Vol. 6, No. 11 / November 2007 / JOURNAL OF OPTICAL NETWORKING 1244

Photonics in Switching: introduction to thefeature issue

Lena Wosinska

Royal Institute of Technology (KTH) / ICT Sweden

Madeleine Glick

Intel Research

Published October 18, 2007 (Doc. ID 88189)

This issue of the Journal of Optical Networking focuses on the technology and architectureof optical switching nodes, including the architectural and algorithmic aspects of high-speedoptical networks.

Technologies based on dense wavelength division multiplexing (DWDM) systems allowdata transmission with bit rates of Tb/s on a single fiber. To facilitate this enormous transmis-sion volume, high-capacity and high-speed network nodes become inevitable in the opticalnetwork.

WDM switching, optical burst switching (OBS), and optical packet switching (OPS) arepromising technologies for harnessing the bandwidth of WDM optical fiber networks in ahighly flexible and efficient manner. As a number of key optical component technologies ap-proach maturity, photonics in switching is becoming an increasingly attractive and practicalsolution for the next generation of optical networks.

The feature attracted 38 submissions, from which 18 were accepted for publication afterrevisions. The accepted contributions addressed the following research areas:

• Optical circuit switching: OCS node architecture and performance, OCS network de-sign and analysis.

• Optical packet switching: OPS networks and nodes, including contention resolution,switch fabric, and optical memory

• Optical burst switching: quality of service support in OBS network

The following papers are related to OCS node architectures, performance, and networks.

In "ZL-switching matrix: an optimal scalable free-space strictly nonblocking two-dimensional optical cross connect architecture," S. S. Abdallah and J. T.-W. Yeow proposea scalable 2D switching matrix for large-scale optical switches.

"Comparative study of existing OADM and OXC architectures and technologies from thefailure behavior perspective," by P. G. Arbués, C. Mas Machuca, and A. Tzanakaki presentsa comparison of different OCS node architectures and technologies from the failure behaviorpoint of view.

In "Optical cross-connect architectures with the ability to tailor transmission properties,"C. Matrakidis, C. (T.) Politi, and A. Stavdas propose the tunable dispersion compensatingdevices as switching elements in order to achieve the optimum balance between chromaticdispersion and nonlinearity in an optical core network.

To meet the fault tolerance and ensure high availability in the presence of faults in ahigh-performance computing system nD-RAPID (reconfigurable and scalable all-photonicinterconnect for distributed and parallel systems) a multidimensional optoelectronic archi-tecture was proposed. The fault-tolerant routing algorithm provides optimum performance in

© 2007 Optical Society of America

Vol. 6, No. 11 / November 2007 / JOURNAL OF OPTICAL NETWORKING 1245

the absence of faults and shows minimal degradation in the presence of faults and can toler-ate a reasonable number of faults. In "nD-RAPID: a multidimensional scalable fault-tolerantoptoelectronic interconnection for high-performance computing systems," by C. Kochar, A.Kodi, and A. Louri, the proposed on-board switching mechanism dynamically reconfiguresitself to reroute packets around faulty links.

Obviously, the innovative optical-switch fabrics must meet performance goals. This sub-ject is discussed in "Bit error rate and cross-talk performance in optical cross connect withwavelength converter," where M. S. Islam and S. P. Majumder present an analytical approachfor modeling cross talk and evaluating the bit error rate (BER) performance in a WDM net-work for link with optical cross connect (OXC). Factors affecting the magnitude of crosstalk in the OXC are investigated and identified, and the effects of OXC-induced cross talkon the BER performance are evaluated at a bit rate of 10 Gbits/s.

In "Cost effectiveness of protection schemes for IP-over-WDM networks," N. S. C. Cor-reia and M. C. R. Medeiros examine the cost related to IP protection and WDM sharedprotection.

"Efficient use of protection bandwidth and switching resources in optical WDM net-works," by E. D. Manley, H. S. Hamza, and J. S. Deogun proposes a method for efficientresource utilization in terms of both bandwidth and switching resources in protected opticalWDM networks.

