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1.
Broadband tunable optical amplification based on modulation instability characteristic of high-birefringence photonic crystal fibers 下载免费PDF全文
A novel high-birefringence photonic crystal fiber (HB-PCF) with two zero-dispersion wavelengths (ZDWs) is designed, and an extraordinarily high modal birefringence of 1.56×10-2 is obtained at pump wavelength λp=1850nm. With the designed HB-PCF, the effect of the pump parameters on the modulation instability (MI) in the anomalous dispersion region close to the second ZDWs of the HB-PCF is comprehensively studied in this work. A broadband and tunable optical amplification is achieved by controlling the pump power and the pump wavelength based on the combined operation of Raman effect and cross phase modulation. By optimizing the pump parameters, the amplification bandwidth along the fiber slow axis reaches 152 nm for the pump power Pp=280W and the pump wavelength λp=1675nm, while the gain bandwidth along the fiber fast axis is 165 nm for the pump power Pp=600W and the pump wavelength λp=1818nm. 相似文献
2.
This paper theoretically studies the double-pumped fibre-optical
parametric amplifiers (FOPAs) in photonic crystal fibres. Two
distinct working regimes of FOPAs are researched, which depend on the
dispersion at the central wavelength of the two pumps. Extremely
broad tuning range can be obtained when the central pump wavelength
is in the normal dispersion regime and is insensitive to the
wavelength separation between the two pumps, while the tuning range
is narrow in the anomalous dispersion regime and can be significantly
enhanced by increasing the wavelength separation. Impacts of
higher-order dispersions and temporal walk-off on the gain spectra
are also discussed. 相似文献
3.
This paper theoretically studies the double-pumped fibre-optical parametric amplifiers (FOPAs) in photonic crystal fibres. Two distinct working regimes of FOPAs are researched, which depend on the dispersion at the central wavelength of the two pumps. Extremely broad tuning range can be obtained when the central pump wavelength is in the normal dispersion regime and is insensitive to the wavelength separation between the two pumps, while the tuning range is narrow in the anomalous dispersion regime and can be significantly enhanced by increasing the wavelength separation. Impacts of higher-order dispersions and temporal walk-off on the gain spectra are also discussed. 相似文献
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Modulation instability of femtosecond pulses in fibres with slowly decreasing dispersion 总被引:2,自引:0,他引:2 下载免费PDF全文
In this paper,we investigate the modulation instability for generating femtosecond pulses in fibres with slowly decreasing dispersion.Higher-order dispersion and higher-order nonlinear effects are taken into account when the continuous wave or quasi-continuous wave evolves into sub-picosecond and femtosecond pulses by modulation instability in the optical fibres.Our research results show that the gain spectrum of the dispersion-decreasing fibres is much wider than that in conventional fibres.The third-order dispersion effect has no contribution to gain spectrum,while the self-steepening effect reduces the maximum value and gain bandwidth,and the Raman self-scattering effect widens the extent to which the modulation instability occurs. 相似文献
6.
根据参量放大和拉曼效应共同作用下的耦合波方程,在考虑高阶色散情况下,当输入泵浦波偏振方向同双折射轴成45时,通过引入拉曼增益的洛伦兹模型,研究了高双折射光纤中,参量放大和拉曼效应共同作用下的增益谱随相关参量的变化关系。结果表明:高双折射光纤中,在不同色散区,不同的输入参量(输入功率、群速度失配等)条件下,参量放大和拉曼效应共同作用下的增益谱受到高阶色散的影响,增益谱的结构、强度和谱宽产生了变化, 高阶色散对增益谱的影响不可忽略;可以利用增益谱在大群速度失配区域远离中心频率偏移的性质,提取T频率脉冲。 相似文献
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Cross-phase modulation instability in optical fibres with exponential saturable nonlinearity and high-order dispersion 下载免费PDF全文
Utilizing the linear-stability analysis, this paper
analytically investigates and calculates the condition and gain
spectra of cross-phase modulation instability in optical fibres in
the case of exponential saturable nonlinearity and high-order
dispersion. The results show that, the modulation instability
characteristics here are similar to those of conventional saturable
nonlinearity and Kerr nonlinearity. That is to say, when the
fourth-order dispersion has the same sign as that of the
second-order one, a new gain spectral region called the second one
which is far away from the zero point may appear. The existence of
the exponential saturable nonlinearity will make the spectral width
as well as the peak gain of every spectral region increase with the
input powers before decrease. Namely, for every spectral regime,
this may lead to a unique value of peak gain and spectral width for
two different input powers. In comparison with the case of
conventional saturable nonlinearity, however, when the other
parameters are the same, the variations of the spectral width and
the peak gain with the input powers will be faster in case of
exponential saturable nonlinearity. 相似文献
9.
