位相同期ループモデルによる分布帰還型半導体レーザの相互注入同期の解析

Abstract

Mutual injection locking between two distributed feedback laser diodes is analyzed with a simple phase-locked-loop model derived from the Van der Pol equation. Some characteristics of the mutual injection locking, especially the linewidth controllability, are clearly explained with this model. An analytical expression for the dependence of the linewidth on the laser output powers is obtained. To confirm the validity of the model, linewidths of two distributed feedback laser diodes under the mutually injection locked condition were measured and compared with the results calculated with the phase-locked-loop model. The dependence of the linewidths on the laser output powers agreed well with the calculated ones.