Proc. SPIE. 9679, AOPC 2015: Optical Fiber Sensors and Applications
KEYWORDS: Signal to noise ratio, Sensors, Interference (communication), Computer simulations, Fiber optics sensors, Data processing, Signal processing, Data conversion, Fiber optic communications, Array processing
The single-channel blind source separation (SCBSS) technique makes great significance in many fields, such as optical fiber communication, sensor detection, image processing and so on. It is a wide range application to realize blind source separation (BSS) from a single optical fiber sensor received data. The performance of many BSS algorithms and signal process methods will be worsened with inaccurate source number estimation. Many excellent algorithms have been proposed to deal with the source number estimation in array signal process which consists of multiple sensors, but they can not be applied directly to the single sensor condition. This paper presents a source number estimation method dealing with the single optical fiber sensor received data. By delay process, this paper converts the single sensor received data to multi-dimension form. And the data covariance matrix is constructed. Then the estimation algorithms used in array signal processing can be utilized. The information theoretic criteria (ITC) based methods, presented by AIC and MDL, Gerschgorin’s disk estimation (GDE) are introduced to estimate the source number of the single optical fiber sensor’s received signal. To improve the performance of these estimation methods at low signal noise ratio (SNR), this paper make a smooth process to the data covariance matrix. By the smooth process, the fluctuation and uncertainty of the eigenvalues of the covariance matrix are reduced. Simulation results prove that ITC base methods can not estimate the source number effectively under colored noise. The GDE method, although gets a poor performance at low SNR, but it is able to accurately estimate the number of sources with colored noise. The experiments also show that the proposed method can be applied to estimate the source number of single sensor received data.
In the 40Gbps high-speed optical fiber communication system, chromatic dispersion of optical signal brings about to
generation of inter-symbol interface which influences the quality of optical fiber communication. In order to solve the
above questions in the 40Gbps differential quarter phase-shift keying (DQPSK) optical fiber communication system, a
new method of chromatic dispersion compensation based on genetic algorithm is proposed according to the
demodulation of DQPSK optical signal and the trait of chromatic dispersion. Result shows that the system’s receiving
sensitivity has been enhanced up to six orders of magnitude.