共查询到20条相似文献,搜索用时 15 毫秒
1.
J. S. Yeo R. N. Bicknell S. Mathai P. E. Kornilovitch H.-P. Kuo P. Rosenberg M. Tan L. King 《Applied Physics A: Materials Science & Processing》2009,95(4):1073-1077
Hollow metal waveguides feature well collimated beams and small losses across air gaps. This enables introduction of multiple
optical beam splitters, or taps, along the waveguide to multicast signals from a source to multiple receivers. The splitters
need to be of sufficient thickness to provide mechanical integrity and ease of handling. As a result, passing through the
thickness leads to a beam walk-off. Walk-off dependence on the splitter thickness and its effect on the system optical efficiency are investigated. Two methods
to compensate the walk-off are described: by offsetting the outgoing waveguide, and by introducing an additional symmetric
optical element to shift the beam back to the original optical path. Both methods have been shown to effectively mitigate
the walk-off effects. 相似文献
2.
Michael Tan Paul Rosenberg Jong Souk Yeo Moray McLaren Sagi Mathai Terry Morris Huei Pei Kuo Joseph Straznicky Norman P. Jouppi Shih-Yuan Wang 《Applied Physics A: Materials Science & Processing》2009,95(4):945-953
Buses have historically provided a flexible communications structure in computer systems. However, signal integrity constraints
of high-speed electronics have made multi-drop electrical buses infeasible. Instead, we propose an optical data bus for computer
interconnections. It has two sets of optical waveguides, one as a fan-out and the other as a fan-in, that are used to interconnect
different modules attached to the bus. A master module transmits optical signals which are received by all the slave modules
attached to the bus. Each slave module in turn sends data back on the bus to the master module. Arrays of lasers, photodetectors,
waveguides, microlenses, beamsplitters, and Tx/Rx integrated circuits are used to realize the optical data bus. With 1 mW
of laser power, we are able to interconnect eight different modules at 10 Gb/s per channel. An aggregate bandwidth of over
25 GB/s is achievable with 10-bit wide signaling paths. 相似文献
3.
Robert Bicknell Laura King Charles E. Otis Jong-Souk Yeo Neal Meyer Pavel Kornilovitch Scott Lerner Lenward Seals 《Applied Physics A: Materials Science & Processing》2009,95(4):1059-1066
As data rates continue to increase in high-performance computer systems and networks, it is becoming more difficult for copper-based
interconnects to keep pace. An alternative approach to meet these requirements is to move to optical-based interconnect technologies
which offer a number of advantages over the legacy copper-based solutions. In order to meet the stringent requirements of
high performance and low cost, manufacturable waveguide technologies must be developed. Past solutions have often employed
polymer waveguide technologies, which can be expensive and limited by modal dispersion. In the present work, hollow metal
waveguides (HMWGs) are investigated as a potential alternative. These waveguides demonstrate very low optical losses of <0.05 dB/cm
and the capability to transmit at extremely high data rates. The fabrication, modeling, characterization of the HMWGs are
discussed to enable photonic interconnect solutions for future generations of computer and server products. 相似文献
4.
Design and evaluation of an arbitration-free passive optical crossbar for on-chip interconnection networks 总被引:1,自引:0,他引:1
Linjie Zhou Stevan S. Djordjevic Roberto Proietti Dan Ding S. J. B. Yoo Rajeevan Amirtharajah Venkatesh Akella 《Applied Physics A: Materials Science & Processing》2009,95(4):1111-1118
With recent advances in silicon nanophotonics, optical crossbars based on CMOS-compatible microring resonators have emerged
as viable on-chip optical interconnection networks to deliver high-bandwidth communication at low power dissipation with a
small footprint. This paper describes the design, fabrication and evaluation of an arbitration-free passive crossbar based
on a microring resonator matrix that can be used to route wavelength division multiplexing (WDM) signals across the chip.
The salient feature of the proposed design is the ability to support multicasting and many-to-one communication efficiently
(without arbitration), which makes it suitable for implementing cache coherency protocols and on-chip interconnect in future
many-core processors. 相似文献
5.
Spectrally selective splitters with metal-dielectric-metal (MDM) subwavelength waveguides are proposed in this paper. The
method is based on the Bragg grating structure with periodically modulated MDM waveguide width, which delivers a stop band
effect for the surface plasmon propagating in the waveguide. By adding appropriate Bragg grating structure in one or more
arms of the waveguide splitters, light in a certain frequency range can be readily guided into the desired directions, as
demonstrated numerically by the finite-difference time-domain method. Dependence and optimization of the geometrical parameters
are also considered in this paper. 相似文献
6.
We design a multi-layer cladding large-core planar waveguide that supports a single guided mode. The waveguide works on the
principle of higher-order mode discrimination. The cladding of the waveguide is formed by alternate low- and high- index regions,
which helps leaking out of higher-order modes while retaining the fundamental mode over the entire length of the waveguide.
