FIBRE-OPTIC GYROSCOPE Russian patent published in 2014 - IPC G01C19/64 

FIELD: measurement equipment.

SUBSTANCE: invention relates to gyroscope development equipment. A fibre-optic gyroscope (FOG) includes a multiturn closed loop from optic fibre in the form of a single-mode birefringent light waveguide, an emitter and a photoreceiver, two branchers, a polariser, a phase modulator and a phase detector, as well as an amplifier, a filter and a generator. The emitter is connected through the first brancher to the first input/output of the polariser connected with the second input/output through the second brancher to the corresponding first input/output of a fibre circuit, as well as connected with the second optic input/output through a phase modulator to this brancher. With that, the first brancher is also connected to the optic input of the photoreceiver with an electrical output through the amplifier and the filter of the phase detector connected to the first input, the output of which is also FOG output, and the second input of which is connected to the output of the generator that is simultaneously connected to the electrical input of the phase modulator. The emitter and the photoreceiver are connected to the first brancher with pieces of the single-mode birefringent light waveguide and the first and the second branchers are connected to the polariser as well by means of pieces of such a fibre; with that, the fibre circuit, branchers, the polariser and the phase modulator are made on a single piece of fibre without any joints. Length of the piece attaching the polariser to the first brancher that is either more or less by three times than the length of the piece attaching the polariser to the second brancher. With that, length of the smaller piece of the above pieces exceeds fibre depolarisation length, but is less by nine times than length of the fibre piece attaching the emitting module to the first brancher. The invention relates to development techniques of gyroscopes based on use of the Sagnac effect and can be used at manufacture of fibre-optic gyroscopes (FOG). The essence of the invention consists in the fact that fibre-optic gyroscope (FOG) contains a multiturn closed loop of optic fibre (hereinafter referred to as a fibre circuit) in the form of a single-mode birefringent light waveguide, an emitter and a photoreceiver, two branchers, a polariser, a phase modulator and a phase detector, as well as an amplifier, a filter and a generator; with that, the emitter is connected with an optic output through the first brancher to the first optic input/output of the polariser, which is connected with its second optic input-output through the second brancher to the first corresponding input/output of the fibre circuit, as well as connected through the phase modulator to that brancher with its second optic input/output; with that, the first brancher is also connected to the optic input of the photoreceiver, which is connected with its electrical output through in-series connected amplifier and filter to the first input of the phase detector, the output of which is also a FOG output, and the second input of which is connected to the output of the generator that is simultaneously connected to the electrical input of the phase modulator; with that, the emitter and the photoreceiver are connected to the first brancher with pieces of the birefringent optic fibre (a single-mode birefringent light waveguide), and the first and the second branchers are connected by means of pieces of such a fibre to the polariser; with that, the fibre circuit, branchers, the polariser and the phase modulator are made on a single piece of the fibre without any joints; with that, length values of pieces attaching the polariser to the branchers differ by three times; with that, length of the smaller piece of the above pieces exceeds fibre depolarisation length, but is less by nine times than length of the fibre piece attaching the emitter to the first brancher Length of the piece attaching the polariser to the first brancher can be either more or less than the length of the piece attaching the polariser to the second brancher. The technical result of the invention use consists in providing the possibility of maximum filtration degree of a useful signal under practical conditions of restricted functioning of individual FOG components, and as a result, an increase of percentage of yield ratio (as per the criterion of initial displacement and its stability) of products due to localisation of the main defects and selection of fibre lengths between optic components of all-fibre FOG, at which secondary waves occurring as a result of defects will have temporary delays exceeding the coherence time of an emission source With that, interference efficiency of secondary waves with the main waves (their mutual coherence) is considerably reduced, and therefore, FOG zero shift generated by secondary waves is reduced.

EFFECT: technical result consists in possibility of providing maximum filtration degree of a useful signal.

1 dwg