ABSTRACT
Figure l schematically shows the top view emitting PCDFB laser with an aspect ratio of tan 8 = A2/A1 between the two periods. There are two equivalent propagation directions, P 1 and P2, which form equal angles of e with respect to the facet normal. The 2D pattern allows simultaneous diffraction in three directions (e.g., from P1 to P2, - P~, and - P2) , which leads to strong spectral filtering (similar to the I D DFB action) and coupling of different points across the laser stripe (similar to the a-DFB laser).8
