In this work, we numerically study the effect of high-orderλ /4 phase-shift grating in laterally-coupled distributed feedback (LC-DFB) lasers performance. It is well known that single-mode operation is improved by introducing λ/4 phase-shift grating in conventional DFB lasers. However, introducing λ/4 phase-shift region increases the optical intensity around this region and results in strong longitudinal spatial-hole burning (LSHB). To flatten the longitudinal carrier density distribution, we have numerically studied the effect of the radiation modes on high-order LC-DFB lasers using a modified time-domain travelling-wave algorithm. It is shown that, the degree of LSHB can be effectively reduced when considering high-order LC-DFB lasers with grating duty-cycle tailored to optimal values. LC-DFB laser cavity with high-order grating shows a strong non-uniformity of the carrier density distribution. However, as we finely engineer grating features, LSHB is highly reduced and high single mode suppression ration can be achieved.

Date Published: 24 October 2012
PDF: 10 pages
Proc. SPIE 8412, Photonics North 2012, 841219 (24 October 2012); doi: 10.1117/12.2001395

Published in SPIE Proceedings Vol. 8412:
Photonics North 2012
Jean-Claude Kieffer, Editor(s)