共查询到20条相似文献,搜索用时 22 毫秒
1.
利用全矢量平面波展开法(FVPWM)对采用改进的两次堆积法制备的空芯光子带隙光纤进行了数值模拟.在特定传播常数β下,光纤在500—1000 nm的波段内出现多条宽窄不同的有效光子带隙.依据有效折射率的不同,部分带隙中的空气-导模将以不同的形式存在.经过实验测试,发现测得的带隙位置相对于模拟结果向短波段发生了较明显的移动,主要原因被认为是光纤结构的纵向不均匀性和包层节点处间隙孔的存在.
关键词:
空芯光子带隙光纤
全矢量平面波展开法
有效光子带隙
空气-导模 相似文献
2.
Theoretical investigation of band-gap and mode characteristics of anti-resonance guiding photonic crystal fibres 下载免费PDF全文
With the full-vector plane-wave method (FVPWM) and the full-vector beam propagation method (FVBPM),the dependences of the band-gap and mode characteristics on material index and cladding structure parameter in antiresonance guiding photonic crystal fibres (ARGPCFs) are sufficiently analysed.An ARGPCF operating in the nearinfrared wavelength is shown.The influences of the high index cylinders,glass interstitial apexes and silica structure on the characteristics of band-gaps and modes are deeply investigated.The equivalent planar waveguide theory is used for analysing such an ARGPCF filled by the isotropic materials,and the resonance and the anti-resonance characteristics can be well predicted. 相似文献
3.
4.
Effect of interstitial air holes on Bragg gratings in photonic crystal fibre with a Ge-doped core 下载免费PDF全文
The effect of interstitial air holes on Bragg gratings in photonic
crystal fibre (PCF) with a Ge-doped core is numerically investigated
by using the beam propagation method (BPM). It is shown that the
interstitial air holes (IAHs) can make Bragg resonance wavelength
λB shift a little towards short wavelengths and
increase λB-λ1 (the wavelength spacing
between the main peak with Bragg resonance wavelength λB and the first side peak with wavelength λ1 and the
coupling coefficient к of Bragg resonance. Moreover, when
the ratio of air hole diameter (d) to pitch (Λ),
d/Λ, is small, IAHs can suppress the cladding mode
resonance. When d/Λ is large, IAHs increase the number
of mode that could strongly interact with the fundamental mode. By
comparing the transmission spectral characteristics of PCF-based
fibre Bragg grating (FBG) with IAHs with those without IAHs at the
same air-filling fraction, it is clarified that the change of
transmission spectral characteristics of PCF-based FBG with IAHs is
not due to a simple change in air-filling fraction. It is also
closely related to the distribution of interstitial air holes. 相似文献
5.
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
6.
Two kinds of fabricated hollow-core photonic crystal fibres (HC-PCFs) arc studied using finite element method (FEM) because the structures of the fibres are special, Normalized transmission spectra and transverse intensity distribution of the modes are calculated and measured. And the dispersion characteristics of these two kinds of HC- PCFs were analysed from 400 nm to 800 nm. Simulated and measured results show that the special structure could affect the properties of HC-PCFs, By comparing the simulated values with the measured results, it can be clarified that FEM is feasible and accurate for analysing photonic crystal fibres whose structures are irregular and complex. 相似文献
7.
J.-H. Yuan C.-X. Yu X.-Z. Sang G.-Y. Zhou S.-G. Li L.-T. Hou 《Applied physics. B, Lasers and optics》2009,96(2-3):337-343
Guided-mode characteristics of a hollow-core photonic band-gap fiber (HC-PBGF) fabricated by the improved twice stack-and-draw technique are investigated from near-infrared to visible wavelengths. The Full-Vector Plane-Wave Method (FVPWM) is employed to analyze the transverse field distributions in near-infrared wavelengths. The propagation mode fields in visible wavelengths are experimentally observed. The influences of glass interstitial apexes and interstitial holes on photonic band gaps and mode characteristics are analyzed. The possible degenerate state and loss mechanism of guided modes in photonic band gaps are elementarily discussed. 相似文献
8.
