Optical Waveguide Polariser

About

In-fibre optical polarisers have a number of industrial and scientific applications, in optical fibre telecommunications, electrical current sensing, and high-power laser isolation. Existing solutions, such as fixing crystals to polished fibres or the formation of helical fibre structures, have limited available wavelengths and highly complex production processes, and therefore have high costs and a low production rates. These technologies can also suffer high optical losses. Bulk polariser solutions are unsuitable for high power devices and are affected by mechanical vibration. This novel in-fibre polariser allows for high optical power and boasts a high polarisation extinction ratio (PER) over a broad range of wavelengths (600-2000nm). The device incorporates a variably tilted fibre Bragg grating inscribed in the fibre with UV-inscription. This allows a direct inscription of the pattern, without the need to remove the fibre cladding. The devices are low cost, as the fabrication process is simple, and are not limited by the type of fibre. The device is currently in use by the US Air Force for laser guide star applications.