Patent ID: 7515619

Claim:
An apparatus, comprising: a laser source to generate an optical signal; a power monitor optically coupled to monitor a power output of the laser source and to generate power feedback data indicative of the power output; a processor coupled to control the power output of the laser source in real-time in response to the power feedback data from the power monitor; a power regulator coupled to provide power to the laser source during operation of the laser source; and a hardware watchdog circuit coupled to receive an alternating current (“AC”) safety shutoff signal from the processor and further coupled to disable the power regulator when the AC safety shutoff signal is disrupted, wherein the hardware watchdog circuit includes: a high-pass filter coupled to receive the AC safety shutoff signal from the processor; a peak rectifier coupled to rectify the AC safety shutoff signal; and a discharge resistor coupled to discharge an output of the peak rectifier, if the AC safety shutoff signal fails.