Reliability issues in pump laser packaging

It is anticipated that in the near future erbium doped fiber amplifiers (EDFA) will find their way into new optical networking concepts, ranging from WDM systems in the metro sector to loss-compensation in optical switching. In order to be viable, these applications demand a technology, which in comparison to traditional systems is more compact, less costly, and more readily integrated, yet offers comparable performance and reliability. These demands are probably most significant for the EDFA pump laser. Our contribution discusses general reliability issues in pump module packaging, with special emphasis on how they will likely be addressed in future designs. As an example of this emerging trend in pump laser packaging we will present some of the design concepts and the reliability performance of our recently introduced family of un-cooled 980 nm pump modules. For 980 nm pumps, the key target specifications defined by new applications may be summarised as follows: chip reliability < 500 FIT; target package reliability < 500 FIT; wavelength-stabilised output power 200 mW; roadmap to 300 mW; operating case temperature 0°C to 70°C; power consumption < 1 W; packaging technology opens path to sustainable cost reduction. We and other manufacturers have recognised that these requirements can only be addressed by a significant differentiation of conventional 980 nm module technology, notably the transition to cooler-less operation. Our design features an 8-pin ceramic (Al₂O₃) miniDIL housing and a near planar assembly technology. The rated output power of this product family is 200 mW.