| 摘要 |
PURPOSE:To enable the detection of a phase difference DELTAtheta with good sensitivity by forming two sets of separated optical paths, detecting cos(DELTAtheta) and sin (DELTAtheta) in the respective separated optical paths, making the functions for the linear combination of both and utilizing the function of the best sensitivity. CONSTITUTION:The outputs of photodetectors 11, 12, 13, 14 are designated as D1, D2, D3, D4. Since there are pi/2 phase shifters in the separated optical paths, the output of the D1 is D1=2E0<2>(1+sinDELTAtheta). The output of the D2 is D=BE0<2> (1-sinDELTAtheta). From these equations, sin(DELTAtheta) is determined in the following way: sin(DELTAtheta)(D1-D2)/(D1+D2); similarly, cosDELTAtheta is determined by the following equation: cosDELTAtheta=(D3-D4)/(D3+D4). The n-pieces of following eigenfunctions are defined in the -pi/2<DELTAtheta<pi/2 range from sinDELTAtheta and cosDELTAtheta: Si=ai1sinDELTAtheta+ ai2cosDELTAtheta, (where i=1, 2,..., n) and DELTAtheta is determined from the value of the function Si. |
