Determination of hysteresis loops for tunable external cavity semiconductor lasers

Investigations have been made to determine relations between the oscillation frequency ν of the ECLD and threshold carrier density N (orgain coefficient g),refractive indexn as well as mode frequency Nν of the diode. Afterwards,the perturbation method has been adopted to check the stability of the state represented by the points on the N-ν curve. The results indicate that two segments of vital importance for the formation of the loop,which were formerly misjudged as representing non stable states,represent stable state. Therefore,the hysteresis loop on the N-ν curve can be accomplished.