A statistical approach to laser certification

This paper proposes a statistical methodology for certifying the longevity of individual lasers to be used in an undersea communications cable. In general, the strategy is to extrapolate the slope of a degradation parameter such as i (the current necessary to maintain a given level of optical-output power) when the laser is subjected to elevated temperatures. This extrapolation is made from time t1 (when the test terminates) to time tp (the system life, as contracted in time by an Arrhenius relationship). An important part of the process is the calculation of the variability of the estimated current value at time tp, used to estimate the probability that it will exceed a critical failure level if; lasers that exceed a predetermined probability will be rejected. The methodology presented here must, in the absence of actual data on lasers to be used in an undersea communications cable, be tentative with respect to details; modifications may well be necessary to accommodate idiosyncrasies of the manufacturing process and the testing equipment.