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Abstract This study investigates the propagation properties and radiation forces on Rayleigh dielectric particles produced by novel sine-modulated Gaussian beams (SMGBs) because of the unique focusing properties of four independent light intensity distribution centers and possessing many deep potential wells in the output plane of the target laser. The described beams can concurrently capture and manipulate multiple Rayleigh dielectric spheres with high refractive indices without disturbing each other at the focus plane. Spheres with a low refractive index can be guided or confined in the focus but cannot be stably trapped in this single beam trap. Simulation results demonstrate that the focused SMGBs can be used to trap particle in different planes by increasing the sine-modulate coefficient g. The conditions for effective and stable capture of high-index particles and the threshold of detectable radius are determined at the end of this study.

Primary angular vibration calibration devices based on laser interferometers play a crucial role in evaluating the dynamic performance of inertial sensing devices. Here, we propose a sinusoidal phase-modulated angle interferometer (SPMAI) to realize angular vibration measurements over a frequency range of 1–1000 Hz, in which the sinusoidal measurement retro-reflector (SMR) and the phase generation carrier (PGC) demodulation algorithm are adopted to track the dynamic angle variation. A comprehensive theoretical analysis is presented to reveal the relationship between demodulation performance of the SPMAI and several factors, such as phase modulation depth, carrier phase delay and sampling frequency. Both the simulated and experimental results demonstrate that the proposed SPMAI can achieve an angular vibration measurement with amplitude of sub-arcsecond under given parameters. Using the proposed SPMAI, the frequency bandwidth of an interferometric fiber-optic gyroscope (IFOG) is successfully determined to be 848 Hz.

In recent years, tapered optical fibers (TOFs) have attracted increasing interest and developed into a range of devices used in many practical applications ranging from optical communication, sensing to optical manipulation and high-Q resonators. Compared with conventional optical fibers, TOFs possess a range of unique features, such as large evanescent field, strong optical confinement, mechanical flexibility and compactness. In this review, we critically summarize the multimode interference in TOFs and some of its applications with a focus on our research project undertaken at the Optoelectronics Research Centre of the University of Southampton in the United Kingdom.

A high sensitivity optical fibre temperature sensor is demonstrated based on a balloon-shaped bent single-mode (BSBS) fibre structure where the fibre retains its original protective polymer coating. The BSBS fibre structure can be simply realized by bending a coated straight single-mode fibre into the balloon shape using a section of silica capillary tube. By adjusting the bending radius of the balloon-shaped fibre section, a modal interferometer between the core mode and the coating mode can be effectively implemented at a suitable bending radius. Considering the intrinsically high thermo-optical coefficient and thermal expansion coefficient of the polymer coating, the BSBS fibre structure offers excellent temperature sensing performance. Experimental results show that the temperature sensitivity is as high as  −2465 pm °C−1 with a resolution of 0.008 °C over the temperature range of 20.7 °C–31.7 °C. Based on its simple fabrication process, very low cost, and experimentally determined high sensitivity coupled with good repeatability, the temperature sensor described in this article could be a competitive candidate in many temperature sensing applications. [ABSTRACT FROM AUTHOR]