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Mid-infrared supercontinuum generated from a single-cladding Tm-Ho co-doped fiber

We report on the mid-infrared supercontinuum laser output using a short piece of single-cladding Tm-Ho co-doped fiber, pumped by a 1565 nm pulsed laser. The seed laser was amplified using a two-stage Er-doped master oscillation power amplifier (MOPA). The seed laser was amplified to 260.8 mW with repetition rate of 100 kHz. The amplified 1565 nm pulse laser passed through a piece of 500 m long single-mode 9/125 G652D communication fiber, then the laser was injected into a 2 m long 9/125 Tm-Ho co-doped fiber. The laser had output power of ~ 20 mW, and the laser’s spectrum was measured by an optical spectrum analyser (YOKOGAWA). By changing the 1565 nm seed laser’s repetition rate and pulse duration, mid-infrared supercontinuum was generated. The energy levels of Tm3+ and Ho3+ icons acted with the different wavelength of the pulse laser, then flat and broadband mid-infrared supercontinuum between 1800 nm ~ 2200 nm was generated. The output power can be scaled up by increasing the 1565 nm laser’s power directly. This supercontinuum generated by single-cladding Tm-Ho co-doped fiber may provide meaningful reference for mid-infrared supercontinuum generation using other rare-dearth-doped fibers.