| 1. |
- Acharya, B. S., et al.
(författare)
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Introducing the CTA concept
- 2013
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 43, s. 3-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. (C) 2013 Elsevier B.V. All rights reserved.
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| 2. |
- Feng, Z., et al.
(författare)
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A simplified adaptive modulation scheme for RSOA based DDO-OFDM system using CAZAC precoding
- 2016
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Ingår i: 2016 Optical Fiber Communications Conference and Exhibition, OFC 2016. - Washington, D.C. : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrated a RSOA based DDO-OFDM system using CAZAC precoding. Adaptive modulation has been simply and efficiently performed after CAZAC precoding to improve the sensitivity and overall data rate thanks to the equalized SNR.
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| 3. |
- Feng, Z., et al.
(författare)
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Power efficient optical OFDM transmission with phase modulation and direct detection
- 2016
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Ingår i: 2016 21st OptoElectronics and Communications Conference, OECC 2016 - Held Jointly with 2016 International Conference on Photonics in Switching, PS 2016. - : IEEE conference proceedings. - 9784885523052
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Konferensbidrag (refereegranskat)abstract
- Optical OFDM transmission with phase modulation and direct detection (PMDD) is verified by theoretical derivation and simulation. 26.12-Gb/s PMDD 16QAM-OFDM achieves comparable performance to single sideband IMDD 16QAM-OFDM with half of the optical modulation index.
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| 4. |
- Feng, Zhenhua, et al.
(författare)
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SNR equalized optical direct-detected OFDM transmission with CAZAC equalization
- 2015
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Ingår i: CLEO. - : Optica Publishing Group.
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Konferensbidrag (refereegranskat)abstract
- 50Km SSMF optical direct-detected OFDM transmission with Constant Amplitude Zero Auto Correlation Sequence (CAZAC) equalization is experimentally demonstrated with over 15dB power budget. 2.5dB enhancement in sensitivity has been achieved simultaneously with 3dB PAPR suppression.
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| 5. |
- Feng, Z., et al.
(författare)
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Terabit WSDM optical access network using multicore fibers and advanced modulation formats
- 2015
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Konferensbidrag (refereegranskat)abstract
- We proposed a hybrid wavelength-space division multiplexing (WSDM) optical access network architecture utilizing multicore fibers (MCFs) with advanced modulation formats. As a proof of concept, we experimentally demonstrated a WSDM optical access network with duplex transmission using our developed and fabricated multicore (7-core) fibers and fan-in/fan-out device with 58.7km distance. With QPSK-OFDM modulation format, the aggregation downstream (DS) capacity reaches 250 Gb/s using 5 outer cores and it can be further scaled to 1Tb/s using 16QAM-OFDM. For upstream (US) transmission, wavelengths seeded from DS using the inner core are modulated with DMT signal adapted with the channel conditions and then transmitted back to the OLT through the 6th outer core. As an emulation of high speed mobile backhaul (MB) transmission, IQ modulated PDM-QPSK signal with 48Gb/s per wavelength is transmitted in the inner core of MCF and coherently detected in the OLT side. Both DS and US optical signal exhibit acceptable performance with sufficient power budget.
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| 6. |
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| 7. |
- Wang, R., et al.
(författare)
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Programmable fiber-based in-band OSNR monitoring for flexgrid coherent optical communication system
- 2015
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Konferensbidrag (refereegranskat)abstract
- With the rapid development of ultra-dense large capacity coherent WDM optical communication networks, the monitoring of in-band optical signal-to-noise ratio (OSNR) plays an essential role to ensure signal qualities. Different from the classic polarization-nulling method, we proposed and experimentally demonstrated a novel fiber-based programmable in-band OSNR monitoring method for flexgrid coherent transmission system, the OSNR monitor is based on linearly chirped fiber Bragg grating (LCFBG) and commercial thermal print head (TPH). For the coherent communication system, when the output power of the pre-amplifier at the receiving terminal is constant, degraded OSNR leads to decreased signal power and elevated ASE noise. Therefore, if the central spectrum (signal and in-band noise) is filtered by an ultra-narrow bandwidth optical filter, the output optical power is in proportional to the OSNR value, the influence of the filtered in-band ASE noise will be negligible with relatively high OSNR and the ultranarrow bandpass filter is the key element for this technique. Based on the thermo-optic effect of the LCFBG, we used the in-house developed driver circuits and a LabVIEW based software to implement a programmable ultra-narrow passband optical filter for OSNR monitoring. Linear monitoring range of 9-27dB OSNR values with wavelength ranging from 1530.6 to 1538nm is achieved. The OSNR monitor has advantages of low cost, low insertion loss, large wavelength tunability and compatible with current optical fiber communication system.
