تجزیه و تحلیل حساسیت از یک تشدید کننده حلقه فیبر بر اساس باند گپ نوری هوا هسته فیبر

The fiber ring resonator (FRR) is the core sensing element in a resonator fiber optic gyroscope (R-FOG), and its sensitivity determines the performance of the R-FOG. This paper presents an in-depth analysis of the sensitivity of the FRR which is made of an air-core photonic-bandgap fiber (PBF), in which the characteristics of the FRR using PBF are compared with that of an FRR using a conventional single mode fiber. When using PBF instead of conventional fiber, it is found that the resonance curve is changed, and the sensitivity of the FRR is decreased a little when a narrow spectral linewidth laser is used. However, the degree of the decrease in sensitivity is not big enough to deny the advantages of PBF in improving the performance of the R-FOG considering that PBF is much better than conventional fiber in reducing the drift. Also, the optimal parameters of the directional coupler for sensitivity are discussed. It is found that the optimal intensity coupling coefficient when using PBF is nearly two times larger than that when using conventional fiber, and the optimal coupler intensity loss when using PBF is smaller than that when using conventional fiber.

Using the Sagnac effect [1], a resonator fiber optic gyro (R-FOG) has potential as a high accuracy inertial rotation sensor [2]. However, the Rayleigh backscattering [3] and [4], the Kerr [5] and [6], Faraday [7] and [8] and thermal effects [9] and [10] generally limit the accuracy of the R-FOG. Air-core photonic-bandgap fiber (PBF) is a new kind of fiber [11] and [12]. Since the optical mode is mostly confined to the air-core when the light travels in the air-core PBF, the four effects in an air-core PBF would be smaller than that in a conventional fiber [11] and [13]. Therefore, in order to improve the performance of the interference fiber optic gyro (I-FOG), Kim et al. have proposed an I-FOG based on an air-core PBF [13]. The air-core PBF could be used in the R-FOG to improve its performance also; therefore, it is meaningful to study the R-FOG based on an air-core PBF [14] and [15]. The fiber ring resonator (FRR) is the core sensing element in the R-FOG [16]. The sensitivity of the FRR plays a large role in determining the performance of the R-FOG [17] and [18]. The analysis of the sensitivity has been done for a FRR using a conventional single mode fiber [17]; however, an in-depth analysis of an FRR based on an air-core PBF has not been done. The characteristic parameters (such as the refractive index and the attenuation loss of the fiber) of the air-core PBF and the conventional fiber are very different, and this would lead to the resonance characteristics of the FRR with different fibers to be different, which would finally give rise to the difference in the sensitivities [1] and [17]. This paper discusses the sensitivity of a FRR based on an air-core PBF, and a comparison of the sensitivities which occur upon the use of an air-core PBF and conventional fiber are presented. Finally, the optimal parameters of the directional coupler to achieve optimal sensitivity are compared when using PBF and conventional fiber.

The sensitivity characteristics of the FRR based on an air-core PBF has been analyzed, and it is compared with that of the FRR based on a conventional fiber. It is concluded that the resonance curve using PBF is different from that using conventional fiber. The difference of the resonance curves finally causes the difference of the sensitivities, and it is found that the sensitivity would be decreased under narrow spectral linewidth laser when using PBF instead of conventional fiber; however, the degree of the decrease is not big enough to dispel the advantages of the PBF in improving the performance of the R-FOG because the air-core PBF is much better than conventional fiber in reducing several important optical effects such as the Kerr effect. Therefore, using air-core PBF instead of conventional fiber still has the potential to improve the performance of the R-FOG significantly. In addition, the optimal parameters of the directional coupler for sensitivity are considered, and it is found that the optimal intensity coupling coefficient when using PBF is nearly two times larger than that when using conventional fiber, and the optimal coupler intensity loss when using PBF is smaller than that when using conventional fiber. These theoretical results are helpful to further study and optimize the R-FOG based on the air-core PBF.