All-optical Label Swapping Research Articles

Terahertz Spoof Surface Plasmonic Logic Gates.

SummaryLogic gates are important components in integrated photonic circuitry. Here, a series of logic gates to achieve fundamental logic operations based on linear interference in spoof surface plasmon polariton waveguides are demonstrated at terahertz frequencies. A metasurface-based plasmonic source is adopted to couple free-space terahertz radiation into surface waves, followed by a funnel-shaped metasurface to efficiently couple the surface waves to the waveguides built on a domino structure. A single Mach-Zehnder waveguide interferometer can work as logic gates for four logic functions: AND, NOT, OR, and XOR. By cascading two such interferometers, NAND and NOR operations can also be achieved. Experimental investigations are supported by numerical simulations, and good agreement is obtained. The logic gates have compact sizes and high intensity contrasts for the output “1” and “0” states. More complicated functions can be envisioned and will be of great value for future terahertz integrated computing.

A survey on all optical label swapping techniques: Comparison and trends

The rapid growth of packet based Internet traffic and big data, associated with interconnected Data Centers (DC) and High Performance Computing (HPC) systems have imposed the need for ultrahigh link capacities and ultrahigh packet switching speeds, at network nodes. In order to overcome these ultrahigh demands, and particularly packet routing and forwarding, All Optical Label Swapping (AOLS) has been considered for many years as an established solution. This survey paper gives an updated and thorough investigation on AOLS technology and trends, based on a vast reference amount of research milestones throughout all this long time era. All types of labeling techniques are presented and compared, and their pros and cons are summarized all together. Moreover, important issues and directions for research are discussed, giving researchers guidelines and motivation for extended investigation.

NUMERICAL ANALYSIS OF THE INSTANTANEOUS AND RELAXED KERR MODEL FOR GENERATION OF THE ALL-OPTICAL LOGIC GATES WITH TRIANGULAR FIBER COUPLER (TFC)

All-optical logic gates can enable many advanced functions such as all-optical bit-pattern recognition, all-optical bit-error rate monitoring, all-optical packet address and payload separation, all-optical label swapping and all-optical packet drop in optical time domain multiplexing (OTDM) networks. Recently, much attention has been given to the influence of the relaxation process (sometimes called the Debye relaxation model) of the nonlinear response because the usual assumption of instantaneous nonlinear response fails for ultrashort pulses and additional contributions coming from nonlinear dispersion and relaxed nonlinearity have to be taken into account. The Kerr–Debye model is a relaxation of the nonlinear Kerr model in which the relaxation coefficient is a finite response time of the nonlinear material. In this paper, we have presented a numerical analysis of the triangular fiber coupler (TFC) for generation of the all-optical logic gates with nonlinear optical (NLO) properties, where we consider the nonlinear effects Kerr group velocity dispersion (GVD) and self-phase modulation (SPM) instantaneous and relaxed (Kerr–Debye model). To implement all-optical logic gates we used TFC of three symmetric configurations [Instantaneous (III), Relaxed (RRR-5 and RRR-9)]. In the instantaneous condition, the TFC is made up of silica optical fibers (with instantaneous response time — indicated by III) and in the relaxed conditions (RRR-5 and RRR-9) the TFC is made up of fibers with delayed response time of around 25 ps (for example, the polymer optical fibers). In our paper, we are interested in the transmission characteristics, the XRatio level (XR (dB)) as a function of the ΔΦ parameter, the normalized time duration (NTD) and the pulse evolution along the TFC and finally to compare the performance of all-optical logic gates, we will use the figure-of-merit of the logic gates (FOMELG (dB)) defined as a function of the extinction ratio of the gate outputs. All results were obtained numerically, considering a very simple model for generation of a optical logic gates.

Proses Pengiriman Paket IP Menggunakan All Optical Label Swapping (AOLS)

Transmission IP packet into WDM network will experience of encapsulation process at Data Link Layer with adding overhead to packet. IP packet through Gigabit Ethernet have more less overhead than ATM. The usage of All Optical Label Swapping (AOLS) technology for transmitting IP packet into WDM network with using label swapping will add optical label to packet. At AOLS, process routing decision is to be done with only processing the optic label. During that process data payload constantly within optic domain. Key word : ATM, Gigabit Ethernet, AOLS, optic label.

All-optical Label Swapping Techniques for Optical Packets at Bit-rate Beyond 160 Gb/s

In this paper t wo different paradigms to realize a scalable all-optical packet switch with label swapping will be presented. All the functions required for switching the packets are based on all-optical signal processing without any electronic control. This allows very low latency and potential photonic integration of the systems. We report for both techniques experimental results showing the routing operation of the 160 Gb/s packets and beyond. W e will discuss and compare both techniques in term of devices and bit-rate scalability, latency, power consumption, power penalty performance and cascadability as key parameters for the realization of an all-optical packet switch.

