OPTICS 2014 Abstracts


Full Papers
Paper Nr: 21
Title:

HYRA: An Efficient Hybrid Reporting Method for XG-PON Upstream Resource Allocation

Authors:

Panagiotis Sarigiannidis, Georgios Papadimitriou, Petros Nicopolitidis, Emmanouel Varvarigos and Konstantinos Yiannopoulos

Abstract: The dynamic bandwidth allocation (DBA) process in the modern passive optical networks (PONs) is crucial since it greatly influences the whole network performance. Recently, the latest new generation PON (NGPON) standard, known as 10-gigabit-capable passive optical network (XG-PON), standardized by the international telecommunication union telecommunication standardization sector (ITU-T), emerges as one of the most efficient access networking framework to cope with the demanding needs of the fiber to the x (FTTX) paradigm, where x stands for home (FTTH), bulding (FTTB), or curve (FTTC). Motivated by the fact that the ITU-T specifications leave the bandwidth allocation process open for development by both industry and academia, we propose a novel DBA scheme for effectively delivering data in the upstream direction. Our idea is based on a subtle suggestion induced by the XG-PON specifications; each developed DBA method should combine both status reporting (SR) and traffic monitoring (TM) techniques. This means that a XGPON framework should be cognitive enough in order to be able either to request bandwidth reporting from the connected users or estimate users’ bandwidth demands or both. In this article we cover this gap by proposing a robust learning from experience method by utilizing a powerful yet simple tool, the learning automata (LAs). By combining SR and TM methods, the proposed hybrid scheme, called hybrid reporting allocation (HYRA), is capable of taking efficient decisions on deciding when SR or TM method should be employed so as to maximize the efficacy of the bandwidth allocation process. Simulation results reveal the superiority of our scheme in terms of average packet delay offering up to 33% improvement.

Paper Nr: 23
Title:

On the Prediction of EPON Traffic Using Polynomial Fitting in Optical Network Units

Authors:

I. Mamounakis, K. Yiannopoulos, G. Papadimitriou and E. Varvarigos

Abstract: We propose a traffic prediction algorithm that reduces the packets delay in Ethernet Passive Optical Networks (EPONs). The algorithm relies on Multi-Point Control Protocol (MPCP) message and traffic monitoring at the Optical Network Units (ONUs) and utilizes the monitoring information to predict the accumulated burst size using higher order least-mean-square polynomial approximations. The simulation of the algorithm shows that it achieves a delay improvement of over 30% without any further modification in the communication and bandwidth assignment procedure of the EPON.

Short Papers
Paper Nr: 6
Title:

Multiclass Multiserver Service Differentiation in Optical Flow Switched Networks

Authors:

Ujjwal Arora, Ejaz Aslam Lodhi and Akash Tayal

Abstract: In this paper we wish to analyze the scheduling policy of Optical Flow Switching (OFS) network w.r.t the multiclass priority queue. OFS is an exciting new switching technique which can transfer Terabytes of data in a fraction of seconds, The exquisiteness of OFS is that no buffering and processing is involved at any intermediate routes. Using priority queuing, the flow w.r.t multiclass for multiserver QoS is implemented. We develop the Multiclass priority model with non-pre-emptive model (with no forced termination) to evaluate the performance of the Multiclass Multiserver supported OFS network using the multiclass priority queue. This work presents an entirely new dimension to the Queuing at Access Nodes. Extensive results obtained show the significant change in total and average waiting time as the number of servers is increased. On the other hand, as the priority of the class decreases, the average waiting time also increases.

Paper Nr: 14
Title:

Equalisation of Measured Optical MIMO Channels

Authors:

André Sandmann, Andreas Ahrens and Steffen Lochmann

Abstract: Within the last years multiple-input multiple-output (MIMO) transmission has reached a lot of attention in the optical fibre community. Theoretically, the concept of MIMO is well understood. However, practical implementations of optical components are in the focus of interest for further computer simulations. That’s why in this contribution the specific impulse responses of the (2×2) MIMO channel, including a 1.4 km multi-mode fibre and optical couplers at both ends, are measured for operating wavelengths of 1326 nm and 1576 nm. Since semiconductor diode lasers, capable of working at different wavelengths, are used for the characterization of the underlying optical MIMO channel, inverse filtering is needed for obtaining the respective impulse responses. However, the process of inverse filtering also known as signal deconvolution is critical in noisy environments. That’s why different approaches such as Wiener and parametric filtering are studied with respect to different optimization criteria. Using these obtained impulse responses a baseband MIMO data transmission is modelled. In order to create orthogonal channels enabling a successful transmission, a MIMO zero forcing (ZF) equaliser is implemented and analysed. Our main results given as an open eye-diagram and calculated bit-error rates show the successful implementation of the MIMO transmission system.

