Reliability test procedures for tunable lasers

Widely tunable lasers are promising sources for future high-capacity dense wavelength division multiplexing and photonic switching systems. These devices can be used for sparing in the cold standby mode, restoring in hot standby restoring, rerouting wavelength rerouting or conversion, or fast switching in all-optical networks. Tunable lasers need to demonstrate some features such as wide tunability range, optical output power of 10 dBm or more, cost and structure similar to those of commercial DFB lasers. High performance devices would require low laser chirp, high modulation speed, small size and very high reliability. For system applications, requirements on the tunable laser reliability are very stringent. Reliability studies and appropriate related testing procedures are necessary to define stability of tunable lasers and their expected lifetime. In this paper we propose some reliability test "strategies" useful for qualification of tunable lasers with reference to some critical issues of the main technologies used to achieve the tunability feature.