Critical dispersion of chirped fiber Bragg grating for eliminating time delay signature of distributed feedback laser chaos

Optical chaos has attracted widespread attention owing to its complex dynamic behaviors.However,the time delay signature(TDS)caused by the external cavity mode reduces the complexity of optical chaos.We propose and numerically demonstrate the critical dispersion of chirped fiber Bragg grating(CFBG)for eliminating the TDS of laser chaos in this work.The critical dispersion,as a function of relaxation frequency and bandwidth of the optical spectrum,is found through extensive dynamics simulations.It is shown that the TDS can be eliminated when the dispersion of CFBG is above this critical dispersion.In addition,the influence of dispersive feedback light and output light from a laser is investigated.These results provide important quantitative guidance for designing chaotic semiconductor lasers without TDS.

Occurrence of Features of Fiber Bragg Grating Spectra Having a Wavelength Corresponding to the Phase Mask Periodicity

The use of a phase mask with 536 nm uniform pitch allowed the fabrication of a fiber Bragg grating for use at a Bragg wavelength of 785 nm. Reflection and transmission features at 1552 nm, twice the Bragg wavelength, associated with the phase mask periodicity were observed. However, when phase mask orders other than ±1 were absent during fabrication the features at 1552 nm were not evident.

The Analysis and Research of Chirped Bragg Fiber GratingTheory on Dispersion Compensation

Based on the general theory of linear Chirped Bragg fiber grating, this paper discusses some parameters including different chirped values and quasi gauss coupling function relating with the reflectivity coefficient dispersion compensation.The result shows that selecting larger chirped value and appropriate qusi guass coupling function can improve the dispersion compensation while ensuring high reflectivity. The concept of "figure of merit" in the microwave field is introduced to quantize the equalizing power of the dispersion compensator.

Fabrication of kW-level chirped and tilted fiber Bragg gratings and filtering of stimulated Raman scattering in high-power CW oscillators

Suppression of stimulated Raman scattering(SRS)by means of chirped and tilted fiber Bragg gratings(CTFBGs)has become a key topic.However,research on high-power systems is still lacking due to two problems.Firstly,after the inscription,there are a large number of hydroxyl compounds and hydrogen molecules in CTFBGs that cause significant heating due to their strong infrared absorption.Secondly,CTFBGs can couple Stokes light from the core to the cladding and the coating,which causes serious heating in the coating of the CTFBG.Aimed at overcoming these bottlenecks,a process that combines constant-low-temperature and variable-high-temperature annealing is used to reduce the thermal slope of the CTFBG.Also,a segmented-corrosion cladding power stripping technology is used on the CTFBG to remove the Stokes light which is coupled to the cladding,which solves the problem of overheating in the coating of the CTFBG.Thereby,a CTFBG with both a kilowatt-level power-carrying load and the ability to suppress SRS in a fiber laser has been developed.Further,we establish a kW-level CW oscillator to test the CTFBG.Experimental results demonstrate that the power-carrying load of the CTFBG is close to 1 kW,the thermal slope is lower than 0.015 ℃/W,and the SRS suppression ratio is nearly 23 dB.

Formation Technologies of Fiber Bragg Gratings

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Code synchronization based on lumped time-delay compensation scheme with a linearly chirped fiber Bragg grating in all-optical analog-to-digital conversion

We propose a novel lumped time-delay compensation scheme for all-optical analog-to-digital conversion based on soliton self-frequency shift and optical interconnection techniques. A linearly chirped fiber Bragg grating is optimally designed and used to compensate for the entire time-delays of the quantized pulses precisely. Simulation results show that the compensated coding pulses are well synchronized with a time difference less than 3.3 ps, which can support a maximum sampling rate of 151.52 GSa/s. The proposed scheme can efficiently reduce the structure complexity and cost of all-optical analog-to-digital conversion compared to the previous schemes with multiple optical time-delay lines.

Strain Multipoint Measurements Based on Chirped Bragg Grating Sensors

In this paper,we propose the novel system of multipoint measurement.The sensors of measurements are chirped Bragg grating and the interrogation of sensors is sub-carrier phase.The wavelength division multiplexing technique is used for addressing a network of FBG sensors and the time-division multiplexing technique is used for multipoint measurements.In the system,the modulation frequency of 200 MHz is adopted.The range of dectetion is from 0 to 900μεand the resolution is 12με. The time of the sensor response is about 1ns.

Chirped Bragg 光纤光栅色散补偿研究

分析ＣｈｉｒｐｅｄＢｒａｇｇ光纤光栅的色散特性，并作一定性分析．利用耦合模方程导出ＣｈｉｒｐｅｄＢｒａｇｇ光纤光栅的反射率方程，从而推导出ＣｈｉｒｐｅｄＢｒａｇｇ光纤光栅的色散计算公式，并用数值分析画出它们的响应曲线．

任意布拉格波长Chirped光栅的写入

提出了一种波长写入范围达30 nm 的Chirped 光栅的构造方法,这种方法只需要一个会聚柱透镜、一个发散柱透镜和相位掩膜板,并且对光纤与相位掩膜板的距离与写入光栅的Bragg

Microwave photonic phase shifter with spectral separation processing using a linear chirped fiber Bragg grating

A stable and broadband microwave photonic phase shifter based on the combined use of a linear chirped fiber Bragg grating and optical single-sideband(OSSB) modulation is proposed and experimentally demonstrated.The quality of the radio frequency(RF) signal is improved by the spectral separation delay processing. The theoretical fundamentals of the scheme are explained and the phase shift can be controlled linearly by the wave?length. of the light source. In the experiment, a full 360° phase shift with a 10 GHz bandwidth can be achieved and tuned dynamically, continuously, and stably.

