Fig. 1. (a) Experimental setup of the MIR SC fiber source. PA, pre-amplifier; CMS, cladding mode stripper; DCF, double-clad fiber; SCF, single-clad fiber; ISO, 2 μm optical isolator (Thorlabs, IO-K-2000); L, fiber length. (b) Spectral distribution of the Er/Yb amplifier (blue line), output of the fiber isolator (green line), and the Tm amplifier (black and red lines).

Fig. 2. (a) Spectral distribution of the Tm amplifier (black line) injected into fluoride fibers. The SCs from the 20-m ZBLAN and 20-m InF3 fibers are shown with red, green, and blue lines, respectively. Corresponding SC output average powers are indicated in parentheses in the legend. (b) Measured attenuation and (c) calculated dispersion spectra of ZBLAN and InF3 fibers. (d) Calculated mode field diameter (MFD) of fundamental modes in ZBLAN, InF3, and silica fibers as a function of wavelength.

Fig. 3. (a) Spectral distribution at the output of the 20-m long InF3 fiber (sample A) for different pump powers. (b) Spectral distribution at the output of the InF3 fiber (sample A) for different fiber lengths. The laser power from the Tm amplifier was fixed to 2.3 W.

Fig. 4. (a) 10-dB spectral bandwidth as a function of the SC output power. (b) SC output power as a function of the Tm amplifier output power. (c) Spectral distribution at the output of fluoride fibers. The laser power from the Tm amplifier was fixed to 2.3 W for the three cases presented, and the SC output powers are indicated in parenthesis.

Table 1. Characteristics of Fluoroindate-Fiber-Based SC Laser Sources^a

Table 2. Fiber Parameters Summary^a