Photonics for angular rate sensing is a well-established research field having very
 important industrial applications, especially in the field of strapdown inertial
 navigation. Recent advances in this research field are reviewed. Results obtained in
 the past years in the development of the ring laser gyroscope and the fiber optic
 gyroscope are presented. The role of integrated optics and photonic integrated
 circuit technology in the enhancement of gyroscope performance and compactness is
 broadly discussed. Architectures of new slow-light integrated angular rate sensors
 are described. Finally, photonic gyroscopes are compared with other solid-state
 gyros, showing their strengths and weaknesses.

Photonic technologies for angular velocity sensing

Resonator micro optic gyro (RMOG) with a waveguide-type ring resonator is a promising candidate for applications requiring small, light and robust gyros. In optical passive ring resonator gyros, clockwise (CW) and counter clockwise (CCW) lightwaves are phase-modulated at different frequencies to reduce the backscattering induced noise. The effectiveness of this technique, however, is determined by the carrier suppression level. In this paper, the influence of the carrier suppression level on the gyro performance is examined experimentally for an RMOG system with a silica waveguide resonator. In our experiment, carrier suppression is applied onto both the CW and the CCW lightwaves at the same time to achieve higher total suppression. We show that carrier suppression as high as 100 dB can be achieved by optimizing the amplitude of the phase modulation. A bias stability of 0.46 /s in 50 seconds is demonstrated in an RMOG with a silica waveguide ring resonator having a ring length of 7.9 cm. This is the best result reported to date, to the best of our knowledge, for waveguide-type ring resonator gyros of this size.

Reduction of Backscattering Induced Noise by Carrier Suppression in Waveguide-Type Optical Ring Resonator Gyro

Resonator micro optic gyro (RMOG) is a promising candidate for applications requiring small, light and robust gyros. In optical passive ring resonator gyros, clockwise and counter clockwise lightwaves are modulated at different frequencies to reduce the backscattering induced noise. The effectiveness of this technique, however, is determined by the carrier suppression level. Accurate modulation index and high environmental temperature stability is required for achieving high total carrier suppression for the traditional single phase modulation technique (SPMT). In this paper, we propose an RMOG based on the double phase modulation technique (DPMT). Compared with the traditional SPMT, two additional phase modulations are added to provide additional carrier suppression. It is found that the control accuracy of the modulation index and temperature stability is relaxed more than 30 times. It is easily performed for reducing the backscattering error below the shot noise limited sensitivity. The modulation parameters in the DPMT are analyzed and optimized. Based on the optimum parameters of the DPMT, a bias stability of 1.85 × 10−4 rad/s is successfully demonstrated in the polarization maintaining silica waveguide resonator with the length of 7.9 cm. This is the best result reported to date, to the best of our knowledge, for a waveguide type passive ring resonator gyro.

Polarization maintaining silica waveguide resonator optic gyro using double phase modulation technique.

Nowadays, optical devices and circuits are becoming fundamental components in several application fields such as medicine, biotechnology, automotive, aerospace, food quality control, chemistry, to name a few. In this context, we propose a complete review on integrated photonic sensors, with specific attention to materials, technologies, architectures and optical sensing principles. To this aim, sensing principles commonly used in optical detection are presented, focusing on sensor performance features such as sensitivity, selectivity and rangeability. Since photonic sensors provide substantial benefits regarding compatibility with CMOS technology and integration on chips characterized by micrometric footprints, design and optimization strategies of photonic devices are widely discussed for sensing applications. In addition, several numerical methods employed in photonic circuits and devices, simulations and design are presented, focusing on their advantages and drawbacks. Finally, recent developments in the field of photonic sensing are reviewed, considering advanced photonic sensor architectures based on linear and non-linear optical effects and to be employed in chemical/biochemical sensing, angular velocity and electric field detection.

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Recent advances in integrated photonic sensors.

Resonator micro optic gyro (RMOG) with a wave- guide-type ring resonator is a promising candidate for applications requiring small, light and robust gyros. In optical passive ring res- onator gyros, clockwise (CW) and counter clockwise (CCW) light- waves are phase-modulated at different frequencies to reduce the backscattering induced noise. The effectiveness of this technique, however, is determined by the carrier suppression level. In this paper,theinfluenceofthecarriersuppressionlevelonthegyroper- formance is examined experimentally for an RMOG system with a silica waveguide resonator. In our experiment, carrier suppres- sion is applied onto both the CW and the CCW lightwaves at the same time to achieve higher total suppression. We show that car- rier suppression as high as 100 dB can be achieved by optimizing the amplitude of the phase modulation. A bias stability of 0.46 /s in 50 seconds is demonstrated in an RMOG with a silica waveguide ring resonator having a ring length of 7.9 cm. This is the best result reported to date, to the best of our knowledge, for waveguide-type ring resonator gyros of this size.

Reduction of Backscattering Induced Noise by Carrier Suppression in Waveguide-Type Optical

We report the first demonstration of silica wave- guide optical passive ring resonator gyro OPRG based on the phase modulation spectroscopy technique. The ring resonator is composed of a 6-cm-long silica waveguide. Ob- served from the resonance curve, the free spectral range FSR of the resonator, the full width at half maximum FWHM of the resonance curve, the finesse F of the reso- nator, and the resonance depth are 3.4 GHz, 62 MHz, 54.8, and 70%, respectively. The detection sensitivity of this OPRG will be 7.310 5 rad/s. In the experiments, there is an acoustic-optical modulator AOM in each light loop. We lock the lasing frequency at the resonance frequency of the silica waveguide ring resonator for counterclockwise CCW lightwave; the frequency difference between the driving fre- quencies of the two AOMs is equivalent to the Sagnac fre- quency difference caused by gyro rotation. Thus, the gyro output is observed. © 2006 Society of Photo-Optical Instrumentation Engineers.

https://www.spiedigitallibrary.org/journals/optical-engineering/volume-45/issue-8/080506/Waveguide-type-optical-passive-ring-resonator-gyro-using-phase-modulation/10.1117/1.2280645.pdf

Zhonghe Jin

Papers

Waveguide-type optical passive ring resonator gyro using phase modulation spectroscopy technique