Patent
Laser fiber optic gyroscope having phase modulation
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TLDR
In this paper, a non-reciprocal phase modulation is introduced between the clockwise (CW) and counterclockwise (CCW) beams at a modulation frequency (f), and the detected signal is demodulated by mixing it with a reference signal at the same frequency and stepping the phase of the signal through successive increments of 90°, thereby to determine the inphase and quadrature components for each frequency monitored.Abstract:
In a laser gyroscope, a non-reciprocal phase modulation is introduced between the clockwise (CW) and counterclockwise (CCW) beams at a modulation frequency (f). The CW and CCW beams are combined on a detector and the intensity of the output is observed at the fundamental frequency (f) and the higher harmonics (e.g. 2f, 4f). At each frequency, the detected signal is demodulated by mixing it with a reference signal at the same frequency and stepping the phase of the signal through successive increments of 90°, thereby to determine the in-phase and quadrature components for each frequency monitored.read more
Citations
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Patent
Decreasing the effects of linear birefringence in a fiber-optic sensor by use of berry's topological phase
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References
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Patent
Optical fiber measuring device, gyrometer, central navigation and stabilizing system
Herve Lefevre,Philippe Martin +1 more
TL;DR: In this article, the phase difference between two waves in a SAGNAC ring interferometer was modulated in such a way that the gain of the channel for controlling the modulation was kept constant by producing a signal depending on the said gain.
Patent
Fiber optic gyro stabilized by harmonic components of detected signal
TL;DR: In this article, a phase modulator is inserted in one end of the circular optical path, by which the light waves are phase modulated, and the intensity of the interference light is detected, as an electric signal, by a photodetector.
Patent
Fiber optical rotation sensor utilizing the Sagnac phase difference
TL;DR: In this paper, a laser wave omitted from a laser diode is guided into a one directional optical coupler and is splitted into two laser waves by the coupler, and one of the splitted interference laser waves is then converted into an electric signal by the photodetector.
Patent
Switched state fiber optic gyroscope
TL;DR: In this paper, an improved fiber optic gyroscope with a substantial improvement in dynamic range and scale factor stability over a basic fiber-optic gyroswope is disclosed.
Patent
Method and device for detecting propagation time variations in a ring interferometer and application thereof to wave length control
Herve Lefevre,Didier Rolly +1 more
TL;DR: In this paper, a method and corresponding device are provided for detecting the propagation time variations in the ring of an interferometer and includes phase modulation of the contrarotating waves travelling through the ring by means of assymetric square waves at a period twice the initial propagation time.