共查询到20条相似文献,搜索用时 31 毫秒
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Astratov V.N. Culshaw J.S. Stevenson R.M. Whittaker D.M. Skolnick M.S. Krauss T.F. de la Rue R.M. 《Lightwave Technology, Journal of》1999,17(11):2050-2057
Sharp resonance features are observed in the polarized reflectivity spectra of semiconductor photonic crystals fabricated by deep periodic patterning of AlGaAs surface waveguides. Both one- (1-D) and two-dimensional (2-D) lattices are studied by angular dependent reflectivity. By comparison with theory we show that the sharp features in reflectivity arise from resonant coupling of the external radiation to the folded band structure of the photonic crystal waveguides. Wavevector selective coupling to “heavy photon” states at the edge of the photonic Brillouin zone is demonstrated for the 1-D lattices. In the case of the 2-D lattices we observe polarization mixing of the photonic hands. Theoretical reflectivity spectra were obtained from a numerical solution of Maxwells equations for the patterned waveguide and were found to be in very good agreement with experiment 相似文献
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Notomi M. Shinya A. Yamada K. Takahashi J.-I. Takahashi C. Yokohama I. 《Quantum Electronics, IEEE Journal of》2002,38(7):736-742
We experimentally demonstrate the structural tuning of the waveguiding modes of line defects in photonic crystal (PC) slabs. By tuning the defect widths, we realized efficient single-mode waveguides that operate within photonic band gap frequencies in silicon-on-insulator PC slabs. The observed waveguiding characteristics agree very well with three-dimensional finite difference time-domain calculations. We also directly measured the propagation loss of the line defect waveguides and obtained a value of 6 dB/mm 相似文献
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We have designed and fabricated waveguides that incorporate two-dimensional (2-D) photonic crystal geometry for lateral confinement of light, and total internal reflection for vertical confinement. Both square and triangular photonic crystal lattices were analyzed. A three-dimensional (3-D) finite-difference time-domain (FDTD) analysis was used to find design parameters of the photonic crystal and to calculate dispersion relations for the guided modes in the waveguide structure. We have developed a new fabrication technique to define these waveguides into silicon-on-insulator material. The waveguides are suspended in air in order to improve confinement in the vertical direction and symmetry properties of the structure. High-resolution fabrication allowed us to include different types of bends and optical cavities within the waveguides. 相似文献
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Sugimoto Y. Ikeda N. Carlsson N. Asakawa K. Kawai N. Inoue K. 《Quantum Electronics, IEEE Journal of》2002,38(7):760-769
An AlGaAs-based near-infrared 2-D photonic crystal (PC) with an air-bridge structure featuring defect waveguides has been developed. For the sample without defect waveguides, measurements of the optical transmission characteristics in the wavelength range from 850 nm to 1100 nm showed a deep attenuation due to a bandgap with 30-35 dB attenuation and transmittance of nearly 100% for the guided modes. Optical propagation properties of defect waveguides were obtained by two methods: measurements of transmission spectra and plan-view observations of the optical beam trace along the waveguide with an infrared-vidicon camera. 3-D finite-difference time-domain simulations for the band structure and transmission spectra in the air-bridge slab with and without defect waveguides have revealed the appearance of four defect propagation modes specific to the defect waveguide, between two slab modes for the defect-free photonic crystal slab. These defect modes were experimentally identified in the measured transmission spectra 相似文献
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Baba T. Motegi A. Iwai T. Fukaya N. Watanabe Y. Sakai A. 《Quantum Electronics, IEEE Journal of》2002,38(7):743-752
Straight single-line defect optical waveguides in photonic crystal slabs are designed by the finite difference time-domain method and fabricated into a silicon-on-insulator (SOI) wafer. By employing an airbridge structure, clear light propagation for both polarizations is observed without any leakage along the waveguide. This experimental result is well explained by photonic bands of pure guided modes. Minimum propagation loss is estimated to be 11 dB/mm. This value is lower than that reported so far for three-line-defect waveguides with an SOI slab structure and almost comparable to that for an index confinement waveguide with a rectangular Si core. This propagation loss is dominated by the scattering loss by some irregularities. However, photonic crystal waveguides have the possibility of an essential lower scattering loss than in the index confinement waveguide because of the inhibition of radiation modes by the photonic bandgap 相似文献
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Karle T.J. Chai Y.J. Morgan C.N. White I.H. Krauss T.F. 《Lightwave Technology, Journal of》2004,22(2):514-519
We demonstrate the compression of picosecond pulses using the large group velocity dispersion available from planar photonic crystal (PhC) coupled cavity waveguides (CCWs). A maximum pulsewidth reduction of 40%, from 1.91 to 1.17 ps, is achieved, in transmission through an 8-/spl mu/m-long planar PhC waveguide. The equivalent dispersion value is >10/sup 6/ times larger than that available from standard single-mode fiber, at the pulse center wavelength of 1536 nm. The device performance is analyzed with the aid of both two-dimensional (2-D) eigenmode expansion and 2-D finite-difference time-domain (FDTD) models. The models included the material dispersion of the GaAs/AlGaAs heterostructure, into which the PhCs are etched, and show remarkable agreement with experiment. 相似文献
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Tanaka Y. Nakamura H. Sugimoto Y. Ikeda N. Asakawa K. Inoue K. 《Quantum Electronics, IEEE Journal of》2005,41(1):76-84
