硫系玻璃光子晶体光纤研究进展

硫系玻璃与石英玻璃相比具有折射率高(2.0～3.5)、声子能量低(小于350 cm-1)、优良的中远红外透过性能、较宽的组分可调等特性.近年来,硫系玻璃光子晶体光纤作为一种新型中红外光子晶体光纤备受关注.回顾了硫系玻璃光子晶体光纤研究历程,从玻璃组成选择、光纤制备与损耗的降低、传输特性和结构设计、色散特性及应用等方面总...     

硫系玻璃光波导研究进展

硫系玻璃具有超高的非线性折射率、超快的非线性响应、超低的双光子吸收和独特的光敏特性等品质,成为一种新型全光信号处理的理想材料。简介了硫系玻璃材料的基本特性,回顾了硫系玻璃光波导研究历程及其在非线性方面的应用,并对其发展前景进行了展望。     

用于产生超连续谱的硫系光子晶体光纤的色散特性

光子晶体光纤具备的无截止单模、模场面积可调和色散可控的特性,使其在超连续谱的产生中具有独特的优势。超连续谱的产生条件之一,是所使用的光纤须具有高的非线性,而硫系玻璃非线性系数极高,因此利用硫系玻璃光子晶体光纤产生超连续谱的研究备受关注。采用熔融-淬冷法制备Ge23Sb12S65硫系玻璃,并以此为基质设计了用于超连续谱产生的高非线性光子晶体光纤。采用多极法分析光纤孔间距、孔径比d/等对光纤的色散零点位移、色散平坦调控、损耗及模场面积的影响,最终得到当=2m,d/=0.43时,可获得2~4m平坦色散的高非线性光子晶体光纤结构。     

硫系玻璃基掺铒微结构光纤4.5μm波段中红外信号放大特性

为进一步揭示硫系玻璃基掺Er3+微结构光纤作为中红外光纤放大器增益介质的可行性,数值求解了800 nm泵浦波长下Ga5Ge20Sb10S65硫系玻璃基掺Er3+微结构光纤中Er3+离子数速率方程和光功率传输方程组,理论研究了4.5μm波段中红外信号的放大特性。结果显示,Ga5Ge20Sb10S65硫系玻璃基掺Er3+微结构光纤具有较高的信号增益和很宽的增益谱。在50 cm光纤长度上,最大信号增益超过了40 dB,高于30 dB信号增益的放大带宽达到了280 nm(4 420~4 700 nm)。同时,进一步研究分析了4 500 nm波长信号增益与光纤长度、信号输入功率和泵浦功率的关系。研究表明,Ga5Ge20Sb10S65硫系玻璃基掺Er3+微结构光纤是一种理想的可应用于4.5μm波段中红外宽带放大器的增益介质。     

掺铒硫系玻璃光纤的中红外增益特性模拟研究

实验制备了Er3+掺杂质量分数为1%的Ga5Ge20Sb10S65硫系玻璃,测试了其折射率、吸收光谱和荧光光谱,利用Judd-Ofelt和Futchbauer-Ladenburg理论计算了Er3+离子的自发辐射几率、吸收截面和受激发射截面等光谱参数。在综合考虑Er3+离子的交叉弛豫、能量上转换和激发态吸收效应的基础上,应用四能级粒子数速率-光功率传输方程模型,模拟计算了Er3+掺杂Ga5Ge20Sb10S65硫系玻璃光纤的中红外2.74μm波段的增益特性。结果显示,Er3+掺杂硫系玻璃光纤在2.74μm中红外波段具有较高的信号增益和较宽的增益谱,最大增益值和20dB增益带宽分别超过了40dB和200nm,表明其是可用于中红外2.74μm波段宽带放大的理想增益介质。     

