期刊文献+
共找到710篇文章
< 1 2 36 >
每页显示 20 50 100
Stable single longitudinal mode erbium-doped silica fiber laser based on an asymmetric linear three-cavity structure 被引量:2
1
作者 冯亭 延凤平 +4 位作者 李琦 彭万敬 冯素春 谭思宇 温晓东 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第1期268-272,共5页
We present a stable linear-cavity single longitudinal mode (SLM) erbium-doped silica fiber laser. It consists of four fiber Bragg gratings (FBGs) directly written in a section of photosensitive erbium-doped fiber ... We present a stable linear-cavity single longitudinal mode (SLM) erbium-doped silica fiber laser. It consists of four fiber Bragg gratings (FBGs) directly written in a section of photosensitive erbium-doped fiber (EDF) to form an asymmetric three-cavity structure. The stable SLM operation at a wavelength of 1545.112 nm with a 3-dB bandwidth of 0.012 nm and an optical signal-to-noise ratio (OSNR) of about 60 dB is verified experimentally. Under laboratory conditions, the performance of a power fluctuation of less than 0.05 dB observed from the power meter for 6 h and a wavelength variation of less than 0.01 nm obtained from the optical spectrum analyzer (OSA) for about 1.5 h are demonstrated. The gain fiber length is no longer limited to only several centimeters for SLM operation because of the excellent mode-selecting ability of the asymmetric three-cavity structure. The proposed scheme provides a simple and cost-effective approach to realizing a stable SLM fiber laser. 展开更多
关键词 asymmetric three-cavity structure single longitudinal mode erbium-doped fiber laser linear cavity
在线阅读 下载PDF
Experimental investigation on chaos generation in erbium-doped fiber single-ring lasers 被引量:1
2
作者 常锋 冯玉玲 +3 位作者 姚治海 范健 宋远超 赵玉柱 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第10期155-158,共4页
In this paper,the chaotic behaviors in an erbium-doped fiber(EDF) single-ring laser(EDFSRL) are investigated experimentally by using the loss modulation method.An electro-optic modulator(EOM) made of LiNbO 3 cry... In this paper,the chaotic behaviors in an erbium-doped fiber(EDF) single-ring laser(EDFSRL) are investigated experimentally by using the loss modulation method.An electro-optic modulator(EOM) made of LiNbO 3 crystal is added to the system.Thus,by changing the modulation voltage and the modulation frequency of the EOM,the freedom of the EDFSRL system is increased.The chaotic characteristics of the system are studied by observing the time series and the power spectra.The experimental results indicate that the erbium-doped fiber single-ring laser system can enter into chaos states through period-doubling bifurcation and intermittency routes. 展开更多
关键词 erbium-doped fiber single-ring lasers electro-optic modulator chaos generation power spectrum
在线阅读 下载PDF
A novel 3-stage structure for a low-noise, high-gain and gain-flattened L-band erbium doped fiber amplifier
3