Two-dimensional (2-D) photonic crystal (PC) directional couplers (DCs) that have a triangular lattice pattern of air holes in a planar dielectric slab are theoretically and experimentally analyzed. Unlike the 2-D PC DC structure with a dielectric rod in air, which is frequently used in theoretical studies, more practical PC DCs tend to be multimode in nature and exhibit a large group velocity dispersion, thus creating decoupling points in the dispersion relation without any additional modifications to the structure. The multimode nature and large dispersion lead to interference which degrades the coupling properties. By inserting three rows of air holes between neighboring line-defect waveguides in order to separate them, we have successfully reduced the multimode region and obtained a single-mode region. In this case, the large dispersion allows the creation of a PC DC with wavelength selectivity and a coupling length as short as 30 a,/spl sim/10 /spl mu/m for a=345 nm, where a is the lattice constant. The transmission spectra obtained experimentally showed good agreement with the theory whereas their transmission ranges were restricted to those of bent waveguides. These results are encouraging for practical application to optical communications. 相似文献
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A concept for dispersion compensation in transmission is proposed, based on modes anti-crossing in photonic crystal (PC) line-defect waveguides. Quasi-constant positive and negative dispersion is possible in order of 100 ps/nm/mm on the bandwidth of 100 GHz. An adiabatic taper is proposed for efficient coupling into PC structure. 相似文献
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The authors report room temperature lasing by pulsed photopumping at line and point composite defects, i.e. a 60/spl deg/-bend, a Y-branch and an intersection of single line defect waveguides, in a GaInAsP photonic crystal slab. The lasing wavelength was different from the simple line defect lasing mode. This indicates that such waveguide components act as microcavities with localised modes. 相似文献
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We investigate the performance and guiding properties of waveguides fabricated in a finite two-dimensional (2-D) photonic bandgap (PBG) structure. Confinement in the direction perpendicular to the plane of periodicity is achieved by fabricating the 2-D PBG structure in a high dielectric layer enclosed by two lower dielectric layers. Simulations using the finite-difference time-domain (FDTD) method are performed to investigate the energy transport in such waveguides. Good qualitative agreement is found with the experimental observations 相似文献
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设计了一种基于二维光子晶体的太赫兹带通滤波器,通过在线缺陷的光子晶体波导两侧引入对称的点缺陷形成谐振腔,在太赫兹频段实现了较好的带通滤波特性。这种二维光子晶体带通滤波器具备较宽的通带带宽,同时还可以通过增加多组对称点缺陷的方式实现多个谐振腔的级联,进一步提高带外抑制特性,可满足太赫兹通信或雷达系统的应用需求,具有良好的应用价值。 相似文献
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Yamada K. Notomi M. Shinya A. Takahashi C. Takahashi J. Morita H. 《Electronics letters》2002,38(2):74-75
Single-mode lightwave transmission was observed in novel line-defect photonic-crystal (PC) waveguides. The waveguide structure is constructed by adding phase-shifted holes in an ordinary missing-hole line defect. This device permits a fine single-mode lightwave transmission even though the waveguide structure is fabricated on silicon-on-insulator (SOI) substrate, which seriously promotes off-plane leakage of waveguiding modes 相似文献
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Ultrashort 2-D photonic crystal directional couplers 总被引:5,自引:0,他引:5
A. Martinez F. Cuesta J. Marti 《Photonics Technology Letters, IEEE》2003,15(5):694-696
A novel approach to reduce the coupling length and to increase the coupling coefficient in waveguide directional couplers implemented on two-dimensional (2-D) photonic crystals (PhC) is proposed. To increase the coupling coefficient of a 2-D PhC directional coupler, which is composed of two parallel PhC waveguides separated by one or several rows of rods, the radius of the rods between both waveguides is reduced. The application of this feature to ultrasmall channel interleavers and wavelength demultiplexers is addressed. 相似文献
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Combrie S. De Rossi A. Morvan L. Tonda S. Cassette S. Dolfi D. Talneau A. 《Electronics letters》2006,42(2):86-88
The group delay in low-loss, singlemode, 1 mm-long photonic crystal slab waveguides is measured using the phase shift technique for the first time. Low group velocities (相似文献
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Painter O.J. Husain A. Scherer A. O'Brien J.D. Kim I. Dapkus P.D. 《Lightwave Technology, Journal of》1999,17(11):2082-2088
Room temperature lasing from optically pumped single defects in a two-dimensional (2-D) photonic bandgap (PBG) crystal is demonstrated. The high-Q optical microcavities are formed by etching a triangular array of air holes into a half-wavelength thick multiquantum-well waveguide. Defects in the 2-D photonic crystal are used to support highly localized optical modes with volumes ranging from 2 to 3 (λ/2n)3. Lithographic tuning of the air hole radius and the lattice spacing are used to match the cavity wavelength to the quantum-well gain peak, as well as to increase the cavity Q. The defect lasers were pumped with 10-30 ns pulses of 0.4-1% duty cycle. The threshold pump power was 1.5 mW (≈500 μW absorbed) 相似文献
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Coupling between photonic crystal waveguides 总被引:3,自引:0,他引:3
Kuchinsky S. Golyatin V.Y. Kutikov A.Y. Pearsall T.R. Nedelikovic D. 《Quantum Electronics, IEEE Journal of》2002,38(10):1349-1352
A calculation procedure for evaluation of the coupling length of two parallel coupled channel waveguides in a planar photonic crystal is proposed. The first step of the calculation is evaluation of the band structure of a photonic crystal containing two coupled linear defects. The eigenvalue corresponding to eigenstates localized in the linear defect (the waveguide) is split due to the coupling. This splitting is treated within the coupled-mode theory that yields a simple relation between the splitting and the coupling length. The MIT photonic bands code is used to evaluate the coupling between channel waveguides in silicon./sup 1/ These calculations show that in contrast to the finite-difference time-domain approach, the method is effective for three-dimensional light propagation. 相似文献