Zero dispersion wavelength and dispersion slope control of hollow-core photonic bandgap fibres 下载免费PDF全文
This paper investigates the zero dispersion wavelength and
dispersion slope control of hollow-core photonic bandgap fibres
(PBGFs) by using a full-vector finite element method. By simulation
we found that theoretically the zero dispersion wavelength can be
tailored by respectively changing the rounded diameter of air holes,
pitch, refractive index, normalized thickness of core rings, and
hole diameter to pitch ratio. At the same time the tailoring of
dispersion slope can also be realized by changing the rounded diameter
of air holes or pitch or normalized thickness of core rings. To
illustrate the reasonability of fibre designs, this paper also gives
the variance of normalized interface field intensity which measures
the scattering loss relatively versus wavelength for different
designs. From the viewpoint of loss, varying the rounded diameter
and the thickness of core ring could shift zero wavelength but it is
difficult to get the required parameters within so tiny range in
practical drawing of PBGFs, on the other hand, it is possible in
practice to respectively alter the pitch and refractive index to
shift zero wavelength. But varying hole diameter to pitch ratio is
not worthwhile because they each induce large increase of loss and
narrowness of transmission bandwidth. The zero dispersion wavelength
can be engineered by respectively varying the rounded diameter of air
holes, pitch, refractive index, and normalized thickness of core
rings without incurring large loss penalties. 相似文献
10.
Improved high birefringence photonic crystal fibres with dispersion flattened and single mode operation 下载免费PDF全文
A kind of improved high birefringence photonic crystal fibre (PCF) is proposed in this paper. The characteristics of birefringence, dispersion and leakage loss are studied by the multipole method. Numerical results show that the improved PCF possesses the properties of a flat dispersion and single mode operation. Moreover, with the operating wavelength λ = 1.55μm, the modal birefringence increases greatly in comparison with that of the original PCF, and the leakage loss is about 104 times smaller than that of the original PCF because the modification gives rise to the strong confinement of guided modes. It is expected that the improved PCF can be used as high birefringence and dispersion flattened fibres. 相似文献
11.
提出了一种兼具低损耗、宽带近零色散和高非线性的光子晶体光纤结构,该结构光纤包层空气孔直径从纤芯向外层方向渐进增加;应用多极法,通过改变包层空气孔间距Λ、各层空气孔直径和空气孔层数Nr,对光子晶体光纤色散、损耗和非线性特性进行分析,获得了各特性随包层结构参数变化的规律,并最终设计出最佳结构参数。计算结果表明,该结构光纤存在3个零色散点,在1.25~1.55 μm较宽的波长范围内,色散值波动小于0.27 ps·nm−1·km−1,色散斜率小于0.008 ps·km−1·nm−2,1.55 μm波长处损耗为0.021 dB/km,在常用的飞秒激光泵浦波长0.8,1.06,1.55 μm处非线性系数分别达到78.6,60.4,38.2 W−1·km−1。 相似文献
12.
Ultra-broadband modulation instability gain characteristics in As_2S_3 and As_2Se_3 chalcogenide glass photonic crystal fiber 下载免费PDF全文
Based on the designed As_2Se_3 and As_2S_3 chalcogenide glass photonic crystal fiber(PCF) and the scalar nonlinear Schrdinger equation,the effects of pump power and wavelength on modulation instability(MI) gain are comprehensively studied in the abnormal dispersion regime of chalcogenide glass PCF.Owing to high Raman effect and high nonlinearity,ultra-broadband MI gain is obtained in chalcogenide glass PCF.By choosing the appropriate pump parameter,the MI gain bandwidth reaches 2738 nm for the As_2Se_3 glass PCF in the abnormal-dispersion region,while it is 1961 nm for the As_2S_3 glass PCF. 相似文献
13.
Stochastic numerical simulations are used to study the statistical properties of supercontinuum spectra generated in photonic
crystal fibre with two zero dispersion wavelengths. For picosecond pulse excitation, we examine how the statistical properties
of solitons generated on the long wavelength edge of the supercontinuum (``optical rogue waves") are modified by energy transfer
to dispersive waves across the second zero dispersion wavelength. The soliton statistics (characterized in terms of peak power,
wavelength and pulse duration) are shown to be strongly modified by the mechanism of dispersive wave generation, with the
detailed form of the probability distribution depending strongly on input pulse energy. 相似文献
14.
