DEPENDENCE OF POLARIZATION, GAIN, LINEWIDTH ENHANCEMENT FACTOR, AND K-FACTOR ON THE SIGN OF THE STRAIN OF INGAAS/INP STRAINED-LAYER MULTIQUANTUM WELL LASERS

The sign of the strain in a multiquantum well (MQW) active layer of an InGaAs/InP laser determines whether lasing occurs from the electron-heavy hole transition or from the electron-light hole transition. Lasing from the electron-light hole transition is reported to provide a much better performance than predicted by theory. It is concluded that this gives the best device performance, providing a higher differential gain, a lower threshold current, a record low linewidth enhancement factor of 1.5, and a K factor of 0.22 ns, potentially allowing a 3 dB modulation bandwidth of 40 GHz.