N-doped-silica-core polarization maintaining fibre for gyros and other sensors for application in space industry

PANDA-type optical fibre with nitrogen-doped silica as core and pure silica as cladding material is fabricated and tested. The fibre demonstrates birefringence as high as 5·10^-4, polarization holding h-parameter 2·10^-5 m^-1, loss 1.5 dB/km at a wavelength of 1.56 microns and 250 dB/km at 0.4 microns. Gamma radiation induced loss is found not exceeding 5-10 dB/km at a dose of 2-10 kGy, which is by an order of magnitude lower as compared to similar fibre with Ge-doped silica in the core.