Narrow Linewidth Semiconductor Laser Based on Anti-Symmetric Bragg Grating

We present a new configuration of narrow linewidth semiconductor lasers (NLSLs) based on a novel narrow-band reflector (NBR) with π phase-shifted anti-symmetric Bragg grating (π-ASBG). Based on this configuration, two specific laser structures are theoretically analyzed. The effective length of Bragg grating is highly increased due to the double hybrid-mode resonances between the fundamental transverse electric (TE0) mode and first-order transverse electric (TE1) mode in the π-ASBG with the aid of a uniform grating reflector. The narrowest linewidth of ∼2.4 kHz is obtained of the proposed NLSLs, which is much lower than the traditional NLSLs with external uniform Bragg grating in the case of the same grating length.