Red-emitting diode laser efficiently pumps upconversion fiber laser

Red-emitting diode laser efficiently pumps upconversion fiber laser

Dave Funk and Gary Eden at the University of Illinois at Urbana-Champaign (Urbana, IL) have succeeded in pumping an upconversion fiber laser with a low-power red-output semiconductor diode laser. In what is claimed to be the first such demonstration, a 22-cm-long holmium-doped fluorozirconate (ZBLAN) fiber was pumped at 643 nm by the 30-mW output of an SDL (San Jose, CA) diode laser. The fiber laser produced several lines in the 547- to 549-nm region, with a maximum output power of 1.2 mW for 10.2 mW of launched pum¥power, yielding an overall efficiency of about 12% with respect to launched pum¥power.

The launched pump-power threshold was 3.5 mW, lower than any other upconversion fiber laser by at least a factor of two, according to Funk. Efficiency for launching the pum¥into the fiber was determined to be about 43%. Funk expects that, with output coupling and fiber length optimization, 3-5 mW of green output will be obtainable with a 30-mW pum¥diode laser