Tunable third-harmonic generation in a solid-core tellurite glass fiber

A solid-core tellurite glass fiber with 1.8?dB/m loss at 1.55?μm 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?μm 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?μm in the wavelength range of 2200-2500?nm.