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A novel methodology for analyzing the advantageous decoding performance of multibranch configurations of low-bit optical soft-decision forward error correction receivers is presented. The decoding performance and noise behavior of three front-end schemes are evaluated and compared. Arising from a multiple-branch configuration, the concept of inconsistency in the decoder (thermometer code) is presented and used to optimize decoding performance. The experimentally validated methodology considers both optically amplified long-haul and short-reach applications. [ABSTRACT FROM PUBLISHER]

This paper presents an energy-efficient multi-plane optical interconnection network to interconnect servers in a data center. The novel architecture uses the time domain to individually address each port within a card and the space domain to address each card. Optical enabling technologies passively time-compress serial packets by exploiting the wavelength domain and perform a broadcast-and-select to a destination card with minimum power dissipation. Scalability of both the physical layer and the overall power dissipation of the architecture is shown to be enhanced with respect to the existing interconnection network architectures based on space and wavelength domains. The space–time network architecture is scalable up to 216 ports with space-switches exhibiting energy efficiency of the order of picojoules per bit, thanks to the self-enabled semiconductor-optical-amplifier-based space-switches. [ABSTRACT FROM PUBLISHER]

A complete review of the data vortex optical packet switched (OPS) interconnection network architecture is presented. The distributed multistage network topology is based on a banyan structure and incorporates a deflection routing scheme ideally suited for implementation with optical components. An implemented 12-port system prototype employs broadband semiconductor optical amplifier switching nodes and is capable of successfully routing multichannel wavelength-division multiplexing packets while maintaining practically error-free signal integrity (BER < 10-12) with median latencies of 110 ns. Packet contentions are resolved without the use of optical buffers via a distributed deflection routing control scheme. The entire payload path in the optical domain exhibits a capacity of nearly 1 Tb/s. Further experimental measurements investigate the OPS interconnection network's flexibility and robustness in terms of optical power dynamic range and network timing. Subsequent experimental investigations support the physical layer scalability of the implemented architecture and serve to substantiate the merits of the data vortex OPS network architectural paradigm. Finally, modified design considerations that aim to increase the network throughput and device-level performance are presented. [ABSTRACT FROM PUBLISHER]

The small polarization dependence (< 1 dB) of optical components becomes significant in optical multistage interconnection networks. The cumulative effect can ultimately limit physical layer scalability by changing the maximum number of internal nodes that optical packets can traverse error free. It is shown that for nodes based on commercial semiconductor optical amplifier (SOA) switches with polarization-dependent gains of less than 0.35 dB, the maximum number of cascaded nodes changes by as much as 20 nodes, depending on both the packet wavelength and its state of polarization. This deviation in the number of nodes could correspond to a 100-fold decrease in the number of interconnected ports of an optical interconnection network such as the data vortex. This dramatic effect is explained in terms of optical signal-to-noise ratio degradation due to accumulated amplified spontaneous emission noise originating from the SOA device in the node [ABSTRACT FROM PUBLISHER]

The physical layer scalability of a packet-switched optical interconnection network utilizing semiconductor optical amplifier (SOA) switch elements is investigated experimentally and with numerical modeling. Optical packets containing payloads of multiple wavelength-division-multiplexing (WDM) channels are propagated through cascaded SOA-based switching nodes in a recirculating test-bed environment. Experiments show that bit-error rates (BERs) below 10-9 can be maintained through 58 switching nodes for the entire eight-channel 10-Gb/s-per-channel payload distributed over 24.2 nm of the C-band. When the packet payload consists of a single 10-Gb/s channel, 98 node hops can be traversed before a BER of 10-9 is exceeded. In conjunction with the experiments, a novel phenomenological modeling technique is developed in order to forecast the scalability of SOA-based WDM packet interconnection networks. This technique is shown to yield results that correlate well with the experimental data. These investigations are presented as predictors of the physical limitations of large-scale WDM packet-switched networks. [ABSTRACT FROM PUBLISHER]

A fully functional optical packet switching (OPS) interconnection network based on the data vortex architecture is presented. The photonic switching fabric uniquely capitalizes on the enormous bandwidth advantage of wavelength division multiplexing (WDM) wavelength parallelism while delivering minimal packet transit latency. Utilizing semiconductor optical amplifier (SOA)-based switching nodes and conventional fiber-optic technology, the 12-port system exhibits a capacity of nearly 1 Tb/s. Optical packets containing an eight-wavelength WDM payload with 10 Gb/s per wavelength are routed successfully to all 12 ports while maintaining a bit error rate (BER) of 10-12 or better. Median port-to-port latencies of 110 ns are achieved with a distributed deflection routing network that resolves packet contention on-the-fly without the use of optical buffers and maintains the entire payload path in the optical domain. [ABSTRACT FROM PUBLISHER]

In this letter, the performance of an ultra-wideband (UWB)-over-fiber system with low-density parity-check (LDPC) coding is experimentally investigated and supported by a simulation study. The results show that short block length LDPC coding provides a coding gain between 5.75 and 8.5 dB for a code rate of 50% and 93.3%, respectively, compared to an uncoded UWB-over-fiber system at a bit-error rate of 10^-8 after error correction. [ABSTRACT FROM PUBLISHER]

In this letter, we demonstrate a 2 times 2 switching node optimized for optical multistage interconnection networks. The optical packet-switched node is improved by making use of comparators with dual-threshold action to regenerate the routing header signal. The switching node is shown to correctly route packets with the presence of glitches in the header information. We employ a hybrid integrated semiconductor optical amplifier in the switching node that reduces packet guard times enabling a 67% increase in the number of stages for large-scale multistage networks. [ABSTRACT FROM PUBLISHER]

The physical layer scalability of multistage interconnection networks is determined by the maximum number of internal switching nodes that packets can traverse error-free. We show that for nodes based on commercial semiconductor optical amplifier switches with polarization-dependent gain of less than 0.35 dB, the maximum number of cascaded nodes could vary by as much as 20 nodes, depending both on the packet wavelength and its state of polarization. We explain such a dramatic effect by optical signal-to-noise ratio degradation due to accumulated amplified spontaneous emission noise with the number of nodes. [ABSTRACT FROM PUBLISHER]