Experimental demonstration of amplified feedback DFB laser based on the reconstruction equivalent chirp technique

An amplified feedback DFB laser with extended modulation bandwidth is experimentally demonstrated in this paper. All the three sections of laser cavity, including DFB section, phase section and amplified feedback section, have the same active layer, which can avoid the butt-joint re-growth process. The gratings in both DFB section and amplified feedback section are fabricated by the Reconstruction Equivalent Chirp technique, which can significantly decrease the difficulties in realizing precise grating structure. An enhanced -3 dB bandwidth of 19 GHz is realized by means of a normal low-frequency wafer. 16-QAM signals with the rate of 30 MSymbol/s and the center frequency of 15 GHz are transmitted via 10 km radio-over-fiber link employing the as-fabricated directly modulated DFB laser, and the average error vector magnitude of the whole link is 4.38%.