Effects of carrier spatial hole burning and structure-dependent nonlinear gain in frequency modulation characteristics of GaAs quantum well external cavity lasers

We derive, we believe for the first time, an expression for the chirp-to-power ratio (CPR), i.e. the ratio of the frequency modulation to the intensity modulation for quantum well lasers which includes effects the carrier transport from separate-confinement-heterostructure (SCH) layers to the quantum wells, spatial hole burning in the lateral dimension of the quantum wells, and intrinsic material gain compression. The model includes the photon lifetime and percentage bias current above threshold as scaling parameters. We compare the model with data obtained from a quantum well GaAs laser and a channel-substrate planar (CSP) structure laser both in external cavities.<>