摘要： Chalcogenide-glass-based optical fibers are excellent photonic platforms for nonlinear applications in the mid-IR region due to their wide transmission window, tunable dispersion and high optical nonlinearity. There is particular interest in combining the chalcogenide fiber platform with polarization-preserving properties as this will allow polarization-dependent measurements while minimizing detrimental effects and thus enable new applications in interferometric techniques, gas sensing, integrated-optic devices and optical coherence tomography. In this work, for the first time to our knowledge, we demonstrate mid-IR supercontinuum (SC) generation in a highly birefringent polarization maintaining photonic crystal fiber (PM-PCF). The PM-PCF was drawn using the casting method from As38Se62 glass which features a transmission window from 2-10 μm and a high nonlinear refractive index up to 1.13×10-17 m2/W [1,2]. To introduce strong birefringence, an asymmetric arrangement of air holes was used as shown in Fig. 1(a). The PCF cross section consists of 36 circular air holes in 3 rings with 2 larger air holes adjacent to the core. The (approximate) core diameter (i.e. distance between two large air holes) is ~8.1 μm and the outer diameter of the PCF is 125 μm. The group velocity dispersion and group birefringence for the fundamental mode (computed from the SEM image) are shown in Fig. 1(b). The fiber has a zero-dispersion wavelength around 4.5 μm and, at this wavelength, a large birefringence of 6×10-4 such that strong polarization maintaining properties are expected. In our experiments, a 25cm long PM-PCF was pumped with 250 fs pulses at 4 μm (i.e. the normal dispersion regime) using the same experimental setup for MIR SC generation as previously described in Ref. [3]. Figure 1(c) shows the generated SC spectra with different output power. For a pump power of 135 mW, we obtained a SC spectrum from 3.1-6.02 μm with an average output power of 11 mW. Pumping close to the zero dispersion wavelength with the pump at 4.53 μm yielded comparable spectral broadening but at much lower input pump power of 62 mW as shown in Fig. 1(d). In this case, we were able to measure the polarization dependence of the SC spectra by changing the coupling angle through rotation of the fiber. These results demonstrate the potential of chalcogenide PM-PCF for polarized SC generation, and work is underway to optimize the spectral generation and polarization dependency using detailed numerical modelling.