Experimental demonstration and analysis of all-optical label swapping based on RZ-DQPSK/IRZ-ASK modulation format

A novel optical return zero differential quadrature phase shifted keying/inverse return zero amplitude shifted keying (RZ-DQPSK/IRZ-ASK) orthogonal modulation format scheme for all-optical label swapping is analyzed theoretically and experimentally. The transmission characteristics of RZ-DQPSK/IRZ-ASK modulation format transmission system are demonstrated. Results show that high extinction ratio is obtained for IRZ-ASK label signal while at the same time the all-optical label swapping, differential quadrature phase shifted keying (DQPSK) payload signal is hardly affected. It requires only 0.9 dB higher power penalty compared to 21.4 Gbit/s RZ-DQPSK modulation format and less than 2 dB transmission penalty after 60 km. The proposed scheme is a practical solution for meeting the data rate and cost-efficiency of the optical links simultaneously in future all-optical label swapping.

Simultaneous erasure and rewriting of a subcarrier-multiplexed label in an all-optical label swapping scheme

A simplified all-optical label swapping scheme is proposed and experimentally demonstrated for all-optical packet switching. This scheme is based on the sub-carrier label multiplexing technique but it significantly reduces the cost and complexity of the label erasure and rewriting process at the intermediate nodes. This is accomplished using a shared interferometric filter for all wavelength channels to separate the payloads and labels as well as using gain-saturated RSOAs for label erasure and rewriting. Label swapping process is realized through re-assigning optical subcarriers to each output wavelength channel and rewriting the new label with RSOAs. The BER-free transmissions experimentally demonstrate the feasibility of the proposed scheme.

A novel all-optical label swapping based on RZ-DQPSK/IRZ-ASK combined modulation format

A novel all-optical label swapping based on optical return zero (RZ) differential quadrature phase shifted keying/inverse return zero amplitude shifted keying (RZ-DQPSK/IRZ-ASK) combined modulation format scheme is investigated and analyzed theoretically. Internet protocol (IP) packets can be efficiently labeled and processed using this proposed scheme. Numerical simulation is taken to demonstrate the transmission characteristic of the all-optical label swapping based on RZ-DQPSK/IRZ-ASK modulation format. The transmission performance can be affected by the duty cycle of the IRZ pulse, the IRZ-ASK label extinction ratio, the dispersion compensation ratio, received optical power and the coupling coefficient of the coupler. Results show that the IRZ-ASK label extinction ratio is almost infinite and preferable performance is obtained. The proposed scheme is a practical solution to meet the data rate and cost-efficient of the optical links simultaneously in tomorrow's all-optical label swapping.

All-Optical Label Swapping Using Bistable Semiconductor Ring Laser in an Optical Switching Node

This paper demonstrates an optical node that simultaneously carries out multicast optical switching and all-optical label swapping. While the optical payload is being forwarded by a fast optical switch matrix, the optical label is processed by a semiconductor ring laser (SRL) bistable. Old address bits in the label are erased by optically blocking the switching of the ring laser and new address bits are inserted by modulating the output from SRL directly. This label swapping scheme is the first demonstration of bit-level data processing using the all-optical logic capabilities of a semiconductor ring laser.

All-Optical Label Swapping of Scalable In-Band Address Labels and 160-Gb/s Data Packets

Scalability and photonic integration of packet switched cross-connect nodes that utilize all-optical signal processing is a crucial issue that eventually determines the future role of photonic signal processing in optical networks. We present a 1times4 all-optical packet switch based on label swapping technique that utilizes a scalable and asynchronous label processor and label rewriter. By combining N in-band labels at different wavelengths (within the bandwidth of the payload), up to 2N possible addresses can be encoded. The proposed label processor requires only N active devices to process the 2N addresses that makes this label processing technique scalable with the number of addresses. Experimental results showed error-free packet switching operation at 160 Gb/s. The label erasing and new label insertion operation introduces only 0.5 dB of power penalty. These results indicate a potential utilization of the presented technique in a multi-hop packet switched network.

All-optical label swapping of in-band addresses and 160 Gbit/s data packets

A 1×4 all-optical packet switch is presented, based on an optical label swapping technique that utilises a scalable label processor and a label rewriter with ‘on the fly’ operation. Experimental results show error-free packet switching with a data payload at 160 Gbit/s. The label erasing and new label insertion operation introduces 0.5 dB of power penalty. These results indicate a potential utilisation of the presented technique in a multi-hop packet switched network.

Scalable architectures for all-optical label swapping nodes

All-Optical Label Swapping (AOLS) nodes are believed to be part of the future networks. The original node designs, however, are very hard scalable. This article presents three alternatives that swap labels analogous to the original design. Two of the proposed new switches use the same all-optical technology to parallelly compare labels but, they divide fibres in data wavelengths that only transport payloads and label wavelengths that only transport labels. The third design sequentially compares the incoming label with addresses in the node available in order to make the routing decision. All three architectures are compared in terms of hardware necessary to perform routing.

