Effect of d.c. bias level on the spectrum of GaAs lasers operated with short pulses

Experimental results on stripe-geometry GaAs/GaxAl1¿xAs lasers show that the emission spectrum when operated with short pulses is very dependent on the d.c. bias level. If the bias is below threshold, many modes are excited and the spectral bandwidth is about 30 Å, but a bias just above threshold ensures virtually single-mode operation with about 1 Å bandwidth.