Paper Nr: 18
Title:

On the Impact of the Clipping Techniques on the Performance of Optical OFDM

Authors:

João Guerreiro, Rui Dinis and Paulo Montezuma

Abstract: Recently, OFDMmodulations are being considered for both optical fiber and wireless optical communications, specially due to their efficiency to combat the inter-symbol interference. Between the modifications of the standard OFDMthat meet the requirements of the incoherent OFDMoptical communications such as the ones that consider intensity modulation/direct detection, the asymmetric clipping optical OFDM and the DC biased optical OFDM techniques are the most popular but both involve an asymmetric clipping operation. Therefore, due to the high sensitivity of OFDM signals to nonlinearities, the nonlinear distortion effects introduced by the asymmetric clipping in the form of in and out-band-distortion should not be neglected. In fact, in order to address the performance of such systems, these distortion effects must be accurately characterized. In this work, by making use of a Gaussian approximation, we study analytically the impact of the asymmetric clipping in the performance of optical OFDM techniques by deriving theoretical expressions for the power spectral density and for the distortion at the subcarrier level, which is a key step to understand the potential performance of these systems.

Paper Nr: 20
Title:

QAMO: QoS Aware Multipath-TCP Over Optical Burst Switching in Data Centers

Authors:

Sana Tariq and Mostafa Bassiouni

Abstract: The rapid advancement in cloud computing is leading to a promising future for shared data centers hosting diverse applications. These applications constitute a complex mix of workloads from multiple organizations. Some workloads require small predictable latency while others require large sustained throughput. Such shared data-centers are expected to provide potential service differentiation to client’s individual flows. This paper addresses two important issues in shared data centers: bandwidth efficiency and service differentiation based on QoS (Quality of Service). We first evaluate the multipath-TCP (MPTCP) protocol over an OBS (Optical burst switching) network for improved bandwidth utilization in dense interconnect datacenter networks. We next present a simple and efficient ‘QoS aware MPTCP over OBS’ (QAMO) algorithm in datacenters. Our experimental results show that Multipath-TCP improves throughput over an OBS network while the QAMO algorithm achieves tangible service differentiation without impacting the throughput of the system.

Paper Nr: 24
Title:

Research on Routing and Wavelength/Subcarrier Assignment Algorithm Based on Layered-graph Model in Optical Satellite Networks

Authors:

Yuanyue Guo, Dongjin Wang and Falin Liu

Abstract: In optical satellite networks with multi-wavelengths and multi-subcarriers, two-level switching mode replace single wavelength switching, achieving better flexibility and network performance with its disadvantages of more complex routing and network resource allocation. Based on subcarrier layered-graph (SL-G), a novel dynamic routing and wavelength/subcarrier assignment (RWSA) algorithm is proposed to find the shortest path with limited costs in the corresponding layered-graph. By defining different edge cost functions in SL-G, centralized resource allocation strategy and decentralized resource allocation strategy in dynamic RWSA are analysed for optical satellite networks with different types of constellations. Simulation results demonstrate that, no matter whether optical satellite networks has single constellation with uniform wavelength distribution or hybrid constellations with non-uniform wavelength distribution, the proposed RWSA algorithms are superior to traditional routing and wavelength assignment algorithms with lower network blocking probability.