作者 强则煊 何赛灵 +1 位作者 张徐亮 沈林放 《Journal of Zhejiang University Science》 CSCD 2004年第9期1130-1134,共5页
The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from... The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from the first section of the EDF (erbium-doped fiber) and the backward ASE from the third section of the EDF (both serve as the secondary pump sources of energy) to pump the second EDF. To improve the pump efficiency, the power of the pump is split into two parts (with a ratio of e.g. 2:7). The characteristics of this L-band EDFA are studied on the basis of the Giles Model with ASE. 展开更多
关键词 erbium doped fiber amplifier Three-stage Pump L-BAND fiber optical communication
在线阅读 下载PDF
Bidirectional Erbium Doped Fiber Amplifiers
4
作者 Zhong, C. Peixuan, J. +1 位作者 Ling, L. Peida, Y. 《High Technology Letters》 EI CAS 1995年第1期66-70,共5页
Bidirectional EDFAs(Bi-EDFAs)featuring bidirectional signal input are theoreticallystudied.Gain and noise performances of Bi-EDFAs are analysed numerically and comparedwith that of other optical amplifiers.Application... Bidirectional EDFAs(Bi-EDFAs)featuring bidirectional signal input are theoreticallystudied.Gain and noise performances of Bi-EDFAs are analysed numerically and comparedwith that of other optical amplifiers.Applications of Bi-EDFAs in fiber networks and otherfields are considered. 展开更多
关键词 erbium doped fiber amplifiers ASE Bidirectional optical amplifiers
在线阅读 下载PDF
Analysis of New Q-switched Erbium Doped Fiber Laser Based on Fiber Grating Loop Mirror
5
作者 CAIHai-wen KIMInsooS 《Semiconductor Photonics and Technology》 CAS 2001年第4期202-204,208,共4页
An all fiber wavelength selective Q switching modulator based on fiber grating loop mirror is proposed. A newly configured Q switched erbium doped fiber laser using this all fiber modulator is numerically analyzed tak... An all fiber wavelength selective Q switching modulator based on fiber grating loop mirror is proposed. A newly configured Q switched erbium doped fiber laser using this all fiber modulator is numerically analyzed taking into account the effects of the spontaneous emission. 展开更多
关键词 Q switch erbium doped fiber laser fiber grating
在线阅读 下载PDF
Erbium Doped Fiber Laser and Amplifier
6
作者 Belloui Bouzid 《Optics and Photonics Journal》 2014年第7期189-193,共5页
In this paper, new configuration is proposed, investigated and analyzed. Fiber laser and fiber amplifier are merged in one configuration which called Erbium Doped Fiber Laser and Amplifier (EDFLA) or integrating EDFL ... In this paper, new configuration is proposed, investigated and analyzed. Fiber laser and fiber amplifier are merged in one configuration which called Erbium Doped Fiber Laser and Amplifier (EDFLA) or integrating EDFL and EDFA in one design. The configuration has three main outputs;one for laser, second for amplifier and the third it can be used for on/off output. A surprising phenomenon was remarked during the operation of this configuration. The amplification is abolished during the lasing state and appeared again if the lasing is stopped or the switch is off. The difference between outputs with the lasing and without lasing has 30 dB EDFA gain value;it is a good sign that this optical configuration can be used as an on/off integrated optical device for fiber laser. 展开更多
