A solid-core tellurite glass fiber with 1.8 dB/m loss at 1.55 ìm was made by using the built-in casting preform fabrication method and rod-in-tube fiber drawing technique. Pumping a 10 cm fiber piece with picosecond pulses of 3-5?10(12) W/cm(2), 0.1% of the fundamental power limited by the coherence length of 0.3-5 ìm was converted into visible third-harmonic power tunable over a broad near-IR wavelength ranging from 1500 to 1680 nm. Frequency conversion from the mid-IR to near-IR was found to be even more efficient due to the longer coherence lengths of 12-20 ìm in the wavelength range of 2200-2500 nm.
Glass Infrared Rays