1. |
- Ahmed, Jawwad, et al.
(författare)
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A Dynamic Bulk Provisioning Framework for Concurrent Optimization in PCE-Based WDM Networks
- 2012
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Ingår i: Journal of Lightwave Technology. - : IEEE. - 0733-8724 .- 1558-2213. ; 30:14, s. 2229-2239
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Tidskriftsartikel (refereegranskat)abstract
- A centralized network control and management plane, such as the one based on a path computation element (PCE), is highly beneficial in terms of resource optimization in wavelength division multiplexing optical networks. Benefits of centralized provisioning are even more evident when connection requests are provisioned in batches, i.e., they allow a better use of network resources via concurrent optimization. In this study, a dynamic bulk provisioning framework is presented with the objective of optimizing the use of network resources that also presents, as an additional benefit, the ability to yield a reduction of the control plane overhead. The rationale behind the proposed framework is based on a mechanism in which the PCE client is allowed to bundle and simultaneously send multiple labeled switch path (LSP) requests to the PCE where, in turn, several bundles can be concurrently processed together as a single bulk. From the network deployment perspective, a PCE-based network architecture is proposed to practically realize this approach. For dynamic bulk provisioning of optical LSP requests, a time-efficient integer linear programming (ILP) model (LSP BP ILP) is presented to minimize the request blocking, the network resource consumption, and the network congestion. In addition, a heuristic based on a greedy randomized adaptive search procedure (GRASP), namely LSP_BP_GRASP, is also proposed as a scalable alternative. The presented results demonstrate significant advantages of the proposed PCE bulk provisioning framework based on concurrent optimization in terms of reduced blocking probability and control overhead when compared with conventional dynamic connection provisioning approaches processing a single connection request at a time.
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2. |
- Björk, Gunnar, et al.
(författare)
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Proposed Implementation of "Non-Physical" Four-Dimensional Polarization Rotations
- 2016
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Ingår i: Journal of Lightwave Technology. - : IEEE. - 0733-8724 .- 1558-2213. ; 34:14, s. 3317-3322
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Tidskriftsartikel (refereegranskat)abstract
- Recently one of us proposed a new formalism for modeling electromagnetic wave transformations for coherent communication using a real, four-vector description instead of the conventionally used Jones calculus or the Mueller matrices. The four-vector can then handle all superpositions of two orthogonal polarization basis and two orthogonal time bases (e.g., the in-phase and quadrature phase). In developing this formulation it was found that to provide a general but minimal framework for such rotations, it is natural to divide the six generators of four-dimensional (4d) rotations into two groups of three generators, the right-and the left-isoclinic matrices. Of the six transformations these generators define, it was furthermore found that four of them are readily implemented by linear optical components, while two of then were impossible to implement by such means. In this paper, we detail the reason these two "unphysical" rotations cannot be implemented with linear optics. We also suggest how they can be implemented, but at a cost in the signal-to-noise ratio, and give this minimum cost.
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4. |
- Campi, Roberta, et al.
(författare)
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Highly reliable and high-yield 1300-nm InGaAlAs directly modulated ridge fabry-Perot lasers, operating at 10-gb/s, up to 110°C, with constant current swing
- 2006
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 24:1, s. 143-149
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Tidskriftsartikel (refereegranskat)abstract
- Transceivers for 300-m multimode links, based on a serial 10-Gb/s laser source and incorporating a receiver based on electronic dispersion compensation (EDC), are creating the first high-volume application for a 10-Gb Fabry-Perot (FP). A highly reliable and high-yield uncooled ridge FP laser is presented. The device shows excellent power characteristics in the 25 divided by 150 degrees C temperature range with very high To (95 K in the temperature range 0 divided by 85 C and still 78 K at 150 degrees C). Outstanding dynamic performances are also shown: 6 dB of extinction ratio can be achieved up to 110 degrees C by using a constant current swing of 50 mA. Because of their enhanced performances, these devices have enabled single temperature setting of the optical module, leading to a significant test cost reduction.
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5. |
- Carlsson, C., et al.
(författare)
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Analog modulation properties of oxide confined VCSELs at microwave frequencies
- 2002
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 20:9, s. 1740-1749
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Tidskriftsartikel (refereegranskat)abstract
- Motivated by the need for affordable, high-performance fiber-optic microwave links in fiber-fed microcellular networks and radar systems, we have performed a comprehensive experimental evaluation of the microwave modulation characteristics of high-speed oxide-confined vertical cavity surface emitting lasers (VCSELs) emitting at 840 inn. VCSELs with different oxide aperture diameters, including both single- and multimode lasers, have been used to track the dependence on modal behavior. The study includes both static and dynamic characteristics, with an emphasis on those of major importance for analog modulation. This includes the small-signal modulation response (S-11 and S-21), the relative intensity noise (RIN), and the intermodulation distortion. From this, we determine the spurious free dynamic range, the impedance characteristics, and the speed limitations.
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6. |
- Cavdar, Cicek, 1977-, et al.
