Novel tunable DFB laser with separated high coupling coefficient gratings

A novel continuously tunable DFB laser is proposed that has separated high coupling coefficient gratings with simple current tuning. Deep corrugations designed to realize a high coupling coefficient are fabricated by using dry etching followed by shallow wet chemical etching and slow speed re-growth. A large stop-band width achieved by using a grating with a coupling coefficient as high as 200 cm-1 provides a continuous tuning wavelength range of 2.1 nm