Quantum key distribution and 1 Gbit/s data encryption over a single fibre

We perform quantum key distribution (QKD) in the presence of 4 classical channels in a C-band dense wavelength division multiplexing (DWDM) configuration using a commercial QKD system. The classical channels are used for key distillation and 1 Gbps encrypted communication, rendering the entire system independent from any other communication channel than a single dedicated fibre. We successfully distil secret keys over fibre spans of up to 50 km. The separation between quantum channel and nearest classical channel is only 200 GHz, while the classical channels are all separated by 100 GHz. In addition to that we discuss possible improvements and alternative configurations, for instance whether it is advantageous to choose the quantum channel at 1310 nm or to opt for a pure C-band configuration.Comment: 9 pages, 7 figure

New generation of devices for all-optical communications

To increase the transmission capacity of future communication networks is becoming very critical. This task can only be accomplished by taking advantage of optical networks where multiplexing techniques such as Dense Wavelength Division Multiplexing (DWDM) and Optical Time Division Multiplexing (OTDM) are employed. To avoid electronic bottlenecks a whole new generation of ultrafast devices is needed. To fulfil these needs a new class of all optical devices has been proposed and developed. By taking advantage of the nonlinear dynamics in semiconductor optical amplifiers in combination with the fiber interferometers a new generation of ultrafast all-optical demultiplexers and wavelength converters has been demonstrated. Other switching technologies are also promising for the future. The latest technologies in the area of micro-machining have created very attractive low cost MEMS. Recently announced use of bubble technology for all-optical switching might also lead to the development of next generation large scale switching fabrics. This paper is an overview of the recent development in these areas

TDM 100 Gb/s packet switching in an optical shuffle network

The feasibility of achieving large throughput in a single wavelength channel using TDM is discussed. The system is implemented with electronic routing control having networks that are often referred as transparent optical networks. The processing time required by the electronic routing controllers depends on the complexity of the routing algorithm employed, so it is critical to develop simple and efficient routing schemes. The system demonstrated packet switching in an 8-node shuffle networks using a physical node by connecting the two output links back to one of the input links using 500 m of fiber. The routing controller traces the path of a test packet by reconfiguring the node identified after performing switching on the test packet

New trends in optical communications

To increase the transmission capacity of future communication networks is becoming very critical. This task can only be accomplished by taking advantage of optical networks where multiplexing techniques such as Dense Wavelength Division Multiplexing (DWDM) and Optical Time Division Multiplexing (OTDM) are employed. To avoid electronic bottlenecks a whole new generation of ultrafast devices is needed. To fulfill these needs a new class of all optical devices has been proposed and developed. By taking advantage of the nonlinear dynamics the semiconductor optical amplifiers in combination with the fiber interferometers a new generation of ultrafast all-optical demultiplexers and wavelength converters has been demonstrated. Newly developed broadband optical fiber, a new generation of fiber amplifiers, and extensive progress in dispersion management has helped substantially to increase bitrates and transmission distances (bandwidth-distance product) in the current optical networks. The latest technologies in the area of micro-machining have created very attractive low cost MEMS. Recently announced use of bubble technology for all-optical switching might also lead to the development of next generation large scale switching fabrics. In this paper we discuss progress and new trends in some of these areas

Comparison of three nonlinear optical switch geometries

Three optical switch geometries have been compared and investigated. These are the Terahertz Optical Asymmetric Demultiplexer (TOAD), Colliding Pulse Mach-Zehnder (CPMZ), and Symmetric Mach-Zehnder (SMZ). Of the three geometries, the SMZ switch exhibits the best performance in terms of the minimum switching window width and output peak-to-peak amplitude. The control pulse energy requirements of all three devices are at least an order of magnitude less than the energy required by passive structures

Demonstration of multicasting capability in a 100-Gb/s OTDM switched interconnect

A 100 Gb/s optical time division multiplexing interconnect based on a broadcast star architecture logically equivalent to a fully connected crossbar but uses only N switching elements is described. This single-hop, broadcast-and-select architecture offers single cycle channel access latency by employing a fast time slot tuner only in the transmitter of each node. As a router, it scales gracefully and offers 1 Tb/s aggregate bandwidth and support over 1000 nodes. The capability of the interconnect is extended to provide full multicasting functionality to a rich subset of network nodes

Comparison of three nonlinear interferometric optical switch geometries

We present an experimental study of ultrafast all-optical interferometric switching devices based upon a resonant nonlinearity in a semiconductor optical amplifier (SOA). We experimentally compare three configurations: one based upon a Sagnac interferometer and the other two based upon Mach-Zehnder interferometers. By using picosecond pulses, we characterize the switching window of the three devices in terms of both temporal width and output peak-to-peak amplitude. These results are found to be in close agreement with a previously developed theoretical model. Since these nonlinear interferometric switches use an active device as the nonlinear element, relatively low control pulse energy is needed to perform switching as compared to other techniques. As a result, these optical switches are practical for all-optical demultiplexing and ultrafast optical sampling for future lightwave communication systems

Analysis of a rapidly reconfigurable multicast capable photonic switched interconnect

We present a complete mathematical formalism for a rapidly reconfigurable gated timeslot tuner based on a serial feed-forward structure. This gated serial timeslot tuner has been a key component for various demonstrations including a 100 Gb/s photonic switched interconnect [K.-L. Deng, R.J. Runser, P. Toliver, I. Glesk, P.R. Prucnal, J. Lightwave Technol. 18 (2000) 1892]. Design constraints for the proper operation of the interconnect are developed. Methods to predict feasible multicast combinations and control patterns required for driving the timeslot tuner are presented in terms of a two-dimensional (2D) contour map

Practical all-optical sampling technique for high bandwidth, low energy optical communication signals

An extremely simple, real-time measurement technique for characterizing high-speed, low energy optical communication signals using an ultrafast SOA-based optical switch and low bandwidth electronics is presented. The technique successfully resolves pulses with an energy of 1.5 fJ in a 160 GHz pulse stream using a 10-GHz repetition rate optical control with pulse energy of only 20 fJ

Demonstration of multicasting in a 100-Gb/s OTDM switched interconnect

We show that a 100-Gb/s OTDM interconnect can provide full multicasting capability using a simplified node architecture. In our demonstration, subsets of 16 channels are accessed simultaneously from a multicasting node with a setup time of 3.2 ns. This additional functionality allows the interconnect to support multicasting as well as advanced services such as single-cycle multi-channel arbitration and speed-up N mode