Fabrication of low losses chalcogenide photonic crystal fibers by molding process

Chalcogenide glasses are known for their large transparency in the mid infrared and their high refractive index (>2). They present also a high non linear refractive index (n2), 100 to 1000 times larger than for silica. An original way to obtain single-mode fibers is to design photonic crystal fibers (PCFs). Until now, chalcogenide PCFs are realized using the stack and draw process. However this technique induces defects, like bubbles, at the capillaries interfaces, causing significant scattering losses. Until now, the best transmission obtained was 3dB/m at 1.55µm. The poor PCF transmission reduces significantly their application potential. So, we present a new efficient method to realize low-loss chalcogenide PCFs. This original method by molding permits to reduce the optical losses down to 1dB/m at 1.55µm and less than 0.5dB/m between 3 and 5µm for an As-Se PCF. Furthermore, this molding method can be used for different compositions. Single mode fibers were realized. Moreover, very small core fibers were realized with this method, obtaining a non linear coefficient of 15 000W-1km-1 with an As-Se PCF. We also observed self phase modulation at 1.55µm on a fiber with a 2.3µm2 mode area.