Theoretical and Experimental Investigation of Quantum Noise Induced Sensitivity Limit of a Fast Light Ring Laser Gyroscope

In a Fast-Light Ring Laser Gyroscope (FRLG), the group index is vanishingly small.nbsp; The Sagnac effect induced shift in the resonance frequency of each of two counter-propagating lasers, for a given rotation rate, is amplified by a factor equaling the inverse of this group index, compared to that for a conventional ring laser gyroscope (RLG).nbsp; This scale factor enhancement coefficient (SFEC) can be as high as a million.nbsp; If the quantum noise limited uncertainty in the laser frequency for an FRLG is the same as that for an RLG for otherwise identical operating parameters, this would imply that the factor of enhancement in measurement precision (FEMP) for an FRLG is the same as the SFEC.nbsp; However, based on analogy with similar effects in a parity-time symmetric system, it has been suggested that the quantum noise limited uncertainty for an FRLG may be larger than that for an RLG, due to the so-called Petermann factor, thereby reducing the FEMP to a value smaller than the SFEC.nbsp; We will carry out theoretical as well as experimental work to establish the maximum possible value of the FEMP that can be achieved under experimentally achievable conditions.nbsp; In one track, we will carry out two new types of theoretical modeling for the FRLG to determine how the FEMP varies as a function of the operating parameters: one based on propagating the field using a quantum-enabled finite division time domain technique in the presence of random spontaneous emissions of photons, and the other based on re-ordering the operators in the temporal correlation function.nbsp; In the second track, we will use a robust version of a Rb based superluminal laser, which employs a cavity enclosed in a vacuum chamber and highly stabilized pump lasers, to measure the value of the FEMP.nbsp; The measurements will be compared with the theoretical models, and used to guide modifications thereof until agreement is achieved.nbsp; This will pave the way for further refinement and miniaturization of the FRLG in Phase II.