Abstract: A rotation speed measurement method based on a femtosecond optical frequency comb is provided. In the method, a rotation axis of a rotating object to be measured and an optical path main axis are coplanar, and perpendicular to each other, and a first converging lens focuses an emitting beam obtained by expanding the laser on a surface of the rotating object. A repetition frequency and a carrier-envelope offset frequency of the femtosecond optical frequency comb are locked during the measurement. A repetition frequency difference is read from a frequency counter. A rotation speed of the rotating object is calculated as follows: M = c ? ? ? f r 4 ? ? ? f r ? sin ? ? ? R = ? ? ? ? f r R .

Abstract: Disclosed is a photonic doppler velocimetry (PDV) system for ultra-high-speed instantaneous measurement, relating to laser velocity interferometry. The PDV system includes a laser velocity interferometry module, a microwave photonic module, and a data acquisition and signal processing module. The laser velocity interferometry module includes a continuous-wave laser, a circulator, a fiber optic probe, and a first photodetector. The microwave photonic module includes a femtosecond-pulse laser, a first dispersion optical fiber, a second dispersion optical fiber, a Mach-Zehnder (M-Z) modulator, and an optical fiber amplifier. The data acquisition and signal processing module includes a second photodetector, an oscilloscope, and a computer.

Abstract: A large-scale and high-precision absolute distance measurement system based on an all-fiber femtosecond laser, including: a first all-fiber femtosecond laser, a second all-fiber femtosecond laser, a fiber optic splitter, a first fiber optic circulator, a wavelength division multiplexer, an achromatic fiber collimator, a first fiber optic combiner, a second fiber optic combiner, a second fiber optic circulator, a semiconductor laser, a first photodetector, a second photodetector, and a data acquisition and processing module.

Abstract: A rotation speed measurement method based on a femtosecond optical frequency comb is provided. In the method, a rotation axis of a rotating object to be measured and an optical path main axis are coplanar, and perpendicular to each other, and a first converging lens focuses an emitting beam obtained by expanding the laser on a surface of the rotating object. A repetition frequency and a carrier-envelope offset frequency of the femtosecond optical frequency comb are locked during the measurement. A repetition frequency difference is read from a frequency counter. A rotation speed of the rotating object is calculated as follows: M = c ? ? ? f r 4 ? ? ? f r ? sin ? ? ? R = ? ? ? ? f r R .

Abstract: A dual femtosecond optical frequency comb generation device is provided. The device includes a pump source, a wavelength division multiplexer, a piezoelectric ceramic, an erbium doped fiber, a single mode fiber, a first fiber collimating mirror, a second fiber collimating mirror, and spatial optical path elements, a first quarter-wave plate, a first half-wave plate, a polarization beam splitting prism, an optical isolator, a second half-wave plate and a second quarter-wave plate, and further including a grating pair, the grating pair being composed of a first grating and a second grating and being provided between the polarization beam splitting prism and the optical isolator. The device introduces the light distance difference by using the grating pair, so as to generate dual femtosecond optical frequency combs with a difference in repetition frequency, and the repetition frequency difference can be adjusted by the pitch of the grating pair.