Generation of high speed, linear wavelength sweeps using sampled grating distributed Bragg reflector lasers

Abstract

-Wavelength-tunable sampled grating distributed Bragg reflector (SG-DBR) lasers are used for telecommunications applications in which the laser is set to a communication channel and changed infrequently. SG-DBR lasers can be tuned to any wavelength over a 50 nm tuning range with fast transition times using a set of three control currents. This paper demonstrates generation of fast linear wavelength ramps covering the entire tuning range of the laser. Continuous and linear wavelength sweeps are achieved by applying three time synchronized waveforms to the front mirror, back mirror, and phase sections of the laser. Continuous wavelength coverage is achieved by appending 50 separate mode-hop-free tuning segments.The wavelength stitching transitions require a maximum of 60 ns for amplitude, wavelength, and thermal settling time to allow the laser and drive electronics to equilibrate. Full band wavelength ramps with 100 kHz repetition rates have been demonstrated. An example FMCW LIDAR application of this fast wavelength ramp is given.Index Terms -Distributed Bragg reflector lasers, light detection and ranging.