In-fiber grating systems for pulse compression and complete dispersion compensation

1995 ◽  
Author(s):  
J.A.R. Williams
Keyword(s):  
Pulse Compression ◽  
Dispersion Compensation ◽  
Fiber Grating

Dispersion Compensation of Thin-Clad Chirped Long-Period Fiber Grating

2009 ◽  
Vol 29 (4) ◽  
pp. 879-883
Author(s):  
顾铮天 Gu Zhengtian ◽  
蒋秀丽 Jiang Xiuli
Keyword(s):  
Dispersion Compensation ◽  
Fiber Grating ◽  
Long Period Fiber Grating ◽  
Long Period ◽  
Period Fiber Grating

Research on Application of Tunable Dispersion Compensation Technology in Optical Fiber Communication Systems

2013 ◽  
Vol 401-403 ◽  
pp. 1956-1959
Author(s):  
Wen Xuan Gai
Keyword(s):  
Communication Systems ◽  
Dispersion Compensation ◽  
Optical Fiber Communication ◽  
Fiber Grating ◽  
Basic Principles ◽  
Fiber Communication ◽  
Future Direction ◽  
Chirped Fiber Grating ◽  
Research On Application ◽  
Communications System

For high bit-rate optical communications system, the changes in temperature or power fluctuations are due to the dispersion of the dispersion tolerance than the system. Therefore, the dispersion compensation unit must have the functionality to adapt to the dynamic generation of tunable optical communication network development. This article describes several dynamic tunable compensation techniques and the basic principles of the performance characteristics of the situation at home and abroad, including the chirped fiber grating method, the virtual image phased array method, GT interferometer method, the array method and the planar waveguide grating method, and a brief discussion of tunable dispersion compensation technology in the future direction of development.

Excitation series design and pulse compression synthesis for high-resolution Lamb wave inspection

2018 ◽  
Vol 18 (5-6) ◽  
pp. 1464-1478
Author(s):  
Jiadong Hua ◽  
Liang Zeng ◽  
Jing Lin ◽  
Liping Huang
Keyword(s):  
Lamb Wave ◽  
Pulse Compression ◽  
Lamb Waves ◽  
Dispersion Compensation ◽  
Synthesis Method ◽  
Side Lobe ◽  
Main Lobe ◽  
Window Functions ◽  
Windowing Technique ◽  
Lobe Width

Lamb wave pulse compression is a promising technique for ultrasonic nondestructive evaluation and structural health monitoring, in which the excitation waveform is designed to exhibit attractive auto-correlation characteristics including short main-lobe width and small side-lobe amplitude. However, narrowing main-lobe will increase side-lobe amplitude, and vice versa. Conventional time windowing technique is a balance between main-lobe width and side-lobe amplitude. An improvement over time windowing is proposed using pulse compression synthesis method. In this method, a series of excitation waveforms are used to actuate Lamb waves, each response is processed by pulse compression, and all the compression signals are summed together. The excitation series are constructed as linear chirps weighted with different combinations of rectangular and Hanning window functions. The selection of the combination coefficients is optimized to ensure best signal summation. The effectiveness of the proposed method is demonstrated by an experiment, and the robustness to inaccuracy in dispersion compensation is also evaluated. Application of the proposed method for damage detection is demonstrated by a further experiment.

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