Low-frequency intensity noise resonance in an external cavity GaAs laser for possible laser characterization

The dependence of the (low-frequency) resonance of light intensity noise in an external-cavity GaAs laser on cavity length and bias current, combined with the dependence of the threshold current on the magnitude of the light feedback, is used to determine simultaneously the carrier recombination lifetime, the carrier injection at transparency, and the optical loss. The key to this technique is understanding the correction term to the relaxation oscillation frequency due to finite carrier density at transparency and the influence of the long external cavity transit time on the photon lifetime in the three-mirror cavity. The technique uses commercial lasers without modifying them and does not require fast electronics