title: Theoretical Design of a Depolarized Interferometric Fiber-Optic Gyroscope (IFOG) on SMF-28 Single-Mode Standard Optical Fiber Based on Closed-Loop Sinusoidal Phase Modulation with Serrodyne Feedback Phase Modulation Using Simulation Tools for Tactical and Industrial Grade Applications.
abstract: This article presents, by means of computational simulation tools, a full analysis and design of an Interferometric Fiber-Optic Gyroscope (IFOG) prototype based on a closed-loop configuration with sinusoidal bias phase- modulation. The complete design of the different blocks, optical and electronic, is presented, including some novelties as the sinusoidal bias phase-modulation and the use of an integrator to generate the serrodyne phase-modulation signal. The paper includes detailed calculation of most parameter values, and the plots of the resulting signals obtained from simulation tools. The design is focused in the use of a standard single-mode optical fiber, allowing a cost competitive implementation compared to commercial IFOG, at the expense of reduced sensitivity. The design contains an IFOG model that accomplishes tactical and industrial grade applications (sensitivity ≤ 0.055 °/h). This design presents two important properties: (1) an optical subsystem with advanced conception: depolarization of the optical wave by means of Lyot depolarizers, which allows to use a sensing coil made by standard optical fiber, instead by polarization maintaining fiber, which supposes consequent cost savings and (2) a novel and simple electronic design that incorporates a linear analog integrator with reset in feedback chain, this integrator generating a serrodyne voltage-wave to apply to Phase-Modulator (PM), so that it will be obtained the interferometric phase cancellation. This particular feedback design with sawtooth-wave generated signal for a closed-loop configuration with sinusoidal bias phase modulation has not been reported till now in the scientific literature and supposes a considerable simplification with regard to previous designs based on similar configurations. The sensing coil consists of an 8 cm average diameter spool that contains 300 m of standard single-mode optical-fiber (SMF-28 type) realized by quadrupolar winding. The working wavelength will be 1310 nm. The theoretical calculated values of threshold sensitivity and dynamic range for this prototype are 0.052 °/h and 101.38 dB (from ±1.164 × 10(-5) °/s up to ±78.19 °/s), respectively. The Scale-Factor (SF) non-linearity for this model is 5.404% relative to full scale, this value being obtained from data simulation results.
authors.affiliation: Department of Electrical Engineering, University of Oviedo, Ed. Torres Quevedo, Gijón Campus, Gijón 33204, Asturias, Spain. ramonjose.perez@lugo.uned.es.
authors.forename: Ramón José
authors.initials: RJ
authors.lastname: Pérez
authors.affiliation: Department of Electrical Engineering, University of Oviedo, Ed. Torres Quevedo, Gijón Campus, Gijón 33204, Asturias, Spain. ialvarez@isa.uniovi.es.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Álvarez
authors.affiliation: Department of Electrical Engineering, University of Oviedo, Ed. Torres Quevedo, Gijón Campus, Gijón 33204, Asturias, Spain. jmenguita@uniovi.es.
authors.forename: José María
authors.initials: JM
authors.lastname: Enguita
keywords: Integrated-Optical-Circuit (IOC); Interferometric Fiber-Optic Gyroscope (IFOG); Lyot depolarizer; Phase Modulator (PM); Phase-Sensitive-Demodulation (PSD); Super-Luminiscent-Laser-Diode (SLD); closed-loop IFOG configuration; serrodyne wave