Mid-Wave Infrared Polarization-Maintaining Single Mode Fiber

Most infrared lasers emit light that is strongly polarized and require polarization-maintaining fibers to preserve the as-launched polarization state as it propagates through the fiber. While polarization maintaining fibers are commercially available in the visible, near infrared and short wavelength infrared, the silica glasses used for these fibers have extremely high optical loss in the mid infrared. For the spectral region 3-6 µm, other glasses such as telluride, fluoride, or sulfide must be used as a fiber material. Despite years of research, there are no commercially available polarization maintaining fibers for this spectral range. High performance single-mode polarization maintaining MIR fibers have been identified as a key enabling technology for next-generation Infrared Counter Measures and chemical and explosive detection.  The proposed single-mode polarization maintaining fiber addresses the mechanical and optical deficiencies of earlier designs by using an index guided solution.  The microstructured index-guiding fiber design is compatible with fluoride, telluride, sulfide glasses and delivers birefringence >10-3. The Phase I program demonstrated the feasibility of developing novel PM fiber by testing the simplified design. In Phase II the PM fiber matching the design with required birefringence will be manufactured and fully characterized.