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| 8. |
- Zhang, L., et al.
(författare)
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Low-cost in-band OSNR monitoring based on coherent hybrid in CO-OFDM system
- 2015
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Ingår i: CLEO: Science and Innovations, CLEO-SI 2015.
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Konferensbidrag (refereegranskat)abstract
- We proposed and demonstrated a cost-effective in-band optical signal to noise ratio (OSNR) monitoring technique based on coherent hybrid in 20Gb/s CO-OFDM system. Less than 0.5dB monitoring error is achieved with 400MHz balanced photodetector (PD).
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| 9. |
- Bösl, Korbinian, et al.
(författare)
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Common Nodes of Virus-Host Interaction Revealed Through an Integrated Network Analysis
- 2019
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Ingår i: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Viruses are one of the major causes of acute and chronic infectious diseases and thus a major contributor to the global burden of disease. Several studies have shown how viruses have evolved to hijack basic cellular pathways and evade innate immune response by modulating key host factors and signaling pathways. A collective view of these multiple studies could advance our understanding of virus-host interactions and provide new therapeutic perspectives for the treatment of viral diseases. Here, we performed an integrative meta-analysis to elucidate the 17 different host-virus interactomes. Network and bioinformatics analyses showed how viruses with small genomes efficiently achieve the maximal effect by targeting multifunctional and highly connected host proteins with a high occurrence of disordered regions. We also identified the core cellular process subnetworks that are targeted by all the viruses. Integration with functional RNA interference (RNAi) datasets showed that a large proportion of the targets are required for viral replication. Furthermore, we performed an interactome-informed drug re-purposing screen and identified novel activities for broad-spectrum antiviral agents against hepatitis C virus and human metapneumovirus. Altogether, these orthogonal datasets could serve as a platform for hypothesis generation and follow-up studies to broaden our understanding of the viral evasion landscape.
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| 10. |
- Dong, H., et al.
(författare)
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Generalized Mueller matrix method for polarization mode dispersion measurement in a system with polarization-dependent loss or gain
- 2006
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 14:12, s. 5067-5072
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Tidskriftsartikel (refereegranskat)abstract
- A generalized Mueller matrix method (GMMM) is proposed to measure the polarization mode dispersion (PMD) in an optical fiber system with polarization-dependent loss or gain (PDL/G). This algorithm is based on the polar decomposition of a 4×4 matrix which corresponds to a Lorentz transformation. Compared to the generalized Poincaré sphere method, the GMMM can measure PMD accurately with a relatively larger frequency step, and the obtained PMD data has very low noise level.
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| 11. |
- Dong, H., et al.
(författare)
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Quasi-monochromatic fiber depolarizer and its application to polarization-dependent loss measurement
- 2006
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Ingår i: Optics Letters. - : Optical Society of America. - 0146-9592 .- 1539-4794. ; 31:7, s. 876-878
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically derive the relationship between the degrees of polarization (DOPs) of input and output for an optical component with polarization-dependent loss (PDL) and birefringence. Based on the theoretical result, we propose a novel depolarizer for quasi-monochromatic light that can depolarize a fully polarized light with a 50 MHz50 MHz linewidth to less than 0.2% in the DOP. The depolarized light is then used to measure PDL in a single-mode optical fiber link. To the best of our knowledge, our new PDL measurement method is significantly faster than all known methods. Experimental results show excellent agreement with other methods.
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| 12. |
- Lin, Rui, et al.
