Multiple-Fiber and Multiple-Wavelength Confocal Sensing With Diffractive Optical Elements

Adding a diffractive element to the imaging optics of a fiber-based confocal sensor greatly enhances the chromatic dispersion of the optics. This can be exploited to enhance the sensing range and resolution of the sensor. Several examples are given using one and two fibers with simultaneous dual wavelength illumination to probe the displacement of a target object.