关键词 erbium doped fiber AMPLIFIER erbium doped fiber LASER LASING Amplification
在线阅读 下载PDF
Passively Q-Switched Erbium-Doped Fiber Laser with TiSe<sub>2</sub>as Saturable Absorber
7
作者 Zhifeng Hong Ying Liu +4 位作者 Fuhao Yang Xiaojuan Liu Huanian Zhang Liping Guo Xiaolu Ge 《Optics and Photonics Journal》 2021年第11期251-263,共13页
<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i&l... <span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">nanosheets</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> prepared by means of ultrasound-assisted liquid </span><span style="font-family:Verdana;font-size:12px;">phase exfoliation (LPE)</span><span style="font-family:Verdana;font-size:12px;"> and the </span><span style="font-family:Verdana;font-size:12px;">nonlinear </span><span style="font-family:Verdana;font-size:12px;">saturable absorption</span><span style="font-family:Verdana;font-size:12px;"> properties</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were experimentally</span><span style="font-family:Verdana;font-size:12px;"> investigated. The modulation depth, saturation intensity and nonsaturable absorbance</span><span style="font-family:Verdana;font-size:12px;"> of the prepared </span><span style="font-family:Verdana;font-size:12px;">1T-TiSe</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">SA </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">1</span><span style="font-family:Verdana;font-size:12px;">5.7</span><span style="font-family:Verdana;font-size:12px;">%,</span><span style="font-family:Verdana;font-size:12px;"> 1.28 M</span><span style="font-family:Verdana;font-size:12px;">W/cm</span><sup><span style="font-family:Verdana;font-size:12px;vertical-align:super;">2</span></sup><span style="font-family:Verdana;font-size:12px;"> and 8.</span><span style="font-family:Verdana;font-size:12px;">2</span><span style="font-family:Verdana;font-size:12px;">%, </span><span style="font-family:Verdana;font-size:12px;">respectively</span><span style="font-family:Verdana;font-size:12px;">. Taking advantage of the saturable absorption properties of </span><span style="font-family:Verdana;font-size:12px;">T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;">-based SA, a passively Q-switched erbium-doped fiber (EDF) laser was</span><span style="font-family:Verdana;font-size:12px;"> systematically demonstrated</span><span style="font-family:Verdana;font-size:12px;">. The pulse repetition rates varied from 24.50 