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A novel high SMSR dual-wavelength erbium-doped fiber laser operating in C-band is proposed and successfully demonstrated. Based on Arrayed-Waveguide Gratings (A WGs) as a comber filter and demultiplexer, the fiber laser retrieve the optical side-mode suppression ratio (SMSR) of 53dB and the output powers of-10.45dBm and-10.20dBm at the wavelengths 1554.87nm and 1555.65nm, respectively. The mode spacing of the dual-wavelength fiber laser is nearly 0.8 nm. The laser can operate in stable narrow-line-width with single- and dual-wavelength output at room temperature.

A model-based adaptive synthetic aperture radar (SAR) image formation algorithm is proposed in this study. A parametric model is used to formulate the received SAR signal, each scatterer can be characterised by a set of its parameters. In the model, the instantaneous slant range is approximated by a polynomial. The parameters of each scatterer are estimated by maximising the cost function, named matching degree indicator. The root-mean-square errors of parameter estimation are close to the Cramer–Rao bounds. The image is formed by mapping the estimated parameters onto the grid formed by iso-range and iso-Doppler lines. The algorithm does not require explicit knowledge of the data collection geometry. Experimental results are given to validate the algorithm.

Fiber coil is a kind of key optical component used in fiber optic gyroscope, and its stability and anti-jamming capability directly influence the performance of the whole fiber optic gyroscope. The quadrupolar winding of fiber coil can restrain thermally induced nonreciprocity obviously at ideal conditions; however, various nonideal factors severely limit the advantage of the quadrupolar winding. A novel method for analyzing the quality of the fiber coil using Raman temperature measurement technology is proposed. The nonreciprocity of fiber coil can be judged by analyzing Raman scattering of fiber coil under conditions of varying temperature, and then the quality of winding a coil can be judged. The corresponding experiments have been done to verify the effect this new method. The results show that this non-destructive method has a guiding role to the fiber coil winding method and technology, and also provide a way for evaluating the quality of the fiber coil.

A theoretical model based on the genetic algorithm is proposed and presented to analyze the gain flatness-characteristics of backward-pumped distributed fiber Raman amplifier (B-DFRA). The relationship between the gain flatness performances with the pump wavelength spacing in B-DFRA is demonstrated theoretically. It is shown that the minimum gain ripple of the B-DFRA can be obtained by optimizing the power of pump source using the genetic algorithm, and the gain spectrum of the B-DFRA which pump wavelengths are arranged in a geometric proportion interval sequence is flatter than the one which pump wavelengths are arranged in an equal interval sequence in the same conditions. Moreover, a design example of an 80-nm bandwidth B-DFRA with the gain ripple of 0.48 dB is presented to verify the accuracy of the theoretical model. This research provides a useful guide to the fabrication of practical B-DFRA.

A simple and effective switchable triple-wavelength Er 3+ -doped fiber laser with narrow-line-width oscillating output is proposed and demonstrated. Only using an arrayed-waveguide grating (AWG) as the comber filter and FBGs as narrow band reflectors of each F-P cavity, a stable simultaneous triple-wavelength oscillation is achieved at room temperature. The output can be switched between single- and triple-wavelength by controlling the LD pump respectively. The side mode suppression ratio and the 3-dB bandwidth of the laser’s outputs are measured to be more than 55dB and less than 10pm. Moreover, the output power stability of the laser has also been measured and analyzed.

Publication in the conference proceedings of EUSIPCO, Bucharest, Romania, 2012