利用全矢量有限元法计算和分析了基于正方形格子的空芯光子带隙光纤的模式特性和泄漏损耗.通过分析发现,圆正方形空气孔按正方形格子排列的空芯光子带隙光纤可以实现宽带和有效的单模运转.随后对正方形格子空芯光子带隙光纤的泄漏损耗进行了全面分析,通过分析发现纤芯直径和包层空气孔间距的变化对泄漏损耗的影响较小,但可以通过调节包层空气孔间距来实现给定的波长具有最小的泄露损耗;圆化直径对泄漏损耗的影响较前两个因素要大,且存在一个最佳的圆化直径即dc/d=0.4;包层空气孔的
关键词:
空芯光子带隙光纤
全矢量有限元法
正方形格子
泄露损耗 相似文献
9.
应用全矢量有限元方法,研究大间距Kagome结构空芯光子晶体光纤中纤芯的大小、形状与壁厚对光纤传输损耗谱的影响。结果表明,某些纤芯尺寸会造成包层中的结构缺陷,易使纤芯基模、表面模及包层模之间发生能量耦合,产生较大损耗。而纤芯形状与壁厚的改变会引起表面模式的变化,从而影响发生在基模与表面模之间反向耦合的位置和强度,使光纤传输频带变窄和损耗变大。据此,提出Kagome结构光纤的纤芯设计思路,即纤芯的大小应使包层保持完整的微结构,纤芯形状应与包层中的单元微结构相楔合,纤芯壁厚应与包层中玻璃支柱的宽度相同。 相似文献
10.
A simple model for approximate bandgap structure calculation of all-solid photonic bandgap fibre based on an array of rings 下载免费PDF全文
A simple model for approximate bandgap structure calculation of all-solid photonic bandgap fibre based on an array of rings is proposed. In this model calculated are only the potential modes of a unit cell, which is a high-index ring in the low-index background for this fibre, rather than the whole cladding periodic structure based on Bloch's theorem to find the bandgap. Its accuracy is proved by comparing its results with the results obtained by using the accurate full-vector plane-wave method. High speed in computation is its great advantage over the other exact methods, because it only needs to find the roots of one-dimensional analytical expressions. And the results of this model, mode plots, offer an ideal environment to explore the basic properties of photonie bandgap clearly. 相似文献
11.
A simple model for approximate bandgap structure calculation of all-solid photonic bandgap fibre based on an array of rings 下载免费PDF全文
A simple model for approximate bandgap structure calculation of
all-solid photonic bandgap fibre based on an array of rings is
proposed. In this model calculated are only the potential modes of a
unit cell, which is a high-index ring in the low-index background for
this fibre, rather than the whole cladding periodic structure based
on Bloch's theorem to find the bandgap. Its accuracy is proved by
comparing its results with the results obtained by using the accurate
full-vector plane-wave method. High speed in computation is its great
advantage over the other exact methods, because it only needs to find
the roots of one-dimensional analytical expressions. And the results
of this model, mode plots, offer an ideal environment to explore the
basic properties of photonic bandgap clearly. 相似文献
12.
13.
Highly efficient Cherenkov radiation generation in the irregular point of hollow-core photonic crystal fiber 下载免费PDF全文
Highly efficient Cherenkov radiation(CR) is generated by the soliton self-frequency shift(SSFS) in the irregular point of a hollow-core photonic crystal fiber(HC-PCF) in our laboratory.The impacts of pump power and wavelength on the CR are investigated,and the corresponding nonlinear processes are discussed.When the average power of the 120 fs pump pulse increases from 500 mW to 700 mW,the Raman soliton shifts from 2210 nm to 2360 nm,the output power of the CR increases by 2.3 times,the maximum output power ratio of the CR at 539 nm to that of the residual pump is calculated to be 24.32:1,the width of the output optical spectrum at the visible wavelength broadens from 35 nm to 62 nm,and the conversion efficiency η of the CR in the experiment can be above 32%. 相似文献
14.
Photonic band structures of two-dimensional photonic crystals with deformed lattices 总被引:2,自引:0,他引:2 下载免费PDF全文
Using the plane-wave expansion method, we have calculated and analysed the
changes of photonic band structures arising from two kinds of deformed
lattices, including the stretching and shrinking of lattices. The square
lattice with square air holes and the triangular lattice with circular air
holes are both studied. Calculated results show that the change of lattice
size in some special ranges can enlarge the band gap, which depends strongly
on the filling factor of air holes in photonic crystals; and besides, the
asymmetric band edges will appear with the broken symmetry of lattices. 相似文献
15.