(författare)
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An Ultra-dense Optical Comb Based DWDM-OFDM-PON System
- 2014
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Konferensbidrag (refereegranskat)abstract
- We proposed and demonstrated an ultra-dense optical comb based DWDM-OFDM-PON scheme. At the optical line terminal (OLT), a cost-effective optical frequency comb generator (OFCG) is proposed and achieved as the multi-wavelength optical source. The OFCG is capable to provide multiple channels with reconfigurable wavelength spacing for ultra-dense WDM-PON based access network. In our scheme, OFDMsignal with multi-level modulation will be encoded into the OFCG lines for the downstream transmission to enhance the spectral efficiency while the OFDM signal will be remodulated by OOK data for the upstream transmission due to its ease of implementation in optical network unit (ONU) side. In experiments, we demonstrated that 10 optical lines with 25 GHz channel spacing are generated and they were modulated by 2.5-GB/s QPSK-OFDM for the downlink signal transmission. We also demonstrated that the multiple wavelengths from the OFCG.
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| 13. |
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| 14. |
- Lin, Rui, et al.
(författare)
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Palm-shaped spectrum generation for dual-band millimeter wave and baseband signals over fiber
- 2016
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Ingår i: Optics Communications. - : Elsevier. - 0030-4018 .- 1873-0310. ; 367, s. 137-143
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Tidskriftsartikel (refereegranskat)abstract
- In order to offer abundant available bandwidth for radio access networks satisfying future 5G requirements on capacity, this paper proposes a simple and cost-effective palm-shaped spectrum generation scheme that can be used for high capacity radio over fiber (RoF) system. The proposed scheme can simultaneously generate an optical carrier used for upstream and two bands of millimeter wave (MMW) that are capable of carrying different downstream data. The experiment results show that the proposed palm-shaped spectrum generation scheme outperforms optical frequency comb (OFC) based multi-band MMW generation in terms of upstream transmission performance. Furthermore, simulation is carried out with different dual-band MMW configurations to verify the feasibility of using the proposed spectrum generation scheme in the RoF system.
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| 15. |
- Wang, R., et al.
(författare)
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Electrically programmable all-fiber structured second order optical temporal differentiator
- 2015
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Ingår i: IEEE Photonics Journal. - 1943-0655. ; 7:3
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Tidskriftsartikel (refereegranskat)abstract
- We propose and experimentally demonstrate an electrically programmable second order optical temporal differentiator (OTD) based on linearly chirped fiber Bragg grating (LCFBG) and digital thermal print head (TPH). For the high-speed optical signal with 25-GHz repetition rate, an efficient second-order OTD has been achieved for arbitrary wavelength and bandwidth with the software-defined TPH configurations. By optimizing the thermooptic effect induced optical phase change in the LCFBG, the central wavelength of the differentiator can be reconfigured flexibly from 1543.5 to 1561.7 nm, with a step size of 0.114 nm. By dynamically controlling the heating elements bonded with the LCFBG, optical pulses with 0.55- and 0.8-nm 3-dB bandwidths have been successfully processed with acceptable deviation compared with the theoretical calculations.
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| 16. |
- Xia, L., et al.
(författare)
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Tunable and switchable fiber ring laser among four wavelengths with ultranarrow wavelength spacing using a quadruple-transmission-band fiber bragg grating filter
- 2006
-
Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 18:19, s. 2038-2040
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Tidskriftsartikel (refereegranskat)abstract
- Four pi-phase shifts are introduced in a uniform fiber Bragg grating (FBG) structure to realize a quadruple-transmission-band filter with ultranarrow 40-pm wavelength spacing. Four separate single-wavelength lasings at 1552.60, 1552.63, 1552.67, and 1552.71 nm, and three pairs of dual-wavelength lasings among above four wavelengths, are achieved stably by incorporating the quadruple-transmission-band FBG filter in a fiber ring cavity with a tunable uniform FBG acting as coarse frequency selection. This new kind of laser will be very useful in applications requiring closely spaced and tunable single- or dual-wavelength components.
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| 17. |
- Yan, M., et al.
