Bias current dependence of FM efficiency in tunable three-electrode DFB lasers

The carrier-induced frequency modulation (FM) mechanism is investigated for tunable three-electrode DFB lasers. The bias current dependence of the FM efficiency in actual devices is successfully explained in a concise manner. The direction of the frequency shift (blue or red shift) depends on the position of the lasing mode in the stopband, which is determined by both the carrier and the thermal effects on the refractive index under a given bias condition.<
>