Two or more lasers or other temperature sensitive optical devices can be disposed in an operating environment, for example in a common enclosure exposed to the environment. The environment can have a temperature that fluctuates, for example in connection with random events, weather, seasons, etc. Each laser's temperature can track the temperature of the environment in steps, with each laser following a distinct temperature track. The lasers can alternate outputting light into a wavelength division multiplexing channel. For example, during one timeframe, one laser can provide an optical communication signal having a wavelength complying with a wavelength division multiplexing criterion. During another timeframe, the other laser can provide an optical signal having substantially the same wavelength. Operating a laser at an elevated temperature can shorten laser lifetime. To mitigate temperature induced failure, a replacement laser can be engaged when a failure predictor, precursor, or indicator meets a threshold.