Effect on FOG caused by non-uniform distribute magnetic field

Abstract

Using matrix optics and optical propagation theory, a model for bias errors of an optical fiber gyroscope (FOG) caused by the nonuniform distribute magnetic field has been deduced. Based on the above model, the effect on the FOG caused by the nonuniform distribute magnetic field and common circuit board is also analyzed. Results indicate that, ⅰ) the nearer of distance between the center of magnetic field and the fiber loop, the bigger of the bias errors of FOG will be; ⅱ) relationship between bias and magnetic field direction is a inclined sine, which becomes more gradient when the distance between the center of magnetic field and the fiber loop is nearer; ⅲ) the bias error caused by the nonuniform magnetic field is bigger than that caused by uniform magnetic field of equal intensity, when R < 5r ( center of nonuniform magnetic field in fiber loop) or R < 0.5r ( center of nonuniform magnetic field out of fiber loop); ⅳ) the direction of magnetic axis is changed by the exit of nonuniform magnetic field; ⅴ) the common circuit board which radiate intensity is very weak can also cause unstable and direction related of the FOG’s output. Above conclusions may be useful for understanding the effect of actual magnetic field.