P. Gunning

Symbol Synchronization Exploiting the Symmetric Property in Optical Fast OFDM

We propose a new simple method to achieve precise symbol synchronization using one start-of-frame (SOF) symbol in optical fast orthogonal frequency-division multiplexing (FOFDM) with subchannel spacing equal to half of the symbol rate per subcarrier. The proposed method first identifies the SOF symbol, then exploits the evenly symmetric property of the discrete cosine transform in FOFDM, which is also valid in the presence of chromatic dispersion, to achieve precise symbol synchronization. We demonstrate its use in a 16.88-Gb/s phase-shifted-keying-based FOFDM system over a 124-km field-installed single-mode fiber link and show that this technique operates well in automatic precise symbol synchronization at an optical signal-to-noise ratio as low as 3 dB and after transmission.

First field demonstration of cloud datacenter workflow automation employing dynamic optical transport network resources under OpenStack and OpenFlow orchestration

For the first time, we demonstrate the orchestration of elastic datacenter and inter-datacenter transport network resources using a combination of OpenStack and OpenFlow. Programmatic control allows a datacenter operator to dynamically request optical lightpaths from a transport network operator to accommodate rapid changes of inter-datacenter workflows.

Unrepeatered field transmission of 2 Tbit/s multi-banded coherent WDM over 124 km of installed SMF

In this paper we report field transmission of a 2 Tbit/s multi-banded Coherent WDM signal over BT Irelands installed SMF, using EDFA amplification only, with mixed Ethernet (with FEC) and PRBS payloads. To the best of our knowledge, the results obtained represent the highest total capacity transmitted over installed SMF with orthogonal subcarriers. BERs below 10(-5) and no frame-loss were recorded for all 49 subcarriers. Extended BER measurements over several hours showed fluctuations that can be attributed to PMD and to dynamic effects associated with clock instabilities.

10 Gbit/s asynchronous digital optical regenerator

We describe the first experimental demonstration of an asynchronous digital optical regenerator. Error-free regeneration of 10-Gb/s optical packets up to 40000 bits long has been demonstrated without clock recovery. It is demonstrated that the optical nodes in this network may operate with independent clocks, within certain practical limits, offering the possibility of arbitrary mesh optical time-division multiplexing networks.

A novel field-detection maximum-likelihood sequence estimation for chromatic-dispersion compensation

We propose a novel field-detection based maximum likelihood sequence estimation (FD-MLSE), and experimentally demonstrate transmission over 372 km of field-installed SMF without optical dispersion compensation using a 4-state MLSE.

A novel method for precise symbol synchronization in double-side band optical fast OFDM

We propose a novel method to achieve precise symbol synchronization using one training symbol in DSB optical fast OFDM (FOFDM). World-first FOFDM transmission experiment using field-installed fiber verifies its robustness to the noise and CD.

Impact of Raman Amplification on a 2-Tb/s Coherent WDM System

The impact of hybrid erbium-doped fiber amplifier (EDFA)/Raman amplification on a spectrally efficient coherent-wavelength-division-multiplexed (CoWDM) optical communication system is experimentally studied and modeled. Simulations suggested that 23-dB Raman gain over an unrepeatered span of 124 km single-mode fiber would allow a decrease of the mean input power of ~6 dB for a fixed bit-error rate (BER). Experimentally we demonstrated 1.2-dB Q-factor improvement for a 2-Tb/s seven-band CoWDM with backward Raman amplification. The system delivered an optical signal-to-noise ratio of 35 dB at the output of the receiver preamplifier providing a worst-case BER of 2 × 10 -6 over 49 subcarriers at 42.8 Gbaud, leaving a system margin (in terms of Q -factor) of ~4 dB from the forward-error correction threshold.

Dispersion Tolerance Enhancement in Electronic Dispersion Compensation using Full Optical-Field Reconstruction

We experimentally verify the feasibility of receiver-side electronic dispersion compensation using optical-field reconstruction, and theoretically increase the fundamental limit of this technique to 2000 km by successfully suppressing the instability from low-frequency amplification in phase reconstruction.

100 Gbit/s parallel to-serial and serial to-parallel conversion using electroabsorption modulators

We show that electroabsorption modulators (EAMs) can be used as the basis of serial-to-parallel and parallel-to-serial convertors, the latter by demonstrating the use of an EAM to extract a 10 Gbit/s channel from a 100 Gbit/s serial bit-stream. We envisage that a further stage of serialisation or parallelisation would be carried out in the electrical domain at the transmitter and receiver respectively to fit in with the requirements of the backplane.

Prospects for software defined networking and network function virtualization in media and broadcast

Software Defined Networking (SDN) and Network Function Virtualization (NFV) provide an alluring vision of how to transform broadcast, contribution and content distribution networks. In our laboratory we assembled a multi-vendor, multi-layer media network environment that used SDN controllers and NFV-based applications to schedule, coordinate, and control media flows across broadcast and contribution network infrastructure. — This paper will share our experiences of investigating, designing and experimenting in order to build the next generation broadcast and contribution network. We will describe our experience of dynamic workflow automation of high-bandwidth broadcast and media services across multi-layered optical network environment using SDN-based technologies for programmatic forwarding plane control and orchestration of key network functions hosted on virtual machines. Finally, we will outline the prospects for the future of how packet and optical technologies might continue to scale to support the transport of increasingly growing broadcast media.