1.55 /spl mu/m high efficiency tapered DFB laser using UV 250 2-in technology process

We report on high external efficiency reduced far field divergence DFB laser emitting at 1.55 /spl mu/m. A high spatial resolution lithography is used to define the tapered section of the spot size converter integrated in the device. Thanks to suitable UV-250 contact lithography process, sub-micron patterns, 2-inch homogeneity, and run to run reproducibility is simultaneously achieved. 15/spl deg//spl times/15/spl deg/ front facet divergence is obtained allowing 3.6 dB coupling loss to an AR coated end-cleaved standard optical fibre. Threshold current as low as 11 mA and external efficiency up to 0.42 W/A at 25/spl deg/C have been measured on 500 /spl mu/m long lasers.