Investigations of thermal crosstalk in laser arrays for WDM applications

Our studies on the thermal crosstalk of laser arrays with integrated thin-film heaters involved theoretical as well as experimental investigations. Comparing the effects of intentional geometrical variations of the device design, we found that the relative thermal crosstalk depends critically on the distance between the active area and the film heater. The most striking result is that a minimization of the thermal resistivity of the device does not always lead to a reduced thermal crosstalk. We demonstrate that an additional heat barrier close to the active region and/or an improved heat transfer between the submount and the heat sink may reduce the relative thermal crosstalk, a result completely unexpected from intuitive considerations.