Widely tunable electroabsorption-modulated sampled-grating DBR laser transmitter

We report on a widely tunable transmitter based on a sampled-grating distributed Bragg reflector (SG-DBR) laser monolithically integrated with a semiconductor optical amplifier (SOA) and an electroabsorption (EA) modulator. Modulated time-averaged powers in excess of 5 dBm, RF extinction ratios >10 dB, and error-free transmission at 2.5 Gb/s for 350 km of standard single-mode fiber have been demonstrated across a 40-nm tuning range. In CW mode of operation, the module meets all long-haul system requirements for externally modulated laser sources: stability, power (>10 mW), RIN (<-140 dB/Hz), and linewidth (<2 MHz) over 90 50-GHz spaced ITU channels. Implementation of wavelength, power, and mode control in module firmware ensures long-term stability for system deployment. Systematic investigations of accelerated aging performed on laser tuning and gain sections showed excellent wavelength stability and reliability with median times to failure of >100 yr for output wavelength stability and power across all channels.