kHz up to 73.79 kHz with the increasing pump power. The obtained shortest pulse width was 1.31 </span><span style="font-family:Verdana;font-size:12px;">μ</span><span style="font-family:Verdana;font-size:12px;">s with pulse energy of 79.28 nJ. The </span><span style="font-family:Verdana;font-size:12px;">system presented merits of low-cost SA preparation, system compactness,</span><span style="font-family:Verdana;font-size:12px;"> superb stability and high competition.</span> 展开更多
关键词 Q-Switched fiber Laser 1T-Phase Titanium Diselenide (1T-TiSe2) Saturable Absorber (SA) erbium-doped fiber (edf) Two-Dimensional (2D) Materials
在线阅读 下载PDF
Modeling and Experiments of the Gain and Noise Figure for an Irradiated Erbium-Ytterbium Co-Doped Fiber Amplifier
8
作者 Sherif S. Nafee Taymour A. Hamdalla 《Journal of Analytical Sciences, Methods and Instrumentation》 2014年第2期53-61,共9页
It is crucial to study the effect of radiation on the fiber amplifier devices. In the present paper, the Erbium-ytterbium co-doped fiber amplifier (EYDFA) has been irradiated by a neutron beam of different doses for v... It is crucial to study the effect of radiation on the fiber amplifier devices. In the present paper, the Erbium-ytterbium co-doped fiber amplifier (EYDFA) has been irradiated by a neutron beam of different doses for various exposure times from an Am-241/Be-9 neutron source. The gain and noise figure of the EYDFA have been calculated theoretically and recorded after and before the irradiation to test its performance under the effect of irradiation. In order to show the enhancement in the gain of the fiber amplifier devices, a comparison between the gain of the irradiated EYDFA and Erbium doped Fiber amplifier (EDFA) has been carried out. The calculated results by the proposed model are in good agreement with the experimental ones. It indicates that the gain of EYDFA deteriorates after being irradiated by a neutron dose. Moreover, the gain of irradiated EYDFA has been reduced to 13.8 dB at a dose of 720 Gy. 展开更多
关键词 erbium-Ytterbium Co-doped fiber Amplifier Americium/Beryllium-Neutron Source GAIN Deterioration
在线阅读 下载PDF
Passively Q-Switched Erbium-Doped Fiber Laser Based on GeSe Saturable Absorber
9
作者 Ying Liu Zhifeng Hong +2 位作者 Xiaojuan Liu Ran Zhang Shiliang Yin 《Optics and Photonics Journal》 2021年第4期89-103,共15页
GeSe nanosheets were prepared by ultrasonic-assisted liquid<span><span><span style="font-family:;" "=""> </span></span></span><span><span><sp... GeSe nanosheets were prepared by ultrasonic-assisted liquid<span><span><span style="font-family:;" "=""> </span></span></span><span><span><span><span style="font-family:Verdana;">phase exfoliation (LPE), and the nonlinear saturated absorption performance was experimentally studied. The modulation depth and saturation intensity of the prepared GeSe saturable absorber (SA) were 15% and 1.44 