基于传输矩阵法,数值研究了掺杂对一维光子晶体带隙特征的影响。研究表明:掺杂时,禁带中心会出现一导带,导带深度会随着掺杂位置、杂质折射率的变化而发生变化。当晶体结构给定时,总存在一个掺杂位置,使其禁带中心的导带深度达到最深;而对于给定的掺杂位置,当杂质折射率为某特定值时,禁带中心同样也会出现一个深度最深的导带,这种特性可应用于滤波器件和光学谐振腔的设计。 相似文献
16.
Yang Yue Guiyun Kai Zhi Wang Yan Li Chunshu Zhang Yunfei Lu Tingting Sun Long Jin Jianguo Liu Yange Liu Shuzhong Yuan Xiaoyi Dong 《Optics Communications》2006,268(1):46-50
In this paper, we propose a novel photonic crystal fibre (PCF) with high phase birefringence and very low group birefringence. It is composed of a solid silica core and a cladding with helix-pattern air holes. Using a full-vector finite-element method, we study the phase and group modal birefringence of such PCF at various air-hole sizes, pitches and wavelengths. Owing to this innovative structure of air holes, a high phase to group modal birefringence rate is obtained. Its phase modal birefringence is as large as 10−4 magnitude; however, the group modal birefringence of this PCF is at 10−7-10−6. The phase birefringence is 2 orders of magnitude larger than group birefringence over a broad wavelength span, which means that the light with different polarization and effective index has almost a same group velocity. As a result, the group modal birefringence that closely relates to the polarization modal dispersion is negligible. 相似文献
17.
Broad and ultra-flattened supercontinuum generation in the visible wavelengths based on the fundamental mode of photonic crystal fibre with central holes 下载免费PDF全文
By coupling a train of femtosecond pulses with 100 fs pulse width at a repetition rate of 76 MHz generated by a mode-locked Ti:sapphire laser into the fundamental mode of photonic crystal fibre(PCF) with central holes fabricated through extracting air from the central hole,the broad and ultra-flattened supercontinuum(SC) in the visible wavelengths is generated.When the fundamental mode experiences an anomalous dispersion regime,three phases in the SC generation process are primarily presented.The SC generation(SCG) in the wavelength range from 470 nm to 805 nm does not emerge significant ripples due to a higher pump peak power and the corresponding mode fields at different wavelengths are observed using Bragg gratings.The relative intensity fluctuations of output spectrum in the wavelength ranges of 530 nm to 640 nm and 543 nm to 590 nm are only 0.028 and 0.0071,respectively. 相似文献
18.
传统光纤包层中仅存在泄漏的倏逝波,能量较小,不利于包层传感的应用。增大包层中的能量,实现整体包层导光是提高光纤传感灵敏度的有效途径。从理论上分析了利用空芯带隙型光子晶体光纤(HC-PCF)包层进行导光的机理。在实验上选用带隙外的冷光源和激光对一种典型结构的HC-PCF进行了空气孔包层的导光实验,并利用折射率引导型光子晶体光纤和单模光纤进行对比实验。结果表明,带隙范围外光波在HC-PCF中传输时将不受禁带效应的约束泄露至包层中重新分布。包层中SiO2与空气孔的周期型结构将光波约束在高折射率介质中,实现HC-PCF整体空气孔包层中光波的稳定传输。PBG-PCF包层的整体导光在传感上有提高灵敏度的潜在价值。 相似文献
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20.
Bekker E. V. Benson T. M. Sewell P. Melnikov L. A. 《Optical and Quantum Electronics》2004,36(8):733-744
The plane wave and localized function expansion methods are established for bandgap and modal calculations of holey fibres. The calculations rely on evaluating the Fourier transform coefficients of the dielectric constant profile. In this paper we derive a generalized formula for determining these coefficients for holey fibres with holes of arbitrary polygonal shape. The accuracy of the Fourier representation is studied for different hole shapes rotated at various angles to the lattice. We combine the approach with the localized function method to study the modal properties of some holey fibres, reporting new numerical results on the influence of the hole shape on the modal and group velocity dispersion of microstructured fibres with rhombic holes aligned along radial lines. 相似文献