Bias characteristics of a multioscillator ring laser gyro with consideration of differential losses

Bias characteristics of the multioscillator ring laser gyro using Faraday cell (FLAG) have been investigated with both numerical simulation and experiment methods. We calculated the bias as a function of magnetic field strength and detuning for several FLAGs with different parameters. The results give some interesting findings. Firstly, the FLAG bias as a function of magnetic field strength and detuning have a cross point which corresponds to a feature bias if differential losses are not considered. It means that at the feature magnetic field strength, the bias of the FLAG is insensitive to the variation of detuning and at the feature detuning, the bias of the FLAG is insensitive to the variation of magnetic field strength. Secondly, differential direction loss and magnetic circular dichroism loss have influences on the feature magnetic field strength while differential polarization loss does not have. Experimental results verified the rule qualitatively and indicated the FLAG always had a feature detuning. The intrinsic bias characteristics are significant to the development of a high performance FLAG.

► The bias of the FLAG can be insensitive to detuning variation. ► The bias of the FLAG can be insensitive to magnetic field strength variation. ► Linear fitting method is used to dig the rule buried in quantum noise. ► The experimental FLAG has a strict feature detuning insensitive to magnetic field.