Serrodyne modulator in a fibre-optic gyroscope

The paper describes the behaviour of a serrodyne modulator in a closed-loop fibre-optic gyroscope. The general form of the driving waveform is described. A closed-loop computer model is used to investigate the behaviour of such a modulator and its associated errors in a gyroscope. Experimental results are included which show agreement with the model. It is concluded that certain of these errors affect the scale factor of the gyro and its linearity. To reduce the errors to acceptable levels it is necessary to control peak phase and minimise flyback time. The value of flyback time must be known to provide compensation in a closed-loop gyro.