All-Optical Processing Based on a Logic xor Gate and a Flip-Flop Memory for Packet-Switched Networks

The routing functionality by all-optically interconnecting semiconductor-based all-optical logic gates and flip-flops is demonstrated in the frame of an all-optical label swapping (AOLS) network. We experimentally show that the output of the all-optical 2-bit correlator is capable of toggling the states of the integrated flip-flop every 2.5 ns via an adaptation stage. High extinction ratios are obtained at the output of the flip-flop, which can be used to feed a high-speed wavelength converter to complete the routing functionality of the AOLS node. The potential integration of these semiconductor optical amplifier integrated Mach-Zehnder interferometer-based devices make the proposed approach a very interesting solution for future packet switched optical networks.

All-Optical Label Swapping, Clock Recovery, and 3R Regeneration in 101-Hop Cascaded Optical-Label Switching Router Networks

This paper experimentally demonstrates the cascaded operation of an optical-label switching router for up to 101 hops, with optical label swapping, optical clock recovery, and 3R regeneration (re-amplification, reshaping, and retiming) at each hop. The optical label swapping utilizes all-optical payload/label separation and label rewriting with subcarrier label. An interferometer wavelength converter enables the reshaping function, while the synchronous modulation driven by the optically recovered packet clock performs the retiming function. The optical label swapping and 3R regeneration enable the packets to traverse a large number of hops while maintaining the signal quality to support the scalability of the optical-label switching network

Benefits of label stripping compared to label swapping from the point of node dimensioning

All-Optical Label Swapping (AOLS) is a promising packet-switching technology to accomplish the gap between router forwarding speed and fibre transmission speed. The hardware requirements from the node however are unarguable a big disadvantage of these kinds of nodes. In this paper, we present two all-optical label switching nodes. One is based on the MPLS technology and one is an alternative switching strategy for packet-switching: label stripping. We compare both node architectures in terms of hardware requirements for different switching strategies and network parameters (such as topology and number of nodes).

On polarization sensitivity of all-optical label swapping using synchronous phase modulation

Polarization sensitivity degrades the performance of many optical devices in optical packet switched networks. We investigate the polarization sensitivity for all-optical label swapping for the first time. We propose and demonstrate a polarization-insensitive phase modulator for all-optical label swapping. The polarization sensitivity of the power penalty for the label swapping is less than 0.3 dB

A compact all-optical subcarrier label-swapping system using an integrated EML for 10-Gb/s optical label-switching networks

We propose a compact and simple all-optical subcarrier-multiplexed (SCM) label-swapping system employing an integrated electroabsorption modulation laser and a semiconductor optical amplifier based Mach-Zehnder interferometer wavelength converter. The experiments demonstrated error-free all-optical label swapping for the 155-Mb/s label and 10-Gb/s payload over two optical label-switching network nodes with less than 0.7-dB power penalty on the payload. The majority of the components in this SCM label-swapping system can be realized on a semiconductor platform (e.g., InP), which implies a step toward possible monolithic or hybrid integration of the all-optical label-swapping system in the future.

Experimental investigation of transmission properties and label swapping of an orthogonal ASK/FSK labeled signal

This paper presents an experimental assessment of the transmission performance and all-optical label swapping for an orthogonal amplitude-shift keying-frequency-shift keying (ASK-FSK) labeled signal. Transmission through different dispersion maps with various compensation schemes and fiber types is investigated. All-optical label erasure, reinsertion, and multihop transmission are experimentally demonstrated.

Intensity-modulated labeling and all-optical label swapping on angle-modulated optical packets

We proposed and investigated superimposing intensity-modulated labels onto high-speed angle-modulated payloads in optical label-switching packet networks. This can largely simplify the all-optical label swapping, including label extraction, processing, removal, and new label insertion. The transmission performances of 1.244-Gb/s on-off keying labels on 9.953-Gb/s optical frequency-shift keying and differential phase-shift keying payloads were investigated; and the all-optical label swapping was successfully demonstrated with low penalty.

All-Optical ASK/DPSK Label-Swapping and Buffering Using Fabry–Perot Laser Diodes

We describe an approach for optical label encoding that allows the realization of all-optical label-swapping in optical packet-switched networks. The proposed method is based on a combination of the amplitude-shift-keying (ASK) modulated payload with the differential phase-shift keying (DPSK) modulated label on the same optical carrier. We demonstrate an implementation using dual-wavelength injection locking (DWIL) of a Fabry-Perot laser diode. Bit-error-rate measurements were performed for the 10-Gb/s payload, and the 2.5-Gb/s label showed the feasibility of the proposed method. An all-optical buffer for the two-level ASK/DPSK optically labeled packets is also described. The buffer is implemented by routing the packet via a delay line if potential contention is predicted. Error-free operation was also achieved.