Influence of nonlinear dispersion of the refraction index on the Sagnac effect in semiconductor ring lasers

Abstract

Mutually contradicting previously reported theoretical results on the effects of a dispersive active medium in a ring laser on its sensitivity to rotation are critically analyzed. A measure of the rotation rate in the active ring resonator is the beating frequency ∆ν between the counterpropagating waves whose frequencies are shifted in opposite directions due to the Sagnac effect. ∆ν is shown to be inversely proportional to the group index of the medium filling the cavity. A comparison of the results obtained considering the resting and rotating frames confirms the applicability of Fresnel's original expression for the optical drag effect to the analysis of the Sagnac effect in an active laser gyro. The frequency splitting ∆ν is sensitive to dispersion via the group refractive index.

Theoretical design of a superluminal helium–neon ring laser via coupled passive cavities

“…Recently, the concept of utilizing critical anomalous dispersion in a ring laser to enhance the rotation sensitivity has been studied by many groups [1][2][3][4][5][6]. Such anomalous dispersion can be achieved by various means, including alkali metal vapors [2,6], semiconductor lasers [3,4], coupled optical resonators [7,8], Brillouin optical fibers [9,10] and spectral hole burning [11].…”

“…Recently, the concept of utilizing critical anomalous dispersion in a ring laser to enhance the rotation sensitivity has been studied by many groups [1][2][3][4][5][6]. Such anomalous dispersion can be achieved by various means, including alkali metal vapors [2,6], semiconductor lasers [3,4], coupled optical resonators [7,8], Brillouin optical fibers [9,10] and spectral hole burning [11]. In these fast-light enhanced cavities, the dispersion is tailored such that the frequency of the laser shifts in response to a rotation of the cavity or an equivalent displacement in the mirrors by an amount larger than the case without the tailored dispersion [2,7].…”