In "Conversion cascading constraint-aware adaptive routing for WDM optical networks,"X. Gao, M. A. Bassiouni, and G. Li examine the negative impact of wavelength conversioncascading on the performance of all-optical routing.

In "Design and analysis of strictly nonblocking WDM optical-switching networks," by H.S. Hamza and J. S. Deogun, two novel strictly nonblocking crossbar-like WDM networksare proposed and used to design two new classes of Clos-type switching networks. Analysisof hardware complexity shows that the proposed designs can achieve up to 30% reduction inoverall cost compared with other WDM switching networks while using a smaller numberof stages.

In "Plug and play optical nodes: network functionalities and built-in fiber characterizationtechniques," I. Cerutti, A. Fumagalli, R. Hui, P. Monti, Alberto Paradisi, and M. Tacca pointout the challenges for networks employing plug and play optical nodes and present solutionsbased on plug and play optical node hardware architectures.

Optical packet switching networks and nodes are addressed in the following papers.

"Time-to-live decrementing scheme in optical packet switching," by Y. Ling, K. Qiu, Y.Pang, and W. Zhang proposes a novel scheme for decrementing one time-to-live pulse basedon an asymmetric Mach–Zehnder interferometer and a Fabry–Perot semiconductor opticalamplifier.

In "Prioritized retransmission in slotted all-optical packet-switched networks," by A. G.P. Rahbar and O. Yang, an all-optical slotted packet-switched network interconnected bybufferless all-optical switches with contention-based operation is considered with the objec-tive to reduce the cost of the expensive contention resolution hardware.

In "Combining contention resolution schemes in WDM optical packet switches with mul-tifiber interfaces," by G. Muretto and C. Raffaelli, optical packet switch architectures withmultifiber interfaces are considered to combine space, wavelength, and time-domain con-tention resolution.

Contention resolution in OPS is also addressed in "Comparative study of limited-rangewavelength conversion policies for asynchronous optical packet switching," by K. Dogan,Y. Gunalay, and N. Akar. In this paper an asynchronous optical packet (OP)-switching nodeequipped with a number of limited-range wavelength converters shared per output link isproposed and evaluated. It is shown that the far-conversion policy for which the opticalpacket is switched onto the farthest available wavelength in the tuning range outperforms

© 2007 Optical Society of America

Vol. 6, No. 11 / November 2007 / JOURNAL OF OPTICAL NETWORKING 1246

the other policies we studied.

"Optical loop memory for photonic switching application," by R. Srivastava, R. KumarSingh, and Y. N. Singh proposes architecture for a WDM-based photonic packet switch. Themain advantage of this architecture is that no controlling is required inside the buffer. Packetloss probability and delay are evaluated.

Semiconductor optical amplifiers are often used in optical switching fabrics. Two papersdeal specifically with aspects related to these devices. "Two-wavelength switching with 1550nm semiconductor laser amplifiers," by A. Hurtado and M. J. Adams presents an approachusing two-wavelength switching operation between two signals at different wavelengths us-ing the optical bistability occurring in two different semiconductor laser amplifiers. A theo-retical model is shown to analyze the wavelength switching operation with a novel amplifiertype.

In "Development and fabrication of monolithically integrated optical packet switches,"D. A. Yanson, M. Silver, O. Vassalli, M. Campbell, G. Masterton, S. D. McDougall, and J.H. Marsh report on activities toward realization of fully integrated 1x2, 2x2, and 4x4 cross-point optical switches for WDM-packet-based data networking. Two enabling technologies,quantum-well intermixing and etched turning mirrors, are developed and demonstrated.

Finally, optical burst switching is addressed in "Analysis and design of edge-based con-trollers supporting absolute QoS for optical bursts," by M. Jin and O. W. W. Yang. In thispaper a new edge-based controlling scheme to achieve a guaranteed loss performance foran optical burst flow is presented. The control system does not affect the packet transmis-sion load, which is especially useful for such critical applications as multimedia streams andcan be applied to various networks using different assembly algorithms, signaling protocols,contention resolution methods, or varying network inputs.

© 2007 Optical Society of America