An optical fiber microdisplacement sensor utilizing thermal source and diffraction grating

An optical fiber microdisplacement sensor is developed utilizing a thermal source and a diffraction grating as a dispersive component. The present sensor is simple to demonstrate and it uses inexpensive experimental configuration compared to the existing displacement sensors. A multimode fiber with a core/cladding ratio of 65.5/125 is used as the guiding medium. The optical system is optimized to find a minimum spot size using the Code V optical design software. Finally, a theoretical analysis is presented for the compensation of source variation.