Temperature and external-cavity tuning of high-power GaAsP laser diode

Wide-range temperature tuning of 733 nm GaAsP laser diode has been combined with tuning by external grating. Temperature tuning (down to 87K) yields the 40 nm range (from 733nm to 693 nm) with reduced threshold currents and external efficiencies above 1 W/A. High power up to 2 W is achieved in the full tuning range. Fine tuning with grating allows for narrower linewidth but the tuning range decreases from 9 nm at 293 K to zero at 130 K. The wavelength range covered by temperature tuning fills the gap between GaAsP quantum-well lasers and InGaP/AlGaInP red lasers. High power lasers operating between 690 nm and 730 nm could be useful in medical applications involving photo-dynamic therapy. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim