Theoretical description and design of a fast-light enhanced helium-neon ring-laser gyroscope

Abstract

We describe an enhanced rotation sensor involving an active helium-neon (HeNe) ring laser coupled to a passive enhancement resonator, which has been named a fast-light-enhanced HeNe ring-laser gyroscope (RLG). Theoretical rotation sensitivity enhancements as large as two orders of magnitude are presented. The physical effect responsible for the increased rotational sensitivity is the anomalous dispersion of the enhancement resonator, which produces a larger beat frequency as compared to a standard HeNe ring-laser gyroscope (RLG) as the laser cavity is rotated. We present the layout of the fast-light enhanced HeNe RLG, and we provide the theoretical modeling of the enhanced rotational sensitivity. A design is presented for the red HeNe (632.8 nm). The beat frequency is calculated with respect to rotation rate, which defines the useful range of operation for this highly sensitive RLG. Considerations for practical issues including laser-mirror reflectivity precision, unsaturated laser gain, and cavity-length stability are discussed.

Sensitivity Enhancement of Ring Laser Gyroscope Using Dielectric-Graphene Photonic Crystal

“…There are several types of gyroscopes, including ring laser gyroscopes (RLG) [2]. Due to the importance of this device in various applications, especially military applications, extensive efforts have been made to increase the sensitivity of the device and improve its performance including using fast-light-enhanced He-Ne ring-laser gyroscope [3], superluminal ring laser [4], multilayer optical coatings on one of the gyroscope mirrors [5], nonlinear effects [6] and so on. The maximum sensitivity measured in all of these methods was of the order of 6 10 [7,8].…”

Theoretical analyses of resonant frequency shift in anomalous dispersion enhanced resonant optical gyroscopes

“…The resonant frequency difference between clockwise (CW) and counterclockwise (CCW) directions can be measured accurately by optical heterodyne technique like in the cases of Ring Laser Gyroscopes (RLGs), which are active resonant optical gyroscopes. In recent years, there has been interest in the development of resonant optical gyroscopes with novel materials234, structures56789101112 and physical effects13141516171819, among which the utilization of fast light for sensitivity enhancement is a potential technique1516171819. Actually, it is the strongly anomalous dispersion that amplifies the Sagnac RFS as well as allows superluminal light propagation.…”

“…There are two schemes to generate anomalous dispersion in ROGs, i.e. coupled-resonator structures151617 and steep negative dispersion materials1819.…”

“…In the superluminal helium–neon RLGs151617, the amplification of RFS is achieved by replacing one mirror in the traditional ring laser cavity with auxiliary passive cavities, where a theoretical rotation sensitivity enhancement of about two orders of magnitude is demonstrated15. The performance of such gyros can be regulated by changing the mirrors’ properties in these coupled cavities16 or the round-trip length of the ring lasers and the coupled cavities17.…”

“…Obviously, the RFS will be amplified with the group velocity be faster than the speed of light in vacuum if n g is less than 1. This is the reason that such amplification is connected with fast light1516171819. Nevertheless, the modification factor is not accurate as some approximations are made in their derivations, which lead to some inappropriate conclusions.…”