A novel sampling Bragg grating for DFB laser

Based on reconstruction equivalent chirp (REC) technology, we propose a special structure for distributed feed-back (DFB) lasers realized by changing the duty cycle of one side in sampling Bragg grating, thus the equivalent apodization is introduced in this side, resulting into the magnitude of the equivalent index modulation is varied and smaller than the other side. As a conventional equivalent π phase-shift sampling Bragg grating (SBG), this proposed structure also introduces an equivalent π phase-shift into both its ±1 storder channel. Combined with the conventional equivalent π phase-shift, the sampling technique can be used to design and fabricate Semiconductor or fiber lasers conveniently.