Analysis of the low-frequency noise of 89X nm-range single-mode VCSELs

This paper presents the results of experimental investigations of low-frequency relative intensity noise and phase noise of single-mode 89X nm-range vertical-cavity surface-emitting lasers (VCSELs) with different photon lifetimes. The lasers are based on a hybrid vertical microcavity design with carrier injection through intracavity contact layers and composite Bragg gratings. Analysis of the low-frequency amplitude noise of the VCSELs showed that the noise spectrum in the frequency range from 100 Hz to 10 kHz has a 1/f-noise trend, transitioning to white noise at frequencies above 10 kHz. The dependence of the amplitude noise on the laser's optical power has a W-shaped form. An increase in temperature leads to growth in both amplitude and phase noise, both at a fixed operating current and at comparable optical power of laser radiation. In the frequency range of 1−100 kHz, the achieved amplitude noise level does not exceed -120 dB/Hz. Meanwhile, in the 10−100 kHz frequency range, the phase noise level saturates at 0.6−1.1·10⁹ Hz²/Hz (depending on temperature and optical power) for devices with a characteristic photon lifetime of ~ 8.5 ps. The obtained results allow the use of the developed VCSELs in compact quantum sensors of various types.