Implementation of Optical Micro Displacement Sensor System using Single Mode Coupler for Lasers at (532 & 810) nm

In this paper implementation of optical micro displacement sensor system using single mode 5050 coupler based on intensity modulated technique is presented. A single mode fiber coupler (L=2.5 m) has coupling ratio 0.5, excess loss 0.2 dB, directivity 60dB and 9m core diameter is used. Two optical sources IR laser diode (810 nm) and green laser diode (532 nm) with optical power meter to detect the variation in output laser power due to micro displacement for movement body under test, a planar mirror and spectrum analyzer to detect the change of the light intensity as function of the displacement were utilized. Results show that the sensor is able to detect object displacement in front of mirror. The sensor characteristics are measured at the slope. Good sensitivity of the sensor 202.8 W / mm for IR laser source and sensitivity of the sensor 411.2W / mm for Green laser source.