(författare)
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Air guiding with honeycomb photonic bandgap fiber
- 2005
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Ingår i: IEEE Photonics Technology Letters. - : IEEE. - 1041-1135 .- 1941-0174. ; 17:1, s. 64-66
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Tidskriftsartikel (refereegranskat)abstract
- We notice that honeycomb cladding was overlooked for air-guiding photonic bandgap fiber design. Air-silica honeycomb cladding is shown in this letter to be able to guide light in a slightly large-sized hollow core, with a reasonably wide bandwidth (/spl sim/200 nm). Noncircular air-hole shape is also explored for air-guiding honeycomb fiber design.
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| 18. |
- Yan, M., et al.
(författare)
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Analysis of perturbed Bragg fibers with an extended transfer matrix method
- 2006
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 14:7, s. 2596-2610
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Tidskriftsartikel (refereegranskat)abstract
- We introduce an extended transfer matrix method (TMM) for solving guided modes in leaky optical fibers with layered cladding. The method can deal with fibers with circular but nonconcentric material interfaces. Validity of the method is verified by two full-vector numerical methods. The TMM is then used to investigate the guidance property of perturbed Bragg fibers. Our analysis reveals that the core modes will interact with each other when a perturbed Bragg fiber has only C 1 symmetry. Special attention is paid to the first transverse-electric (TE01) mode, which is found to experience severe degradation around spectral regions where its dispersion curve supposedly crosses a transverse-magnetic (TM) or hybrid mode.
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| 19. |
- Yan, M., et al.
(författare)
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Antiguiding in microstructured optical fibers
- 2004
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 12:1, s. 104-116
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Tidskriftsartikel (refereegranskat)abstract
- Antiguiding, as opposed to positive index-contrast guiding (or index-guiding), in microstructured air-silica optical fibers is shown to have a significant influence on the fiber’s transmission property, especially when perturbations exist near the defect core. Antiguided modes are numerically analyzed in such fibers by treating the finite periodic air-silica composite (including the central defect) as the core and outer bulk silica region as the cladding. Higher-order modes, which can couple energy from the fundamental mode in the presence of waveguide irregularities, are predicted to be responsible for high leakage loss of realistic holey fibers. The modal property of an equivalent simple step-index antiguide model is also analyzed. Results show that approximation from a composite core waveguide to a simple step-index fiber always neglects some important modal characteristics.
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| 20. |
- Yan, M., et al.
(författare)
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Design of air-guiding honeycomb photonic bandgap fiber
- 2005
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Ingår i: Optics Letters. - : Optical Society of America. - 0146-9592 .- 1539-4794. ; 30:5, s. 465-467
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Tidskriftsartikel (refereegranskat)abstract
- We introduce a design procedure for hollow-core photonic bandgap (PBG) fiber with a cladding made of air–silica honeycomb photonic crystal (PC). It is found that air-guiding can be realized in both fundamental and secondary PBG regions of the cladding PC. Dispersion and radiation loss of the fundamental mode for two types of fiber structure are theoretically calculated. The fibers show promising waveguiding ability.
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| 21. |
- Yan, M., et al.
(författare)
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Heterostructured photonic crystal fiber
- 2005
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Ingår i: IEEE Photonics Technology Letters. - : IEEE. - 1041-1135 .- 1941-0174. ; 17:7, s. 1438-1440
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Tidskriftsartikel (refereegranskat)abstract
- We introduce heterostructured photonic crystal fibers whose cladding and core are two lattice-matched photonic crystals (PCs). Confined modes, particularly those due to photonic bandgaps (PBGs) possessed by cladding PC, can be quickly predicted by studying cladding PBG regions and space-filling modes of the core PC. We theoretically demonstrate that PBG-guided modes can be either index-guided or antiguided locally in the core area. Such fibers are expected to have applications in nonlinear optics and sensors.
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| 22. |
- Yan, M., et al.
(författare)
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Hole-assisted multiring fiber with low dispersion around 1550 nm
- 2004
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Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 16:1, s. 123-125
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Tidskriftsartikel (refereegranskat)abstract
- Due to large index contrast between air and silica, many properties of optical fiber unachievable through doping can be realized easily by utilizing air holes. We present a nonzero dispersion-shifted fiber design based on multiring index profile with the assistance of air holes. The proposed fiber exhibits small dispersion values over nearly 100-nm-wide wavelength range with very low dispersion slope. It can have applications in future long-haul optical communication network.