MW/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">, respectively. Us</span><span style="font-family:Verdana;">ing the saturated absorption characteristics of GeSe SA, a passively Q-switched </span><span style="font-family:Verdana;">erbium-doped fiber laser was systematically demonstrated. As the pump</span><span style="font-family:Verdana;"> power increases, the pulse repetition frequency increases from 22.8 kHz to 77.59 </span><span style="font-family:Verdana;">kHz. The shortest pulse duration is 1.51 μs, and the corresponding pulse</span><span style="font-family:Verdana;"> energy is 46.14 nJ. Experimental results show that GeSe nanosheets can be used as high-efficiency SA in fiber lasers. Our results will provide a useful reference for demonstrating pulsed fiber lasers based on GeSe equipment.</span></span></span></span> 展开更多
关键词 GeSe Nanosheets GeSe Saturable Absorber Passively Q-Switched erbium-doped fiber Laser
在线阅读 下载PDF
EDFA的原理分析及应用探究
10
作者 王淼 殷佳帆 +1 位作者 陈越轩 谢东辰 《数字通信世界》 2024年第5期75-76,83,共3页
互联网信息技术迅猛发展,传统的光电转换技术一定程度上已无法满足现代电信传输的要求。掺铒光纤放大器(EDFA)在泵浦光的作用下可以直接放大光信号,适用于现代光纤通信。该文分析了EDFA的基本原理,探究了EDFA技术的应用及发展趋势。
关键词 现代电信传输 掺铒光纤放大器 edfA 光纤通信
在线阅读 下载PDF
卫星光通信中空间辐射对EDFA性能的影响分析 被引量:13
11
作者 马晶 李密 +6 位作者 谭立英 于思源 周彦平 俞建杰 车驰 常国龙 卢春莲 《宇航学报》 EI CAS CSCD 北大核心 2009年第1期250-254,共5页
由于光纤类器件对于辐射十分敏感,考虑到卫星光通信特定的辐射环境,要想采用地面已非常成熟的外调制技术,必须分析外调制技术中的核心器件EDFA在其中的可行性。采用60Co作为辐射源,国内首次对ED-FA及其内部重要组件隔离器和WDM耦合器进... 由于光纤类器件对于辐射十分敏感,考虑到卫星光通信特定的辐射环境,要想采用地面已非常成熟的外调制技术,必须分析外调制技术中的核心器件EDFA在其中的可行性。采用60Co作为辐射源,国内首次对ED-FA及其内部重要组件隔离器和WDM耦合器进行了高剂量轨道和低剂量轨道辐照模拟实验,实验结果表明在总剂量为5krad的低剂量辐照情况下,EDFA在-2dBm的输入时,输出功率由辐照前的14.3dBm下降到14dBm,其它各组件的性能变化不是很大,可以直接使用,而在总剂量为1000krad的高剂量辐照情况下,输出功率下降到-25.3dBm,耦合器也产生了大约8dB的损耗,由于其性能下降明显,若在此种环境下使用,需考虑做空间辐射防护。 展开更多
关键词 掺铒光纤放大器 伽马辐射 空间环境 卫星光通信
在线阅读 下载PDF
光纤布喇格光栅作为增益均衡器的掺铒光纤EDFA放大器(英文) 被引量:4
12
作者 池灏 赵焕东 +4 位作者 曾庆济 肖石林 姜淳 王建新 黄俊 《光子学报》 EI CAS CSCD 北大核心 2002年第10期1248-1251,共4页
采用平均反转率模型分析了带光纤布喇格光栅的增益平坦掺铒光纤放大器 ,其输出增益可由一组耦合超越方程描述 ,而非耦合微分方程 ,同时讨论了用于增益平坦的布喇格光栅的最佳位置设计 作为增益建模和最佳设计实例 ,对于输入功率 0 .5m... 采用平均反转率模型分析了带光纤布喇格光栅的增益平坦掺铒光纤放大器 ,其输出增益可由一组耦合超越方程描述 ,而非耦合微分方程 ,同时讨论了用于增益平坦的布喇格光栅的最佳位置设计 作为增益建模和最佳设计实例 ,对于输入功率 0 .5mW位于 1 5 4 5~ 1 5 5 2nm的 8个波长信道 ,得到的输出增益不平坦度小于 0 .0 5dB . 展开更多
关键词 增益均衡器 掺铒光纤放大器 edfA 建模 光纤布喇格光栅
在线阅读 下载PDF
Gain and Noise Properties of Bidirectional EDFAs 被引量:1
13
作者 毛庆和 王劲松 +2 位作者 于虹 孙小菡 张明德 《Journal of Southeast University(English Edition)》 EI CAS 1998年第2期34-39,共6页
The rate equation model is setup for the signal gain, pump absorption and output noise spectrum of bidirectional EDFA (Bi EDFA) including numbers of signals, pumps of arbitrary direction, amplified spontaneous emissi... The rate equation model is setup for the signal gain, pump absorption and output noise spectrum of bidirectional EDFA (Bi EDFA) including numbers of signals, pumps of arbitrary direction, amplified spontaneous emission (ASE) and inherent loss. The influence of erbium doped fiber length, input signal power, pump style and pump power on the gain characteristics of Bi EDFA is analyzed. Forward and backward noise figure for different pump style versus bidirectional input signal power is investigated. 展开更多
