New LED-based high-brightness incoherent light source in the SWIR.

The first LED-pumped luminescent concentrator (LC) emitting in the short-wave infrared (SWIR) is reported. Low cost LEDs (at 940 nm) are used to pump a Yb,Er:Glass LC emitting at 1550 nm. The optical conversion efficiency of the system is optimized and studied in detail for several optical configurations. A total of 128 LEDs having an emitting surface of 1 mm2 and an irradiance of 51.6 W/cm2 , corresponding to a total pump power of 66 W, are used. Optimizing the output power out of a 100-mm-long LC in a continuous wave regime, a power of 850 mW is extracted from the 2.5 x 2 mm2 LC emitting surface area. The optical efficiency is then 1.29%. The performance of this luminescent concentrator is higher by one order of magnitude in term of radiance compared to an LED emitting at the same wavelength.