The structure is analyzed by the transfer-matrix method and the leakage losses of the modes have been calculated. We show
that a waveguide formed in silica with numerical aperture 0.24 and core width 10 μm can be designed to exhibit single-mode
operation at 1550-nm wavelength. Such a structure should find applications in high-power planar waveguide lasers and amplifiers. 相似文献
7.
J. Beals N. Bamiedakis A. Wonfor R. V. Penty I. H. White J. V. DeGroot K. Hueston T. V. Clapp M. Glick 《Applied Physics A: Materials Science & Processing》2009,95(4):983-988
An optical backplane based on a meshed polymer waveguide architecture enabling high-speed board-to-board optical interconnection
is presented. This planar array of multimode polymer waveguides can provide passive strictly non-blocking links between server
line cards fitted with optical transmitter and receiver arrays. This architecture offers a scalable and low-cost solution
to the bandwidth limitations faced by electrical backplanes and is suitable for PCB integration. The reported backplane demonstrator
uses a matrix of 100 waveguides each capable of 10 Gb/s operation to interconnect 10 cards for a total capacity of a terabit
per second aggregate data rate in multicast mode. Characterisation of the backplane demonstrator reveals low link losses of
2 to 8 dB for a multimode fibre input and crosstalk values below −35 dB. Error free data transmission at 10 Gb/s is achieved
with a power penalty of only 0.2 dB at a bit-error-rate of 10−9. Additionally, lossless operation of a Gigabit Ethernet link over the backplane is achieved even when using the worst-case
highest loss links. 相似文献
8.
9.
H. Kurt 《Applied physics. B, Lasers and optics》2009,95(2):341-344
To obtain highly directional light output from photonic crystal waveguides (PCWs), the emission characteristics of the narrow-width
waveguide structures are investigated by tailoring the geometry of the exit sides. The local structural deformations in the
form of air hole removal from the triangular-lattice photonic crystal (PC) show the effectiveness of the previously proposed
approach that was implemented by us for another type of PC. The spatial broadening of the beam is greatly suppressed. With
the modified waveguide exits, highly directional emissions with small side lobes are achieved. The frequency dependency of
the directional emissions is evaluated. We show that the divergence angles of the beams depend linearly on the wavelength
for a regular type of PCW but the modified PCW exits have local minima with respect to wavelength in terms of the divergence
angle. The present work may prove to be helpful in the design of couplers and edge-emitting lasers and in the implementation
of free-space optical communications. 相似文献
10.
M. Gorram V. Coda P. Thévenin G. Montemezzani 《Applied physics. B, Lasers and optics》2009,95(3):565-572
Photoinduced channel waveguides are created in the bulk of biased electro-optic Sr0.61Ba0.39Nb2O6 crystals by a proper combination of crossed lateral illumination waves. The measured nearly-circular steady-state guided
wave profiles agree well with theoretically expected mode profiles. The buried waveguides obtained by this technique can be
easily tailored and are dynamically reconfigurable. The dynamics of formation is found to be anisotropic, with a faster effect
for the confinement of the guided wave in the direction parallel to the applied electric field. 相似文献
11.
12.
Xu Fei Ying Wan Haiming Zhang Zhanchen Cui Daming Zhang 《Applied Physics A: Materials Science & Processing》2009,96(2):467-472
A linear fluorinated bis-phenol-A novolac resin (LFAR) for optical waveguide was synthesized based on 4,4′-(hexafluoro-isopropylidene)diphenol,
epoxy chloropropane and formaldehyde. Negative fluorinated photoresist (FP) was made by composing the LFAR, diphenyl iodonium
salt and solvent. The film, which was made by spin-coating FP, had good UV light lithograph sensitivity, large hardness and
high glass transition temperature (T
g
>170°C, after crosslinking). Low-loss optical waveguides with very smooth top surface were fabricated from the resulting FP
by direct UV exposure and chemical development. For waveguides without upper cladding, the propagation loss of the channel
waveguides was measured to be 0.21 dB/cm at 1550 nm. 相似文献
13.
A. Ródenas G. A. Torchia G. Lifante E. Cantelar J. Lamela F. Jaque L. Roso D. Jaque 《Applied physics. B, Lasers and optics》2009,95(1):85-96
The effect that femtosecond laser filamentation has on the refractive index of Nd:YAG ceramics, and which leads to the formation
of waveguide lasers, has been studied by micro-spectroscopy imaging, beam propagation experiments and calculations. From the
analysis of the Nd3+ luminescence and Raman images, two main types of laser induced modifications have been found to contribute to the refractive-index
change: (i) a lattice defect contribution localized along the self-focusing volume of the laser pulses, in which lattice damage
causes a refractive-index decrease, and (ii) a lattice strain-field contribution around and inside the filaments, in which
the pressure-driven variation of the inter-atomic distances causes refractive-index variations. Scanning near-field optical-transmission
and end-coupling experiments, in combination with beam propagation calculations, have been used to quantitatively determine
the corresponding contribution of each effect to the refractive-index field of double-filament waveguides. Results indicate
that the strain-field induced refractive-index increment is the main mechanism leading to waveguiding, whereas the damage-induced
refractive-index reduction at filaments leads to a stronger mode confinement. 相似文献
14.