硫系基质光波导的非线性应用研究进展

随着集成化程度的不断提高,对非线性光波导制备的各种集成光电子器件的研究成为了当前热点。然而,传统基质材料受自身的非线性特性所限,成为制约光波导器件进一步发展的首要问题。介绍了硫系玻璃材料三阶非线性的研究现状。研究表明,硫系原子在强光作用下容易发生电子云畸变,非线性响应时间可达飞秒数量级,且非线性折射率与金属共价键有着重要的关联。从基质种类、制备工艺和非线性应用领域等方面回顾了硫系基质光波导的研究进展。针对目前研究中存在的问题,提出环保型的基质材料、完善的制备工艺和新型的光波导器件将是未来硫系基质光波导的研究方向。     

Yb3+掺杂锌锗碲酸盐玻璃的热分析、光谱和激光性质

设计了组成为0．70TeO2-(0．20-x)ZnO-xGeO2—0．05La2O3-0．025K2O-0．025Na2O-0．01Yb2O3(摩尔分数x=0,0．05，0．10，0．15和0．20)的碲酸盐激光玻璃，测试了热学性质、吸收光谱、荧光光谱和荧光寿命。计算了Yb^3 离子的吸收截面、受激发射截面、荧光有效线宽等参数。结果表明，组成为0．70TeO2-0．20GeO2-0．05La2O3-0．025K2O-0．025Na2O的玻璃具有优于著名的碲锌钠(TZN)玻璃的热稳定性，高的受激发射截面(1．23pm^2)。长的荧光寿命(0．92ms)和宽的荧光有效线宽(77nm)。通过激光性能评价。最小抽运强度为0．98kW／cm^2，表明掺Yb^3 组份的碲酸盐玻璃是实现高能短脉冲可调谐激光器的理想增益介质。     

Comparative study of spectroscopic properties of Er^3＋／Yb^3＋-codoped tellurite glass and fibres under 980nm excitation＊

A tellurite fibre of TeO_{2}－ZnO－La_{2}O_{3}－Li_{2}O glass codoped with 20000 ppm ytterbium and 5000 ppm erbium was fabricated by the suction casting and rod-in-tube technologies. The absorption spectrum of Er^{3+}/Yb^{3+} -codoped bulk glass has been measured. From the Judd－Ofelt intensity parameters, the spontaneous emission probability and radiative lifetime τ_{rad} of Er^{3+}:{}^{4}I_{13/2}→{}^{4}I_{15/2} transition for the bulk glass have been calculated. The emission fluorescence spectra and lifetimes around 1.5μm, and subsequent upconversion fluorescence in the range of 500－700nm were measured in fibres and compared with those in bulk glass. The changes in amplified spontaneous emission with fibre length and pumping power was also measured. It was found that the emission spectrum from erbium in fibres is almost twice as broad as the corresponding spectrum in bulk glass when pumped at 980nm.     

A low-threshold multiwavelength Brillouin fiber laser with double-frequency spacing based on a small-core fiber

We demonstrate multiwavelength Brillouin fiber lasers (MWBFLs) with double-frequency spacing based on a small-core fiber (SCF) and a standard single-mode fiber (SMF), which have core diameters of 5 and 8.8 μm, respectively. Experimental results show that the SCF-based MWBFL exhibits a higher laser output power and a lower pump threshold. The output powers of the SCF-based MWBFL are > 1.4 times those of the SMF-based MWBFL. Moreover, the threshold power required to generate each channel of the SCF-based MWBFL is 59% that of the SMF-based MWBFL. When the same pump power of 180 mW is injected, the number of laser channels generated for the SCF-based MWBFL is 13, which is twice that generated for the SMF-based MWBFL. In addition, the SCF-based MWBFL exhibits good wavelength tunability from 1535 to 1565 nm and temporal stability over an hour.     

Mixed heavy metal effect on emission properties of Er~(3+)-doped borosilicate glasses

Er3+-doped heavy metal borosilicate glasses were prepared using conventional melting and quenching method. The emission spectra of 4I13/2 → 4I15/2 transition were observed upon excitation at 974 nm and the lifetime of 4I13/2 level of Er3+ was measured. Based on these data, the fluorescence properties of Er3+ are investigated on the emission and gain characteristics at the 1.5 μm bands. In particular, the effect of relative heavy metal content on fluorescence properties is discussed.