New method to reduce effective linewidth enhancement factor /spl alpha//sub eff/ of DSM lasers using optical complex coupling

We propose a new method to reduce effective linewidth enhancement factor /spl alpha//sub eff/ by using complex coupled (CC) structure with anti-phase combination. It is found that the introduction of CC structure into a distributed reflector (DR) laser leads to extremely low /spl alpha//sub eff/(< 1). It is also found that a CC-DFB laser has a possibility of low /spl alpha/sub eff/(/spl tilde/ 2) even with a bulk active layer.