Hui ZQ 《光谱学与光谱分析》2011,31(10):2611-2617
研究了信号与泵浦光同向传输,在色散平坦高非线性光子晶体光纤中的多泵浦四波混频光谱增益特性,从光谱学的角度分析了泵浦光波长漂移,泵浦光偏振方向平行与正交,信号光相对于泵浦光偏振态失配,二者总功率对多泵浦四波混频光谱增益特性的影响,探讨了泵浦光数目对多泵浦四波混频光谱增益特性的冲击。研究发现在36.4 nm波长范围,二者偏振态匹配时多泵浦四波混频效果最好,同时,多泵浦四波混频效应对偏振极为敏感,若两束泵浦光偏振态垂直,则它们分别与信号光发生四波混频,反之,则两束泵浦光之间亦会发生四波混频作用,且在正交泵浦的前提下,信号光偏振方向变化会直接导致各闲频光增益大小发生变化;进一步指出当采用三束连续泵浦光时,同样可以在一定波长范围内实现多泵浦四波混频效应。这些研究对于开发基于光子晶体光纤中多泵浦四波混频效应工作的超快光子器件具有一定的指导意义。 相似文献
15.
High birefringence, low loss terahertz photonic crystal fibres with zero dispersion at 0.3 THz 下载免费PDF全文
A terahertz photonic crystal fibre (THz-PCF) is designed for terahertz wave propagation. The dispersion property and model birefringence are studied by employing the finite element method. The simulation result reveals the changing patten of dispersion parameter versus the geometry. The influence of the large frequency band of terahertz on birefringence is also discussed. The design of low loss, high birefringence THz-PCFs with zero dispersion frequency at 0.3 THz is presented. 相似文献
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An effective feedback algorithm is proposed to dynamically control the gain spectra of multi-wavelength pumped broadband Raman amplifiers. Based on Raman coupling power equations, a simple saturation factor is introduced to achieve the adjusting matrix. By using this method, efficient pump adjustment can be carried out to accomplish wide-range dynamic gain spectrum control (larger than 22 dB dynamic range) as well as automatic gain clamping even for 90 nm bandwidth, highly-saturated RAs. Moreover, this algorithm can be well applied to different fiber types as well as pumping schemes. Some useful guidelines are also demonstrated. 相似文献
18.
利用多极法对光子晶体光纤的色散特性进行了模拟, 通过设计合适的结构参数, 得到了具有3个零色散波长的单模光纤.对中心纤芯有1个微小空气孔光子晶体光纤的色散特性进行了分析, 设计出了具有4个零色散波长的色散曲线.分析了零色散波长随光纤结构的变化规律, 这些零色散波长的位置和间距可以在很大波长范围内灵活调节. 具有多个零色散波长的光纤可以得到色散值极低的超平坦色散曲线. 多个零色散波长光纤能产生丰富的相位匹配曲线, 可以有效地控制光孤子及超短脉冲的四波混频及共振散射产生的光谱特性. 相似文献
19.
Temperature dependence of birefringence in olarization-maintaining photonic crystal fibres 下载免费PDF全文
In this paper,the temperature dependence of birefringence in polarization maintaining photonic crystal fibres(PMPCFs) is investigated theoretically and experimentally.Utilizing the structural parameters of the PM-PCF samples in the experiment,two effects leading to the birefringence variation under different temperatures are analysed,which are the thermal expansion of silica material and the refractive index variation due to the temperature variation.The actual birefringence variation of the PM-PCF is the combination of the two effects,which is in the order of 10-9 K-1 for both fibre samples.Calculation results also show that the influence of refractive index variation is the dominant contribution,which determines the tendency of the fibre birefringence variation with varying temperature.Then,the birefringence beat lengths of the two fibre samples are measured under the temperature,which varies from -40℃ to 80℃.A traditional PANDA-type polarization maintaining fibre(PMF) is also measured in the same way for comparison.The experimental results indicate that the birefringence variation of the PM-PCF due to temperature variation is far smaller than that of the traditional PMF,which agrees with the theoretical analysis.The ultra-low temperature dependence of the birefringence in the PM-PCF has great potential applications in temperature-insensitive fibre interferometers,fibre sensors,and fibre gyroscopes. 相似文献
20.
设计了一种铅硅酸盐SF57 材料的光子晶体光纤, 利用有限元法数值模拟了该光纤的 色散特性. 研究结果显示在整个透明波段光纤具有正常色散. 利用自适应分布傅里叶法求解非线性薛定谔方程, 对中心波长为1550 nm, 初始脉宽为150 fs 的脉冲在该光纤中传输进行了模拟, 获得了关于入射脉冲中心波长对称的展宽范围超过了600 nm 的超平坦连续光谱, 并且光谱具有极其稳定和 相干的特性.
关键词:
光子晶体光纤
超连续谱产生
正常色散 相似文献