Harmonic distortion in 1.55-mu m vertical-cavity lasers

We investigate second and third order harmonics in the analog modulation re sponse of InP-GaAs fused 1.55-mum vertical-cavity lasers (VCLs), These devi ces exhibit the lowest threshold current as well as the highest temperature of continuous-wave operation of any electrically pumped long wavelength VC L, Near the resonance frequency, harmonic distortion is dominated by electr on-photon interaction, and it is close to the distortion measured with in-p lane lasers, At low frequencies, distortions seem to be dominated by carrie r transport effects. At 1 GHz modulation frequency, we measure a maximum sp ur-free dynamic range of 64 dB Hz(1/2) for second-order harmonic distortion and 81-dB Hz(2/3) for third-order harmonic distortion.