(författare)
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Shared-Path Protection With Delay Tolerance (SDT) in Optical WDM Mesh Networks
- 2010
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 28:14, s. 2068-2076
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Tidskriftsartikel (refereegranskat)abstract
- Optical wavelength-division-multiplexing (WDM) networks have emerged as an ideal backbone for the dynamic transport of bandwidth-intensive applications. Most emerging applications require end-to-end survivable connections to be set up for specific time durations that have sliding or fixed setup times (such as IPTV, grid computing backup storage). It is critical for the development of future network infrastructure that user-centric, dynamic, and end-to-end management and control mechanisms are devised to bridge the gap between the transport capacity and the needs of new applications at the customer edges. In this paper, we study the problem of dynamic provisioning of user-controlled connection requests that have specified holding times and delay tolerances. Delay tolerance is a measure of customer patience, and it is defined as the duration a connection request can be held until it is set up. A connection that cannot be established at the instant of its request could potentially be set up in the remaining duration of its delay tolerance. In this study, different dynamic scheduling algorithms are developed and compared by giving priority to connections according to their arrival rates, delay tolerances, and holding times. Using a mathematical model for impatient requests and simulation experiments, we show that delay tolerance flexibility in the traffic model provides a reduction of up to 50% on blocking probability, without the use of extra backup capacity.
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7. |
- Cen, Min, et al.
(författare)
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Advanced Fault-Monitoring Scheme for Ring-Based Long-Reach Optical Access Networks
- 2017
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Ingår i: Journal of Lightwave Technology. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0733-8724 .- 1558-2213. ; 35:10, s. 1876-1886
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel fiber fault-monitoring system for long-reach optical access networks based on a transmission-reflection analysis approach. By launching an un-modulated continuous-wave optical signal into the feeder ring and measuring the transmitted and reflected/backscattered optical powers, the proposed monitoring scheme is able to detect, identify, and localize any major fault (covering both reflective and nonreflective events) with a good spatial accuracy (<= 10 m) and a high detection speed (3 s). Both experimental and simulation results have demonstrated that the proposed system provides fiber monitoring functionality better than that obtained by the conventional methods.
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8. |
- Chacinski, Marek, et al.
(författare)
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Monolithically Integrated 100 GHz DFB-TWEAM
- 2009
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 7:16, s. 3410-3415
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Tidskriftsartikel (refereegranskat)abstract
- A monolithically integrated distributed feedback (DFB) laser and traveling-wave electro-absorption modulator (TWEAM) with >= 100 GHz -dBe bandwidth suitable for Non-return-to-zero (NRZ) operation with on-off keying (OOK) is presented. The steady-state, small-signal modulation response, microwave reflection, chirp characteristic, and both data operation and transmission were investigated. The DFB-TWEAM was found to be an attractive candidate for future short distance communication in high bitrates systems.
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9. |
- Che, D., et al.
(författare)
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200-Gb/s Direct Modulation of a 50-GHz Class Laser with Advanced Digital Modulations
- 2021
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers Inc.. - 0733-8724 .- 1558-2213. ; 39:3, s. 845-852
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Tidskriftsartikel (refereegranskat)abstract
- Directly modulated lasers (DML) dominate the short reach optical interconnect market. For years, the bandwidth of commercial DMLs has been limited to a level of 25 GHz, which can support a speed up to around 100 Gb/s via advanced modulations like Nyquist-shaped 4-ary pulse amplitude modulation (PAM-4), carrier-less amplitude phase (CAP) modulation, subcarrier multiplexing, and discrete multitone (DMT). To scale with the capacity evolution of interconnect applications, it is in urgent demand to develop DMLs operated at 50G class and even beyond. In this article, we exploit a newly designed 50G-class short-cavity distributed Bragg reflector (DBR) laser, called the two-κ DBR laser, and demonstrate its capability of supporting 200 Gb/s per wavelength direct modulation and direct detection transmissions. Combining high-speed electronics with the 50G-class DML, we demonstrate a variety of advanced digital modulations including Nyquist-shaped 100-GBaud PAM-4, 80-GBaud PAM-8, and 50-GHz DMT signals, with the maximum net bit rate of 236 Gb/s. The DML exhibits an ultra-low chirp parameter of 1.0, which enables isolator-free operation and dispersion-tolerant transmission over tens of kilometers at O-band.
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10. |
- Chen, D. R., et al.
(författare)
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High-Resolution Strain/Temperature Sensing System Based on a High-Finesse Fiber Cavity and Time-Domain Wavelength Demodulation
- 2009
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 27:13, s. 2477-2481
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Tidskriftsartikel (refereegranskat)abstract
- A high-resolution strain/temperature sensing system based on a fiber Bragg grating-Fabry-Perot cavity (FBG-FPC) and a wavelength-swept single-longitudinal-mode laser diode (modulated by a sawtooth signal) is proposed. The high-finesse (similar to 627) FBG-FPC formed by two uniform FBGs of high reflectivity (similar to 99.5%) is used both as a strain/temperature sensor and a FPC with ultranarrow (similar to 0.12 pm) transmission bands. Using a photodetector to detect the transmissive light of the laser diode through the FBG-FPC, wavelength demodulation is achieved by mapping wavelength measurement to time measurement. Both strain sensing and temperature sensing with a resolution of 0.11 mu epsilon and 0.014 degrees C, respectively, have been demonstrated.
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