Related Experiment Video
Updated: Aug 5, 2026

Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements
Published on: February 28, 2016
Integration of Gaussian-mode emission and multimode fiber reception with Doppler-shifted interval analysis for
Abstract:
Rotational Doppler velocimetry (RDV) has emerged as a key technique for sensing and identifying spinning objects. However, existing fiber-based RDV systems generally rely on customized mode-selective couplers for orbital-angular-momentum generation or mode filtering, resulting in increased complexity and cost. Here, we propose a fiber-assisted RDV scheme that combines Gaussian-mode emission, multimode-fiber (MMF) reception, and Doppler-interval analysis without requiring such devices. The scheme is theoretically analyzed and experimentally demonstrated over a rotational-speed range of 0-5000 r/min. Spectral autocorrelation enables robust interval extraction, yielding relative errors below 0.2% and standard deviations below 5 r/min. Robust operation is further verified under lateral displacement, angular misalignment, and varying surface roughness. Moreover, larger MMF core diameters are shown to enhance optical collection and improve signal-to-noise ratio. These results demonstrate a simple, low-cost, and practical route toward engineering-oriented rotational Doppler LiDAR systems.
Related Concept Videos
Doppler Effect - II
Doppler Effect - I
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
IR Spectroscopy: Molecular Vibration Overview
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Relative Motion Analysis using Rotating Axes
However, to express the relative position of point B relative to point A, an additional frame of reference, denoted as x'y', is necessary. This additional frame not only translates but also rotates relative to the fixed frame, making it instrumental in...
Relative Motion Analysis using Rotating Axes - Acceleration
Time differentiation is...

