BEND INSENSITIVE OPTICAL FIBRE WITH IMPROVED HYDROGEN RESISTANCE Russian patent published in 2016 - IPC G01V8/16 

FIELD: physics.

SUBSTANCE: optical fibre comprises a core which contains a photosensitive material which increases the refraction index. The core has a first refraction index and minimal concentration of the photosensitive material required to form fibre Bragg gratings. The fibre also comprises a depressed cladding surrounding the core and having a second refraction index which is less than the first refraction index. An outer cladding surrounds the depressed cladding and has a third refraction index which is greater than that of the depressed cladding. The invention further discloses a second version of the optical fibre without a depressed cladding and a device for determining medium parameters in a well based on the optical fibre.

EFFECT: providing a high numerical aperture and less content of a photosensitive dopant while maintaining the required level of photosensitivity, as well as good bending resistance and hydrogen resistance.

20 cl, 6 dwg