Narrow linewidth 1560 nm InGaAsP split-contact corrugated ridge waveguide DFB lasers

We demonstrate a split-contact corrugated ridge waveguide InGaAsP distributed feedback laser at 1560 nm. The laser cavity has been defined with uniform third-order gratings etched along the sidewalls of the ridge waveguide. The gratings were fabricated using a standard I-line stepper lithography technique along with an inductively coupled reactive ion-etching process. Stable single-mode operation has been achieved with side-mode suppression ratios ≥50  dB, output powers ≥7  mW, a wavelength tuning range ≥2.3  nm, and narrow linewidths (≤140  kHz) for different biasing conditions, with a minimum of 70 kHz. The effect of p-contact partition on device performance is also studied.