A switchable multi-wavelength Erbium-doped photonic crystal fiber (ED-PCF) ring laser based on a length of
polarization-maintaining photonic crystal fiber(PM-PCF) is presented and demonstrated experimentally. A segment of
ED-PCF is used as linear gain medium in the resonant cavity. Due to the polarization hole burning (PHB) caused by the
PM-PCF and a polarization controller (PC), the laser can operate in stable dual- or triple- wavelength modes at room
temperature. The optical signal-to-noise ratio (OSNR) of the laser without any wavelength-selective components is
greater than 30 dB. The amplitude variations of lasing peaks in ten minutes are less than 0.26dB for two different
operating modes.
A red-sensitive photopolymer material sensitized by azure II is fabricated and its holographic storage characteristics are
studied. The experimental results show that this kind of material has high diffraction efficiency (the maximum value
56%), high exposure sensitivity (5.2×10-3 cm2/mJ) and large refractive index modulation (1.6×10-3). The analog image
generated by a spatial light modulator (SLM) is stored in this medium, the transmission and reconstruction images have a
good fidelity. It shows that this photopolymer material has the potential for high-density volume holographic storage.
The dynamic theoretical model of photochemical and hologram formation in holographic photopolymer is established, and the dynamic development process of holographic storage in the photopolymer is discussed with the model. A holographic photopolymer sensitized by erythrosine B is prepared, which is composed of acrylamide as monomer, ployvinylalcohol as binder, triethanolamine as initiator. The influence of the exposure intensity on holographic storage characteristics is analyzed. The experimental data of transmittance and diffraction efficiency of the fabricated photopolymer with different exposure intensities are obtained. By means of fitting the experimental data of transmittance and diffraction efficiency as a function of time with five exposure intensities at a wavelength of 514nm, the variation of photochemistry and photopolymerization diffusion dynamic parameters such as the molar-absorption coefficient ε, quantum yield Φ, photobleaching coefficient kp, polymerization rate k0 and diffusion time constant τD is presented. The research results show that as the exposure intensity increases, so do also ε, kp and k0, but Φ becomes smaller. And τD has no obvious changes except the sample is overexposed. This material has the characteristics of longer diffusion times for the monomer to travel from the unexposed to the exposed zones than that in the case of other polymeric materials.
In this thesis, two kinds of photopolymer films sensitized by azure I and azure II respectively are fabricated and their important holographic characteristics including the sensitive spectral range of films, transmittance, diffraction efficiency (DE), the thickness of photopolymer films and refractive index modulation are compared. It can be found that the photopolymer film sensitized by azure II(sample 2) has more obvious advantages than the photopolymer film sensitized by azure I (sample 1)on the holographic characteristics from the absorption intensity and the optimum concentration of dye and the inner uniformity of sample to the photochemical reaction velocity and the optimum medium thickness. On the contrary, sample 1 has higher maximum diffraction efficiency and refractive index modulation than sample 2.
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