Systems, methods, and devices are described for in-situ testing of vertical-cavity surface-emitting lasers (VCSELs), VCSEL arrays or laser diodes (each a laser). Testing may comprise bias voltage measurements of one or more lasers. Embodiments may comprise one of a laser, a driver circuit providing a bipolar drive to the laser, and a sensing circuit to measure and/or monitor damage or degradation of the laser. The bipolar drive may comprise a pulsed forward bias output configured to produce a light output during an on-time of the laser, and a pulsed reverse bias output during an off-time of the pulsed forward bias output. The pulsed outputs may comprise a variable, chirped frequency. One or more of a reverse leakage current, and a junction temperature may be measured to monitor a state of health of the laser.