Complex coupling agents system with two kinds of functional, crosslinked groups(-NH2 and -C=C-) are employed for the
first time to generate crosslinked structures in the formation of inorganic-organic interpenetrating polymer networks(IPNs)
composed of methyl methacrylate-co-maleic anhydride copolymer and silica polymer formed by hydrolysis of
tetraethoxysilane via radical polymerization and sol-gel method of two networks. The polymerization process, morphology
and the mechanical properties of hybrids are studied by FTIR, TEM, transparency, TG-DTA and stress-strain curve detection.
The results indicate that the component ratio has effect to the transparent and mechanical properties of hybrids. The FT-IR
detection results proved the formation of crosslink structures between two networks. The TEM observation results indicate
that the introduction of covalent bond can control the phase separation of hybrid within 20nm and thus obtain hybrids with
higher transparency(above 85%). The mechanical property detection results show that thermal resistance, elastic modulus
and tensile strength are all improved by the interpenetration of inorganic phase into hybrid compared with pure organic
A new linear cavity multi-wavelength erbium-doped fibre laser with enhanced signal-to-noise ratio characteristics is demonstrated. The laser system is developed by two steps from a conventional ring cavity configuration which consists of a frequency-shifted cavity and single multi-wavelength filters. Firstly, the noises characteristic is improved about 2.8 dB on an average with the inset of a dual-pass Mach-Zender interferometer and shifting the station of output coupler However, the output power is suppressed about 1.5 dB on an average by the change. Next, the noises characteristic is further improved by about 4.3dB against the conventional ring cavity configuration and the output power is increased by about 1.8 dB by utilizing a special Bragg grating array replacing the F-P filter to compose a linear cavity configuration.. The emitting range with output flatness better than 3dB covers 20nm wavelengths from 1540 to 1560 nm, with line spacing of 0.8nm and average output power of 0.8dBm.The linear cavity multi-wavelength erbium-doped fibre laser with high signal-to noise ratio can be useful in a wavelength division multiplexing transmission system.
A novel L-band multi-wavelength erbium-doped fibre ring laser was proposed and studied by numerical method. The numerical model was developed based on a C-band EDFA and the propagation and rate equations of homogeneous broaden in two levels medium. In this L-band model, the excited state absorption was included during computing. The flat multi-wavelength laser in L-band was achieved by lengthening the erbium-doped fibre, and utilizing detrimental backward amplified spontaneous emission as a secondary pump power. The laser emitting spectral region was shifted, to prevent the mode competing at room temperature. This kind of laser can be useful in a wavelength division multiplexing transmission (WDM) system.