关键词 erbium doped fiber bidirectional amplifier GAIN noise figure
在线阅读 下载PDF
EDFA对基孤子脉冲进行压缩与放大的数值研究 被引量:4
14
作者 陈海涛 吴正茂 +2 位作者 范云霞 姜广东 夏光琼 《激光技术》 CAS CSCD 北大核心 2006年第2期202-205,共4页
从描述光脉冲在掺铒光纤放大器(EDFA)中传输的非线性薛定谔方程出发,对基孤子脉冲在EDFA中的压缩与放大进行了数值研究,并对孤子脉冲在其中的压缩提出优化方案。结果表明,通过合理地选择EDFA的参数,可使无啁啾的基孤子脉冲实现绝热压缩... 从描述光脉冲在掺铒光纤放大器(EDFA)中传输的非线性薛定谔方程出发,对基孤子脉冲在EDFA中的压缩与放大进行了数值研究,并对孤子脉冲在其中的压缩提出优化方案。结果表明,通过合理地选择EDFA的参数,可使无啁啾的基孤子脉冲实现绝热压缩和放大;对具有初始啁啾的基孤子脉冲,压缩过程将不再满足绝热条件;对于正啁啾的基孤子脉冲,可得到较好的压缩与放大;而对于负啁啾的基孤子脉冲,压缩效果却较差。 展开更多
关键词 非线性光学 掺铒光纤放大器 基孤子脉冲 绝热压缩 压缩因子 基座能量比
在线阅读 下载PDF
EDFA增益瞬态控制研究的最新进展 被引量:10
15
作者 占生宝 丁健 《激光技术》 CAS CSCD 北大核心 2015年第5期706-711,共6页
针对当前光分组与线路节点光放大高稳定性需求,依据电、光两种主流控制方案,阐明了掺Er3+光纤放大器(EDFA)带微调和无微调情况下,基于电的自动增益控制机理。综述了EDFA增益瞬态控制研究的最新进展。分析了各种增益控制方案的具体控制... 针对当前光分组与线路节点光放大高稳定性需求,依据电、光两种主流控制方案,阐明了掺Er3+光纤放大器(EDFA)带微调和无微调情况下,基于电的自动增益控制机理。综述了EDFA增益瞬态控制研究的最新进展。分析了各种增益控制方案的具体控制过程。呈现了这些控制方法所取得的阶段性成果。 展开更多
关键词 光通信 掺Er^3+光纤放大器 波分复用 增益瞬态 自动增益控制
在线阅读 下载PDF
铒纤长度对EDFA增益斜率影响的实验研究和数值模拟 被引量:5
16
作者 赵兰兰 朱益清 《光学技术》 CAS CSCD 北大核心 2010年第5期749-752,共4页
基于掺铒光纤放大器(EDFA)的增益斜率随着铒纤(EDF)长度变化的实验现象,对EDFA的增益斜率进行了分析,研究了不同EDF长度对EDFA的增益斜率的影响,从理论上对实验现象进行了解释。然后用OptiSystem模拟不同EDF长度下的EDFA增益谱,与实验... 基于掺铒光纤放大器(EDFA)的增益斜率随着铒纤(EDF)长度变化的实验现象,对EDFA的增益斜率进行了分析,研究了不同EDF长度对EDFA的增益斜率的影响,从理论上对实验现象进行了解释。然后用OptiSystem模拟不同EDF长度下的EDFA增益谱,与实验室增益斜率数据相一致,得出了用EDF的长度来控制EDFA增益斜率的方法。 展开更多
关键词 掺铒光纤放大器 增益斜率 光纤长度 OPTISYSTEM
原文传递
混合拉曼/EDFA放大器及其在DWDM中的应用 被引量:3
17
作者 于娟 林洪榕 沈晓强 《电讯技术》 北大核心 2002年第5期45-50,共6页
本文综述了混合拉曼 掺饵光纤放大器 (HFA)的工作原理、结构和特点 ,介绍了 4类HFA基本结构及其实验结果 ,并通过介绍近年来各类HFA在密集波分复用 (DWDM)系统中的应用表明了HFA在带宽。
关键词 拉曼/edfA放大器 DWDM 光纤通信 密集波分复用 掺饵光纤放大器
在线阅读 下载PDF
采用EDFA的空间光通信系统模型 被引量:4
18
作者 葛林 邱昆 阳树棕 《电子科技大学学报》 EI CAS CSCD 北大核心 1998年第3期261-264,共4页
介绍了空间光通信系统的基本结构,并根据长距离星间链接的特点,提出一种采用EDFA技术的光发射机和光接收机模型,以实现大功率激光输出和接收机的高灵敏度。提出一个622Mb/s系统的功率预算方案,通过分析,证明该方案是能... 介绍了空间光通信系统的基本结构,并根据长距离星间链接的特点,提出一种采用EDFA技术的光发射机和光接收机模型,以实现大功率激光输出和接收机的高灵敏度。提出一个622Mb/s系统的功率预算方案,通过分析,证明该方案是能够实现的。 展开更多
关键词 空间光通信 激光器 掺铒光纤放大器 功率预算
在线阅读 下载PDF
双向EDFA对长距离光纤时间传递影响研究 被引量:2
19
作者 程清明 张宝富 +2 位作者 卢麟 经继松 吴传信 《光通信技术》 CSCD 北大核心 2012年第3期50-52,共3页
设计实现了用于光纤时间传递系统的BEDFA,理论分析了该BEDFA对长距离光纤时间传递性能的影响并进行了相应仿真,得出每增加一个BEDFA时间系统精度降低50ps、稳定度降低5×10-11/s(-25dBm接收光功率和典型参数)的结论。利用环回法时... 设计实现了用于光纤时间传递系统的BEDFA,理论分析了该BEDFA对长距离光纤时间传递性能的影响并进行了相应仿真,得出每增加一个BEDFA时间系统精度降低50ps、稳定度降低5×10-11/s(-25dBm接收光功率和典型参数)的结论。利用环回法时间传递样机设计相应实验对理论进行了验证。 展开更多
关键词 光纤授时 双向掺铒光纤放大器 环回法
在线阅读 下载PDF
泵浦功率对C波段EDFA增益斜率的影响 被引量:3
20
作者 赵兰兰 朱益清 《江南大学学报(自然科学版)》 CAS 2010年第3期289-291,共3页
基于C波段掺铒光纤放大器(EDFA)的增益斜率随泵浦功率变化的实验现象,研究了不同泵浦功率对增益斜率的影响,从理论上对实验现象进行了解释。然后用OptiSystem模拟不同泵浦功率下的EDFA增益谱,结果与实验室增益斜率数据相一致。
关键词 掺铒光纤放大器 增益斜率 泵浦功率 OptiSystem软件
在线阅读 下载PDF
上一页 1 2 36 下一页 到第
使用帮助 返回顶部