DFB semiconductor lasers based on reconstruction-equivalent-chirp technology.

A distributed feedback (DFB) semiconductor laser with equivalent phase shifts and chirps is proposed for the first time to our knowledge and is investigated numerically. As an example, it is shown that the desired lambda/4 phase shift in a phase-shifted laser can be obtained equivalently by a specially designed sampling structure instead of an actual phase shift, while the external characteristics are unchanged. This novel DFB structure is advantageous in that it can be fabricated by standard holographic technology. Hence, the proposed scheme is expected to provide a low-cost method for fabricating a high-performance DFB semiconductor laser with complex structures.