P. E. Kornilovitch R. N. Bicknell J. S. Yeo 《Applied Physics A: Materials Science & Processing》2009,95(4):999-1004
Fully-connected mesh networks with local connections are described. Each connector links only nearest neighbors of the node lattice and carries enough passive pass-through
vias to provide direct one-to-one links between all the nodes. If the nodes form a one-dimensional ring, then each connector
must contain at least N(N−1)/2 physical channels. However, if the nodes are arranged in a d-dimensional hyper-torus, the number of channels per connector drops to N(N
1/d
−1)/2, which scales much more favorably at large N. Such arrangements can provide fully-meshed connectivity when parts of the network are physically inaccessible or when the
network needs to be scaled up in a modular fashion. 相似文献
15.
H. Y. Zhang Y. P. Zhang W. H. Liu Y. Q. Wang J. G. Yang 《Applied physics. B, Lasers and optics》2009,96(1):67-70
We show theoretically that the frequency range of the zero-averaged refractive-index gap can be substantially extended in
a photonic heterostructure containing negative-index materials. This photonic heterostructure consists of different one-dimensional
(1D) photonic crystals. The constituent 1D photonic crystals have to be properly chosen in such a way that their zero-averaged
refractive-index gap of the adjacent photonic crystals overlap each other. 相似文献
16.
In this paper, we propose the use of two two-dimensional photonic crystal line defect waveguides for slow light with large
delay–bandwidth product (DBP). One includes air rings localized at each side of the line defect and the other modifies the
radius and distance of holes at each side of the waveguide. We show that we can achieve a very flat band corresponding to
nearly constant group index over a broad frequency range by adjusting the parameters of the structure. We show further that
the group velocity dispersion (GVD) can reach a relatively small amount and the DBP can be more than 0.6 for the first waveguide
and 0.34 for the second waveguide. Numerical simulation by the finite-difference time-domain (FDTD) method demonstrates the
propagation of the broadband pulse. 相似文献
17.
Greg Astfalk 《Applied Physics A: Materials Science & Processing》2009,95(4):933-940
Our focus here is on data communications within IT equipment and in IT data centers. Optical communications is not new. Thus the obvious question is likely; why a paper entitled, “Why optical data communications and why now?”. The reasons are twofold. First, optical data communications is more necessary now than it has ever been in the past. It is not excessive to even consider that it will be required in the not too distant future. Second, the advances in the broad field of photonics and optics have brought optical communications nearly to the point that it can finally cross over the threshold to be less expensive than electronic signaling. In this paper we make the case why we must aggressively pursue optics for data communications at all length scales within the data center. The summarization of this paper is that optical communications is inevitable, and we offer reasons why we believe this is true. 相似文献
18.
We report on the fabrication and characterization of planar and channel waveguides in KTiOPO4 crystals by 6.0 MeV C3+ ion implantation with the dose of 1×1014 ions/cm2. The dark mode spectroscopy of the planar waveguide was measured using a prism coupling arrangement. An increase of the both
n
x
and n
y
refractive indices induced by the annealing after implantation is believed to be responsible for waveguide formation. The
bright near-field intensity distribution of the transverse-electric and transverse-magnetic modes in the annealed channel
waveguide was collected and studied by end-coupling method. 相似文献
19.
C.-T. Zheng C.-S. Ma X. Yan X.-Y. Wang D.-M. Zhang 《Applied physics. B, Lasers and optics》2009,96(1):95-103
By using the coupled mode theory, electro-optic modulation theory, conformal transforming method and image method, the structure
is designed, the parameters are optimized, and the characteristics are analyzed for a polymer directional coupler electro-optic
switch with two-section reversed electrodes. Simulation shows that the designed device exhibits excellent switching functions.
Under the operation wavelength of 1550 nm, the electro-optic coupling region length is 4751 μm, the cross-state and bar-state
voltages are about 1.22 and 2.65 V, and the insertion loss and crosstalk are less than 2.21 and −30 dB, respectively. By slightly
adjusting the state voltages, the blight of the fabrication errors on the switching characteristics can be easily eliminated.
The calculation results of the presented technique are in good agreement with those of the beam propagation method (BPM). 相似文献
20.
W. Brückner B. Cujec H. Döbbeling K. Dworschak H. Kneis S. Majewski M. Nomachi S. Paul B. Povh R. D. Ransome T. -A. Shibata M. Treichel Th. Walcher 《Zeitschrift für Physik A Hadrons and Nuclei》1991,339(3):367-377
Thep¯ p cross sections at low energies are analysed in the framework of the optical model. It is shown that the annihilation range is closely related to the size of the proton as measured in electromagnetic and hadronic interactions. At larger distances thep¯ p interaction has the similar character as the NN one. 相似文献