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| 23. |
- Yan, M., et al.
(författare)
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Honeycomb photonic bandgap fiber with a modified core design
- 2004
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Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 16:9, s. 2051-2053
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Tidskriftsartikel (refereegranskat)abstract
- Air-silica honeycomb fiber with a modified core design is introduced. The core has a concentrated high-index region. Such core design helps defect core mode stay in the cladding's photonic bandgap for a longer wavelength range (>1000 nm) as compared to conventional design. We further point out the importance of our core design in reducing the number of defect modes supported by the fiber structure.
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| 24. |
- Yan, M., et al.
(författare)
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Improved air–silica photonic crystal with a triangular airhole arrangement for hollow-core photonic bandgap fiber design
- 2005
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Ingår i: Optics Letters. - : Optical Society of America. - 0146-9592 .- 1539-4794. ; 30:15, s. 1920-1922
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Tidskriftsartikel (refereegranskat)abstract
- We propose an improved photonic crystal (PC) cladding design for existing air-guiding photonic bandgap (PBG) fibers whose cladding airholes are arranged in a triangular lattice pattern. By increasing the sizes of concentrated silica regions in the cladding PC, we can have a larger degree of freedom in controlling the cladding bandgap regions. We predict that a fiber made from this type of cladding would perform better in terms of the PBG-guiding wavelength range, radiation loss owing to finite cladding size, and the ability to avoid surface mode problems.
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| 25. |
- Yu, X., et al.
(författare)
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Coupling coefficient of two-core microstructured optical fiber
- 2006
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Ingår i: Optics Communications. - : Elsevier. - 0030-4018 .- 1873-0310. ; 260:1, s. 164-169
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, coupled-mode theory is applied to a two-core microstructured optical fiber for the first time to calculate the coupling coefficients for different fiber structures by employing a simple effective index model approach. The dependence of the mode coupling properties upon the geometrical parameters of the two-core structures (air-hole arrangement, hole size, and pitch size) and wavelength are evaluated systematically. The effective index coupled-mode theory is compared with the finite-element method based super-mode theory in details and the results show good agreement. The coupling characteristics are proven to be insensitive to the longitudinal strain by considering the photoelastic effects.
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| 26. |
- Yu, X., et al.
(författare)
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Silica-based birefringent large-mode-area fiber with a nanostructure core
- 2008
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 20:1-4, s. 246-248
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructure photonic crystals with two-fold symmetry are introduced into a silica-based fiber core to induce high birefringence between the two nearly orthogonal fundamental modes. We theoretically study and provide our preliminary findings on the birefringence property of such fibers over a large wavelength range. A large-mode-area structure with a typical high birefringence in the order of 10(-1) is easily realized.
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| 27. |
- Yu, X., et al.
(författare)
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Silica-based birefringent large-mode-area fiber with a nanostructure core
- 2008
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Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 20:4, s. 246-248
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructure photonic crystals with two-fold symmetry are introduced into a silica-based fiber core to induce high birefringence between the two nearly orthogonal fundamental modes. We theoretically study and provide our preliminary findings on the birefringence property of such fibers over a large wavelength range. A large-mode-area structure with a typical high birefringence in the order of is easily realized.
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| 28. |
- Yu, X., et al.
(författare)
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Theoretical investigation of highly birefringent all-solid photonic bandgap fiber with elliptical cladding rods
- 2006
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Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 18:11, s. 1243-1245
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically study for the first time the waveguiding properties of an all-solid photonic bandgap fiber with elliptical cladding rods. High birefringence in the order of 10 -3 is easily achievable in such fibers. The contributions of the cladding rod's ellipticity, the lattice ratio of the cladding microstructure as well as the index contrast of two soft glasses to the birefringence are systematically evaluated. The evolutions of birefringence with the structure and material variations show that our highly birefringent fiber design can be tailored.
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