Paper Nr: 27
Title:

Initial Alignment Scheme and Tracking Control Technique of Free Space Optics Laser Beam

Authors:

Takeshi Tsujimura, Shigeki Muta, Yuichiro Masaki and Kiyotaka Izumi

Abstract: This paper describes the laser beam alignment techniques for free space optical communication. Bilateral laser transmission system is designed between two active free-space-optical apparatuses, which are equipped with galvanic scanners, E/O and O/E converters and are able to control laser beam discharging directions. Two alignment strategies are proposed with regard to the transient and steady state of optical signal transmission. Search method for initial alignment is established based on the Gaussian beam optics, and a tracking control system is constructed for laser beam to maintain stable telecommunication between roaming transmission equipments. Experiments reveal that the proposed techniques enable the free space optics system to locate the target receiver and to pursue the unstable transmission apparatus.

Posters
Paper Nr: 13
Title:

Receiver Design for an Optical MIMO Testbed

Authors:

Heidi Köhnke, Robert Schwinkendorf, Sebastian Daase, Andreas Ahrens and Steffen Lochmann

Abstract: Within the last years multiple-input multiple-output (MIMO) systems have attracted a lot of attention in the optical fibre community. Although the theoretical background of MIMO transmission is well understood, there is still a need for practical investigations regarding mode combining, mode maintenance and mode splitting. Since these components represent an essential part of an optical MIMO system, in this work a (2×2) MIMO testbed using fusion couplers and a multi-mode fibre (MMF) length of 1.9 km is set up for an operating wavelength of 1326 nm. Together with the MIMO receiver-side signal processing the successful transmission of parallel data streams is presented.

Paper Nr: 17
Title:

Research of Cable Identification Method Based on Single Fiber

Authors:

Qiang Sun and Qifu Wu

Abstract: Optical cable identification plays a very important role in cable maintenance and fault detection. In this paper, a new cable identification method based on optical fiber end reflection is proposed. Based on the theory of optical fiber sensor and phase modulation technology, single fiber optical cable identification is effectively achieved. System composition of this method is introduced in this paper. According to light interference principle, the expression of phase change when signal acts on fiber sensor is deduced; the relationship between redundant optical fiber and the system output signal is analyzed. The reasonable redundant fiber length is obtained by Matlab simulation, and the feasibility of the method is verified by experiment. Compared with other cable identification method, experimental results show that the single fiber optical cable identification has greatly improved in detection sensitivity and low maintenance time and costs.

Paper Nr: 22
Title:

Delay-Aware Dynamic Wavelength Bandwidth Allocation in Time- and Wavelength-Division-Multiplexed Passive Optical Network

Authors:

Junsu Kim, Yong-Kyu Choi, Han Hyub Lee and Chang-Soo Park

Abstract: Most research works related to dynamic wavelength bandwidth allocation in a time- and wavelength-division–multiplexed passive optical network are based on bin packing algorithm and present many advantages in terms of bandwidth utilization and energy efficiency. However, delay performance can be significantly degraded by frequent wavelength changes. In this paper, we propose a delay-aware dynamic wavelength bandwidth allocation algorithm. First, we theoretically analyze queuing delay corresponding to the tuning time, decision cycle, and the number of optical network units. And then, we show that the queuing delay is decreased by setting the limit value of the number of optical network units in a wavelength channel. In addition, we derive the threshold ratio of the tuning time to the decision cycle as 0.004.

Paper Nr: 26
Title:

Mid-Infrared Supercontinuum Generation in an AsSe2-As2S5 Hybrid Microstructured Optical Fiber

Authors:

Tonglei Cheng, Yasuhire Kanou, Dinghuan Deng, Xiaojie Xue, Morio Matsumoto, Takashi Misumi, Takenobu Suzuki and Yasutake Ohishi

Abstract: A four-hole AsSe2-As2S5 hybrid microstructured optical fiber (HMOF) with a large refractive index difference is fabricated by the rod-in-tube drawing technique. The core and the cladding are made from the AsSe2 glass and As2S5 glass, respectively. The propagation loss is 1.2 dB/m and the nonlinear coefficient is 4.937×104 km-1W-1at ~3000 nm. Zero dispersion wavelength (ZDW) of the HMOF is 3380 nm. Supercontinuum (SC) generation in the HMOF is investigated by pumping a 2 cm-long AsSe2-As2S5 HMOF with the wavelengths of 3062, 3241 and 3389 nm from a tunable optical parametric oscillator (OPO) system. Broadband mid-infrared SC generation with the spectrum from 1256 to 6385 nm is obtained with the peak power of 1337 kW at the wavelength of 3389 nm.