Wavelength-swept fiber laser based on bidirectional used linear chirped fiber Bragg grating

A wavelength-swept fiber laser is proposed and successfully demonstrated based on a bidirectional used linear chirped fiber Bragg grating(LC-FBG). The wavelength-swept operation principle is based on intracavity pulse stretching and compression. The LC-FBG can introduce equivalent positive and negative dispersion simultaneously, which enables a perfect dispersion matching to obtain wide-bandwidth mode-locking. Experimental results demonstrate a wavelength-swept fiber laser that exhibits a sweep rate of about 5.4 MHz over a 2.1 nm range at a center wavelength of 1550 nm. It has the advantages of simple configuration and perfect dispersion matching in the laser cavity.

Writing Fiber Grating of Different Wavelength Using the Same Phase Mask

Chirped fiber grating was used in dispersion compensator. We tried to use the same phase mask to write fiber grating of different wavelength with two methods to reduce the price of the fiber grating.

Fiber Bragg Grating Sensor Array System Based on Digital Phase Generated Carrier Demodulation and Reference Compensation Method

A novel fiber Bragg grating (FBG) sensor array system based on digital phase generated carrier (PGC) demodulation and reference compensation method is proposed and set up. Experimental results confirm that the digital PGC demodulation can be used for wavelength-division-multiplexed FBG sensor array and the reference compensation method can reduce the environmental interference by approximately 40 dB in the frequency range from 20 Hz to 2 kHz. The minimum detectable wavelength-shift of the sensor system is 1×10?3 pm/Hz1/2.

Chirped Bragg光纤光栅的优化设计与优化指数

根据线性ChirpedBragg光纤光栅的一般原理 ,探讨了不同啁啾系数 ,准高斯耦合函数对Bragg反射光栅的反射率及色散补偿特性的响应。结果表明 :增大啁啾系数以及选取适当的准高斯耦合函数 ,在保证反射率较大的情况下 ,能有效地改善色散补偿特性。通过引入微波领域的“优化指数”这一概念 ,量化了色散补偿器的补偿能力。

Nanostrain Measurement Using Chirped Bragg Grating Fabry-Perot Interferometer

简单 nanostrain 直接水流(DC ) 测量系统基于啁啾的布拉格栅栏 Fabry-Perot (FP ) 结构被介绍。FP 洞，在啁啾的纤维布拉格栅栏(CFBG ) 和纤维结束脸之间形成了，由于 CFBG 介绍非周期的行为。位于穗模式斜坡的激光被用来讯问察觉到的头。当紧张被使用时，光力量参数被分析，为 2.87 的长、短的时期穗模式波长，和敏感有并且 5.48 有分别地被获得。这种配置介绍 70 n 的分辨率。

A Novel Method for the Design of Fiber Gratings

A new weighting technique compatible with phase mask technique and point by point technique is proposed. The design method allows precise weighting of the fiber grating using controlled interference of reflected waves. Based upon the new position weighting method, complex shape of fiber grating spectra can be acquired effectively .

Bragg Grating Formation in B/Ge Codoped Optical Fibers

A 2-cm long Bragg grating with reflectivity of～99.95% in B/Ge codoped optical fiber without hydrogen loading was created by phase-mask method with a pulsed KrF excimer laser at 248 nm. DC and AC components of refractive index change were analyzed by monitoring transmission spectrum evolution during the writing process of fiber Bragg grating. The relations of the evolution of center wavelength and reflectivity with number of pulses were respectively investigated.

变迹啁啾Bragg光纤光栅的矩阵分析

本文用传输矩阵法分析了各种变迹与线性啁啾 Bragg光纤光栅的响应特性 ,构造了各种变迹函数 ,进行了比较 .分析了变迹函数、啁啾系数、折射率变化量以及光栅长度对反射带宽、最大反射率的影响 .找到了最佳变迹函数和量佳啁啾系数 .特例中的数值分析表明 ,补偿 1 0 0 km光纤色散带宽为 1 nm的最佳光栅长度是 1 40 mm,最佳啁啾系数为 0 .0 4 8nm/ cm.

偏振控制法紫外写入Bragg光纤光栅的特性分析

结合目前常用光纤布喇格光栅制作方法 ,详述了一种更加灵活、简单而又有效的制作光纤布喇格光栅的方法 ,即偏振控制法。该方法是基于 :在紫外光s和 p偏振方向诱导而成的两个折射率调制剖面之间形成一个π相移 ,通过改变两个偏振方向上光强比例 ,就能够控制调制量和诱导相移。它的优点是写入的光栅具有多相移和不均匀切趾剖面的特点 。