All-fiber linear sampling device for absolute distance measurement

An all-fiber linear sampling device for dual-comb time-of-flight (TOF) distance measurement is demonstrated. We studied the impact of optical filter and adjustable attenuator on the symmetry of the interferometric beat-note, the optimization of which is crucial for TOF extraction. In an absolute ranging experiment, a ranging precision of 49 um is obtained at an update rate of 2 kHz and the precision can be improved to 7 um with 100 ms averaging time. This technique shows the potential of high precision absolute ranging in many practical industrial scenarios.