Point-by-point inscription of apodized fiber Bragg gratings

Optical spectral pulse shaping by combining two oppositely chirped fiber Bragg grating

In this letter we present a new technique for pulse shaping. The desired pulse is shaped by two apodized chirped fiber Bragg gratings which dispersions are adjusted to be cancelled. This technique exploits the well-known property of linearly-chirped gratings, in which the apodization (amplitude) grating profile maps its spectral response. This technique presents inherent advantages of chirped fiber Bragg gratings and direct design in frequency domain.

Resonant THz sensor for paper quality monitoring using THz fiber Bragg gratings

We report fabrication of THz fiber Bragg gratings (TFBG) using CO2 laser inscription on subwavelength step-index polymer fibers. A fiber Bragg grating with 48 periods features a ~4 GHz-wide stop band and ~15 dB transmission loss in the middle of a stop band. The potential of such gratings in design of resonant sensor for monitoring of paper quality is demonstrated. Experimental spectral sensitivity of the TFBG-based paper thickness sensor was found to be ~ -0.67 GHz / 10 um. A 3D electromagnetic model of a Bragg grating was used to explain experimental findings.

Single-mode sapphire fiber Bragg grating

We present here the inscription of single-mode waveguides with Bragg gratings in sapphire. The waveguide Bragg gratings have a novel multi-layer depressed cladding design in the 1550 nm telecommunications waveband. The Bragg gratings have a narrow bandwidth (<0.5 nm) and have survived annealing at 1000°C. The structures are inscribed with femtosecond laser direct writing, using adaptive beam shaping with a non-immersion objective. A single-mode sapphire fiber Bragg grating is created by writing a waveguide with a Bragg grating within a 425 μm diameter sapphire optical fiber, providing signific…

Tailoring inhomogeneous $\mathcal{PT}$-symmetric fiber Bragg grating spectra

The unique spectral behavior exhibited by a class of non-uniform Bragg periodic structures, namely chirped and apodized fiber Bragg gratings (FBGs) influenced by parity and time reversal ($\mathcal{PT}$) symmetry, is presented. The interplay between the $\mathcal{PT}$-symmetry and nonuniformities brings exceptional functionalities in the broken $\mathcal{PT}$-symmetric phase such as wavelength selective amplification and single-mode lasing for a wide range of variations in gain-loss. We observe that the device is no more passive and it undergoes a series of transitions from asymmetric reflecti…

毫米尺度复杂调制集成布拉格光栅的高效仿真：基于分层局部周期本征模展开

Efficient simulation of millimeter-scale complex-modulated integrated Bragg gratings via hierarchical locally periodic eigenmode expansion

提出HLP-EME框架，通过分层局部周期本征模展开高效仿真毫米尺度复杂调制集成布拉格光栅，加速比超三个数量级，并扩展至弯曲波导，为长复杂光栅器件设计提供高效工具。

All-fiber laser pump reflector based on a fs-written VBG

We report on the writing of chirped volume Bragg gratings using 400 nm femtosecond pulses and the phase-mask inscription technique in the pure silica inner cladding of the gain fiber. The usefulness of such fiber component is demonstrated as a pump reflector in a cladding-pumped all-fiber laser. A reflectivity of 53% for the residual pump power guided in the cladding of the highly multimode 125 microns fiber is achieved, allowing for significant pump recycling in the fiber laser cavity which therefore optimizes the overall laser performances. As proof of concept, adding this pump reflector at …

Photo-Writable Sulfide Glasses Used to Fabricate Core-Clad Fiber Doped with Pr$^{3+}$ for Mid-IR Luminescence

With the ultimate goal of developing rare-earth doped chalcogenide fiber fabrication for sensing, amplification, and laser applications, a core/clad germanium-gallium sulfide fiber doped with Pr$^{3+}$ has been fabricated. The compositions of the core and the clad were selected to ensure the positive $Δ$n by adding CdI$_2$ and CsCl, respectively, in the GeS$_2$ -Ga$_2$S$_3$ matrix. The choice of these compositions was also justified from experimental parameters, including characteristic temperatures and viscosity. Moreover, the permanent photo writability of the sulfide glass family by a femto…

用于量子点单光子产生的紧凑型啁啾光纤布拉格光栅

Compact Chirped Fiber Bragg Gratings for Single-Photon Generation from Quantum Dots

本研究提出一种基于啁啾光纤布拉格光栅的紧凑模块，用于高效激发量子点产生单光子，克服现有方法的体积和稳定性问题。

用于天体光子学的连续波紫外激光与飞秒红外激光刻写的光纤布拉格光栅滤波器损耗对比分析

Comparative analysis of fiber Bragg grating filter losses inscribed by continuous wave UV and femtosecond-IR lasers for astrophotonics

本研究对比了连续波紫外激光与飞秒红外激光刻写的光纤布拉格光栅滤波器损耗，探索降低高NA光纤插入损耗的方法，提出可减少熔接点数量50%的紧凑型桥接光纤方案，两种滤波器平台均适用于天体光子系统。