We report on the performance of monolithic, polarization maintaining, Er-doped photonic crystal fibers (PCF) and amplifiers operating in the eye-safer wavelength regime from 1.55-1.6 um. As part of this effort, we have developed novel 6x1+1 pump/signal combiners for air-clad photonic crystal fibers with six 0.22 NA, 200/220 um pump input fibers and a 25/250 PM signal fiber that allow efficient pump and signal coupling to the air-clad Er-doped PCF. These etched air taper combiners have been demonstrated at the kilowatt level under 976 nm pumping and perform an efficient brightness transformation from 0.19 NA, 1532 nm fiber coupled diode pumps into the 0.6 NA air-clad Er-doped PCF with a measured pump throughput efficiency of 88-92% and a signal throughput of 65-80% with a PER of <18 dB. These novel combiners have been efficiently spliced to 40 um core, 200 um pump cladding Er-doped PCFs providing high efficiency resonantly pumped, monolithic, eye-safer PCF fiber lasers and amplifiers. Using grating stabilized 1532 nm pump diodes, our current experiments have demonstrated single transverse mode operation of both monolithic eyesafer PCF lasers and amplifiers at the multi-Watt level with slope efficiencies of over 55%.

Date Published: 8 November 2012
PDF: 5 pages
Proc. SPIE 8547, High-Power Lasers 2012: Technology and Systems, 85470P (8 November 2012); doi: 10.1117/12.974668

Published in SPIE Proceedings Vol. 8547:
High-Power Lasers 2012: Technology and Systems
Harro Ackermann; Willy L. Bohn, Editor(s)