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Optical Rotation Sensor and its manufacturing method

aerospaceAttitude estimationOptical rotation sensorResonant gyroscopeRobot-assisted surgery

Introduction

The invention is a Photonic Crystal Ring Resonator, comprising an optical ring resonator (RR) formed by a one-dimensional photonic crystal (1D PhC) waveguide, and a bus waveguide. It is suitable as key element of a Resonant Micro Optic Gyroscope (RMOG), useful for the determination of the rotation rate into an inertial frame. The use of the invention in a RMOG leads to very high performance, in terms of resolution and compactness.

Technical features

The invention is about an optical rotation sensor, comprising an optical ring resonator (RR) formed by a one-dimensional photonic crystal (1D PhC) waveguide, and a bus waveguide. A light input section of the bus waveguide is connected to a light source, and a light output section of the bus waveguide is connected to a light detector. The bus waveguide is optically coupled to the ring resonator within a coupling area, which is located between the light input section and the light output section of the bus waveguide. A rotation of the optical sensor induces a shift of the frequency of a resonance area (or a plurality of resonance areas) close to a band edge of a photonic band gap of the ring resonator, which the optical rotation sensor is configured to measure. The usage of the Sagnac effect together with the very high Q-factor of the band edge resonances allows achieving a detection limit being about three orders of magnitude lower than a conventional ring resonator gyroscope having the same geometrical characteristics. A gyroscope shot noise limited resolution of 10-3 grad/h has been calculated with an estimated volume of 5 cm3. The optical rotation sensor may comprise a silicon layer and a doped silica layer, within which the ring resonator and the bus waveguide are formed, provided above the silicon layer. Using a low index contrast technology (e.g. Silica on Silicon, SOS) allows achieving a higher uniformity of the fabrication process and a lower scattering loss for the waveguiding elements (i.e. bus waveguides, unperturbed waveguide regions).

Possible Applications

  • Aerospace;
  • Satellite;
  • Robot-assisted surgery;
  • High sensitive biochemical sensors;
  • Optical applications.

Advantages

  • High resolution;
  • Compact dimensions and low mass;
  • Low manufacturing costs;
  • Good mechanical proprieties.