Polarization control in optical-fiber gyroscopes

Abstract

Analysis indicates that strict attention must be paid to polarization control in fiber gyroscopes in order to ensure drift stability. It is shown that the maximum drift rate that is due to faulty polarization control is proportional to the amplitude-extinction ratio for the rejected polarization channel. Consequently, in the worst circumstances, which on present evidence cannot be excluded, the intensity extinction for the rejected polarization channel in a typical fiber gyroscope must approach 10(-6). Options for achieving this control are indicated by the analysis.

Polarization and modal filters based on W-fibers Panda for fiber-optic gyroscopes and high-power fiber lasers

“…First, 2 it was set ε ¼ 0 (zero PNR), but for ε ≠ 0 an extremely severe limitation of ε 2 ∼ 120 dB was yielded. 4 However, then in it was shown in Refs. 5 and 6 that high birefringent (hi-bi) fiber coil together with broadband source strongly suppress PNR, so ε 2 ∼ 50 dB is enough.…”

Accurate Evaluation of Polarization Characteristics in the Integrated Optic Chip for Interferometric Fiber Optic Gyroscope Based on Path-matched Interferometry

“…The scattering-related term allows scattering with 90˚ polarization rotation of the incident field. In this study, the very low  of the imperfect polarizer is assumed to be zero for simplicity as described in [4,15]. The Jones matrix explains the phase shift due to pigtailed input/output PMFs is [16] For the case of the IOC chip, because there is also polarization rejection characteristic except for birefringence, the transfer matrix for the IOC chip can be expressed as product form.…”

“…In the development of navigation grade IFOG, it is necessary to pay attention to the birefringence induced polarization non-reciprocity caused by the considerable influence of imperfect polarization characteristics between constitutive optical components on the bias stability [3]. The related theories have been well established and many solutions have been suggested utilizing a polarizer with the common input/output port of the Sagnac closed loop [4][5][6]. Intensity-typed phase error due to the interference between the main polarization mode and the crosscoupled secondary polarization mode is bounded by the value proportional to the square of the amplitude extinction coefficient of the polarizer as follows [7], 2 2 ε ρ φ r e < Δ (1) where   is intensity-typed phase error due to the polarization cross-coupling,  is the amplitude extinction coefficient of the polarizer,  r 2 is the intensity ratio of the cross-coupled mode to the main polarization mode.…”

Fiber-Optic Gyroscopes

“…At first thought, it seems that the residual unfiltered non-reciprocity should be proportionnal to the intensity extinction of the filter. But it has been pointed out (16) that it actually depends on the amplitude (E-field) extinction coefficient which requires a much higher filter quality. In particular, a polarizer which suppresses any birefringence nonreciprocity above 10-7 rad, should have a cross polarization extinction of 140 dB (not of 70 dB) which is a stringent requirement for this essential component.…”