaAsP/InP platform. The tuning range of the fabricated device is about 20 nm with the SMSR of about 30 dB. The fiber-coupled output power is about 8mW for the tuned lasing modes. The measured results exhibit the proof-of-concept of the SGDFB-SGDBR laser diode despite the room for improvement in the design and fabrication processes. (C) 2016 Wiley Periodicals, Inc.