Alexey Komissarov

High-brightness fiber coupled pumps

Advanced high volume applications require pumps with high power, high brightness, and high power efficiency. New generation devices meet all of these challenging requirements, while still maintaining the advantages of distributed pumping architecture including high reliability inherent to single emitter sources. Based on new-generation long-cavity diode chips, new pumps are capable of more than 60W CW power ex-fiber output (100 μm core diameter) into NA ~ 0.12. Peak power efficiency stays over 60%. All of the above is provided at room heatsink temperature, maintained by basic air- or water-cooling.

9xx-nm single emitter pumps for multi-kW systems

High-power high-brightness multimode edge emitting pumps have been developed. Comprehensive development efforts have resulted in 3 mm-long cavity diodes with far-field divergence reduced down to 26°. Output in excess of 20W CW from 90 μm-wide aperture single emitter was demonstrated for the first time. Peak power was reached at 25A CW driving current and was limited by power supply. Peak CW power efficiency was as high as 67%. Two coolerless package types designed to operate up to 10W output and up to 20W output are reported. About 95% fiber coupling efficiency into NA<0.12 was demonstrated in the entire range of driving currents for both types of pumps. For packages of the later design efficiency over 50% is maintained up to 16W CW ex-fiber output. Diode junction overheat above heatsink temperature is less than 20°C up to ~ 18W ex-fiber output.

AlGaInAs/GaAs record high-power conversion efficiency and record high-brightness coolerless 915-nm multimode pumps

High power highly-efficient AlGa(In)As/GaAs multimode diodes operating at 915 nm range have been developed. 2 mm long-cavity Chips-On-Submount demonstrate 72% peak power conversion efficiency at 25°C heatsink temperature. Peak power efficiency over 50% was recorded up to 130°C heatsink temperature. CW power launched at 7°C heatsink temperature from 20 um wide aperture devices is around 8.5 W and is thermally limited. This output power level translates into record-high brightness on the facet: > 65 MW/cm2. Device reliability assessment indicates high potential of such devices to operate reliably at high electrical and optical power densities.

8xx - 10xx nm highly efficient single emitter pumps

Higher reliability and power efficiency achieved with low-demanding cooling make single emitter diodes a more effective pump source than monolithic laser diode arrays. Continuously improving performance and increasing brightness of single emitter pumps are accompanied with a steady reduction of cost of pumping (dollar-per-watt). Performance advantages do not compromise reliability of the pumps. These features ensure that single emitter diodes are the most effective solution even for multi-kWatt systems pumping. Here we report on a recent progress in single-mode and multi-mode edge-emitting diodes.

High-volume manufacturing of 8XXnm-10XXnm single emitter pumps by MBE growth technique

We report on GaAlInAs/GaAs lasers manufactured by the industry’s biggest production MBE tool. This MBE reactor allows for growth on 23 three-inch diameter wafers at a time, at a cost that compares favorably with the MOCVD method. Data on chip-on-submount performance and uniformity across the entire MBE-growth area are presented and compared to the quality of material produced by smaller size production MBE tools. We also present data on performance characteristics of spatially combined fiber coupled passively cooled single emitter-based pumps. The data include performance characteristics of devices operating at ~805nm and ~975nm wavelengths when driven in CW, QCW and pulsed modes; both pumps use ~105μm core diameter fiber to launch power confined within NA<0.15.

Highly-efficient high-power pumps for fiber lasers

We report on high efficiency multimode pumps that enable ultra-high efficiency high power ECO Fiber Lasers. We discuss chip and packaged pump design and performance. Peak out-of-fiber power efficiency of ECO Fiber Laser pumps was reported to be as high as 68% and was achieved with passive cooling. For applications that do not require Fiber Lasers with ultimate power efficiency, we have developed passively cooled pumps with out-of-fiber power efficiency greater than 50%, maintained at operating current up to 22A. We report on approaches to diode chip and packaged pump design that possess such performance.