LINEWIDTH ENHANCEMENT FACTOR FOR INGAAS/INP STRAINED QUANTUM-WELL LASERS

The linewidth enhancement factor α in an InGaAs/InP strained-layer multiple quantum well (MQW) laser emitting near 1.55 μm has been determined from the spontaneous emission spectra below threshold. The active layers in the MQW structure in this device are under 0.7% compressive strain. The measured α at the lasing wavelength is 2.0. The calculation of α using interpolated bandstructure parameters shows that it varies rapidly with injected carrier density and the calculated value for our device is close to the measured value. The small α for strained MQW InGaAs lasers should result in performance improvement that are advantageous for lightwave system application.