Design and fabrication of high performance widely tunable sampled grating DBR laser

We have demonstrated a high-performance sampled grating distributed bragg reflector laser by using a planar buried heterostructure for the first time, where active and passive regions were butt-coupled by using ME followed by an adequate amount (125 nm thick) of selective wet etching that provided excellent uniformity throughout a quarter of a 2-inch wafer. The measured average coupling efficiency was 96 +/- 1.7% per facet. The maximum output power of the fabricated device was 20 mW at 200 mA under CW operation at 25 degreesC. Average threshold current and voltage were approximately 12 mA and 0.8 V. We obtained a total tuning range of 57 nm and a side mode suppression ratio of more than 35 dB in the whole tuning range. Optical output power variation was less than 5 dB, which is similar to4 dB smaller than that when using a RWG structure.