HIGHLY RELIABLE DIODE ENSEMBLES FOR DIRECT DIODE APPLICATIONS AND PUMPING SOLIDSTATE LASERS

摘要

The historic approach to providing >5W of direct diode power for solid-state laser pumping or direct diode applications has been to use bar diodes. In this paper we present an alternative to the traditional bar diode approach. Specifically, we present a distributed, single-emitter, diode laser architecture. This ensemble architecture features many benefits, beginning with the single-emitter diodes. These diodes have statistically proven mean time to failures (MTBF) on the order of 500,000 hours. Additionally, when these diodes are modulated at frequencies ranging from 0.25 Hz to 2 Hz our data suggests the modulation has minimal effect on lifetime, which is critical for many direct diode applications. We will review what can be expected in lifetime from an ensemble of single-emitters, and this will reveal a greater than 90% probability that a 50W ensemble will survive for 20,000 hours. In both the discussion on single-emitter lifetime and ensemble lifetime, variation of the underlying assumptions can provide significantly different results. This variability can be used to tailor the ensemble’s expected performance the designer’s requirements. Finally, there are several qualitative advantages of using a distributed architecture approach, such as the relative ease of air- cooling at higher powers and the ability to fully fill the fiber at higher powers.