Fabrication and applications of air-clad photonic lanterns

Todays optical communication system is predominantly based on single mode fibers that allows the transmission of data in a single fundamental mode. The continued demand for higher data capacity is driving the optical communication system to a new area called space division multiplexing. Mode division multiplexing is a type of space division multiplexing, where multiple spatial modes in a few mode fiber is used for parallel data transmission. The development of mode division multiplexed transmission system requires efficient conversion of light from single mode fiber to light in few mode fibers. A photonic lantern is a fiber based mode convertor device that allows this conversion of light from single modes to light in higher order modes. Conventional photonic lanterns are fabricated by threading the single mode fibers in a low refractive index capillary tube. These custom-made capillary tubes are not that easily accessible. Through this project, we suggest a new type of photonic lanterns, which are fabricated without
these outer capillary tubes. The air surrounding the single mode fibers form the new low refractive index cladding. This new technique will make the photonic lantern fabrication cheaper and accessible to all. Design and fabrication of these air-clad photonic lanterns are done in this project. The fabricated photonic lanterns are tested in mode division multiplexing transmission setups, where parallel transmission of data through two spatial channels are demonstrated. The fabricated photonic lanterns are also combined with an optical frequency domain reflectometry set up and simultaneous Rayleigh sensing of bend loss in the two modes of a few mode fiber is demonstrated.