Eliminating additional laser intensity modulation with an analog divider for fiber-optic interferometers

Additional laser intensity modulation (LIM) will degrade performance of fiber-optic interferometric sensors in which phase generated carrier demodulation techniques are utilized. In this paper, a new method to eliminate the additional LIM of a sinusoidal modulated fiber ring laser through an analog divider is presented. Experimental results show not only LIM but also intensity noise peak caused by relax oscillation are eliminated simultaneously by the analog divider. System becomes more stable, and gets a higher performance with adoption of this method. Factors influencing system performance are also analyzed.