Experimental investigation of the 2.1-um single-mode Tm-Ho:KYF laser

We report on the development and comprehensive characterization of a room-temperature single-mode 2-?m Tm-Ho: KYF laser. A maximum CW output power of ~ 70mW at the central wavelength of 2.078 ?m has been obtained. Using a 5-mm long intracavity birefringent filter the single-mode emission wavelength can be tuned over a range of ~ 40 nm. Both frequency and relative intensity noise have been investigated showing a 1-ms emission linewidth of ~ 600 kHz and an intensity noise spectrum that is quantum-noise limited for Fourier frequencies higher than 1MHz.