INTELLIGENT DRIVERS USING OPTICAL SENSING

The development of a practical, easily-implemented device that can extend the lifetimes of existing diode lasers would lead to extended service and lower costs and cost-of-ownership. Such a device extends the lifetimes of diode lasers by shutting off the supply current when formation of a potentially damaging current filament appears likely. This allows the diode to return to its initial state with no memory of filamentation. We have artificially generated optical transients by applying current pulses atop the normal, regulated drive currents of laser diodes to observe the result of such aberrant behavior of the laser’s properties and lifetime. We have studied the optical and electrical behavior to correlate excursions in both that indicate performance-degrading faults. The plan is to use such optical transients as predictors of potentially damaging faults, and to use this to trigger a protection circuit that will shut down the drive current for a short time and allow the diode to return to a safe state before resuming operation. The optically-triggered protection circuit combined with a constant current supply will then be tested on LDAs to demonstrate that it increases the working lifetime of off-the-shelf laser diodes.