A linearly swept laser source over broadband with a fast sweep rate and narrow linewidth is realized using a novel optoelectronic scheme based on a multi-wavelengths (mutually coherent) injected distributed feedback (DFB) laser. Under the condition of multi-wavelengths injection, the injection-locking and four-wave mixing (FWM) process can occur simultaneously in the DFB laser, inducing a swept laser source with a sweep range of 100 GHz and sweep rate of 10 THz/s. Furthermore, with the phase noise character analyzation of the swept laser source, the phase noise deterioration due to the radio frequency (RF) signal is studied quantitatively. Besides the influence of the RF signal noise, the phase noise deterioration in the FWM process can be suppressed completely with the phase-locked pump beam and signal beam based on the injection-locking principle. This low phase noise swept laser source with sub-kilohertz linewidth could have wide applications in lidar.This paper presents a low loss suspended core microstructured fiber with ultra-high birefringence for terahertz wave guidance. The finite element method (FEM) with a perfectly matched layer is applied to investigate different important properties including effective material loss (EML), birefringence, dispersion, confinement loss, and percentage of power flow through the core. The suspended elliptical core in the design creates asymmetry and results in an unprecedented value of birefringence. The simulated results using FEM at 1 THz show an extremely ultra-high birefringence (the highest, to the best of our knowledge) of 0.1116, a nominal EML of 0.04716cm-1, a negligible confinement loss of 2.65×10-7cm-1, a higher power fraction in the core air of 35%, and an effective modal area of 1.24×105µm. The advancement in technology makes the fabrication possible. The proposed fiber could be used satisfactorily in the terahertz regime for various polarization-preserving applications and coherent communication.A high spectral resolution lidar (HSRL) for simultaneously detecting vertical wind, temperature, and the backscattering ratio in the troposphere is developed. The atmospheric temperature and vertical wind are determined by the Rayleigh scattering spectrum width and Mie scattering spectrum Doppler shift, respectively. The influence of temperature and the backscattering ratio on vertical wind measurement accuracy is also analyzed. The temperature and backscattering ratio affect the wind measurement, which produces the vertical wind offset. A correction considering the effects of the method is conducted considering real-time and on-site temperature profiles and the backscattering ratio to correct wind measurement sensitivity. Measurements of HSRL taken under different weather conditions (fine and hazy days) are demonstrated. Good agreement between the HSRL and the radiosonde measurements was obtained considering lapse rates and temperature inversions. The maximum temperature offsets were 1.3 and 4 K at a height of 1.5 km on fine and hazy days, respectively. Then, real-time and on-site temperature profiles and backscattering ratios were applied to correct the real-time and on-site wind. The corrected wind profiles showed satisfactory agreement with the wind profiles acquired from the calibrated wind lidar. The maximum detection offsets of the retrieved wind speed were reduced from 1 m/s to 0.55 m/s and from 1 m/s to 0.21 m/s, respectively, which were decreases of 0.45 and 0.79 m/s in fine and hazy days after correction of sensitivity. It is evident that the corrected wind method can reduce the influence of temperature and the backscattering ratio on the wind measurement and the offset of vertical wind. selleck inhibitor The reliability of the method is also proven.The paper presents theoretical formulas for calculation of diffraction by perfect infinite and finite amplitude gratings with Fresnel and Fraunhofer approximations. Further, general formulas for diffraction by an imperfect diffraction grating are derived where edges of the grating are described with general harmonic functions. Such a formalism provides enough power to accurately characterize imperfections of diffraction gratings, and it serves as a simple tool for a solution to a diffraction problem.Channeled spectropolarimeters (CSPs) are capable of estimating spectrally resolved Stokes parameters from a single modulated spectrum. However, channel crosstalk and subsequent spectral resolution loss reduce the reconstruction accuracy and limit the systems' scope of application. In this paper, we propose a spectral-temporal modulation strategy with the aim of extending channel bandwidth and improving reconstruction accuracy by leveraging the hybrid carriers and allocating channels in the two-dimensional Fourier domain that yield optimal performance. The scheme enables spectral bandwidth and temporal bandwidth to be traded off, and provides flexibility in selecting demodulation strategies based on the features of the input. We present an in-depth comparison of different systems' performances in various input features under the presence of noise. Simulation results show that the hybrid-modulation strategy offers the best comprehensive performance as compared to the conventional CSP and dual-scan techniques.We proposed a hybrid Fabry-Perot fiber-optic sensor based on the microelectromechanical system (MEMS) technique for measuring temperature and liquid refractive index simultaneously, and we verify the consistency of four sensors in the same batch. The sensor consists of a groove-array structured glass wafer and two silicon wafers, which are connected by double-sided anodic bonding. The three parts form two independent Fabry-Perot cavities for temperature and liquid refractive index sensing, respectively. We randomly selected three sensors in the same batch and conducted temperature and refractive index experiments to establish the sensing equation. The experimental results demonstrate their high consistency with temperature sensitivities of 81.6, 81.8, and 81.4 pm/°C in the range of 10°C to 80°C, and refractive index sensitivities of 1040.11, 1044.24, 1042.91 nm/RIU in the range of 1.333-1.374. The sensors have low cross-sensitivities that are less than 5.86×10-6 RIU/°C and high precisions of 0.047°C, 2.14×10-6RIU, respectively.