Optical-Connections-Q1-2016-OFC-Edition-LR2 (1)

matthew peach

demonstrates

sophisticated and complete testing solutions, which need to offer generation and analysis functions for both the transmitter and receiver side of the network technologies under investigation. development companies can support efforts to enable their customers to rely on the best solution for each portion of the test system they are going to select. ECOC demonstration Anritsu, Coherent Solutions, Oclaro and Teledyne LeCroy partnered at ECOC 2015 in Valencia, Spain, to implement the industry’s first commercially available research and development platform for testing single- carrier coherent optical communication systems and components operating at 56GBaud and above. This platform was showcased in a demonstration based on test and measurement (T&M) tools, showing complete 56G DP-QPSK (Dual Polarisation, Quadrature Phase Shift Keying) transmitter and receiver simulation and analysis. This technique is also known as PM-QPSK. Among the many different implementations of coherent transmission, which are under investigation, DP-QPSK is so far the most commonly- adopted and shows the best price/performance trade off for long distance reach. Simulating and analysing results for such implementation requires a T&M rig to be able to perform the following: 1. Generate best quality, four parallel, high speed, digital electrical signals, relying on a reference transmitted integrity on each channel; For this reason, test and measurement systems

The industries first commercially available R&D platform for testing single-carrier coherent systems at 56GBaud and above

channels synchronisation, signal integrity, linearity, intrinsic jitter and cleanness, phase noise, EVM, BER, and modulation signal to noise ratio. Anritsu and the three partner companies were able to implement a system solution that allows complete simulation and analysis for both the transmitter and the receiver side of a complex 200Gbps DP-QPSK modulation implementation. The foreseeable next step is to focus on achieving the first T&M solution for 400GBbps simulation and analysis, by including the additional 4-PAM (Pulse Amplitude Modulation on four levels) coding of the original 50Gbps electrical signals and implementing a 16-QAM (Quadrature Amplitude Modulation) system. New development The technical solution described above coincided with Anritsu recently announcing a new evolution for the MP1800A Signal Quality Analyser platform, with the addition of the new MP1861A 64.2Gbps Mux, MP1862A 64,2Gbps Demux, MZ1854A PAM4 Combiner. This combined solution covers signal generation, analysis and jitter tolerance testing up to 64.2Gbps, as a worldwide solution for R&D on signal transmission up to 1Tbps.

• Oclaro providing the internal single carrier 400G LiNbO3 optical modulator inside Coherent’s transmitter, and supporting with tuning and trialling know-how; • Teledyne LeCroy completing the setup with its 65GHz bandwidth LabMaster 10-65Zi-A OMA system incorporating the new IQS70 70GHz Coherent Optical Receiver and OpticalLinQ software for Constellation Analysis The four electrical 50Gbps signals, equivalent to a simulated 200Gbps data content to be transmitted on a network link, were phase modulated in quadrature and transmitted on a single, dual polarisation, optical carrier. By this means, the optical carrier runs on a fibre with a nominal speed of 50GBaud but actually transports 200Gbps data content. On the receiver side, through the coherent optical receiver’s demodulator, the original four 50Gbps channels are rebuilt and sent to the real time scope, where they are analysed to verify the quality of the transmission link. Key parameters to be evaluated with such test and measurement solution, to enable research labs to progress in releasing higher performance techniques, are

2. Utilise a high speed, high quality optical modulator, to move from multiple reference electrical signals to a single reference modulated optical signal; 3. Integrate a suitable coherent receiver, which can align to the received signal modulation and convert the signal back to the unmodulated sequences; 4. Adopt a large bandwidth and high quality real time oscilloscope, with constellation analysis capability, to verify phase noise and the error vector magnitude of each parallel data channel; The demonstration partners combined their technologies in the following way: • Anritsu offering two differential channels from the MP1800 Signal Quality Analyser with two MP1861A 64G MUXes, to generate four high quality parallel electrical single-ended 50Gbps signals; • Coherent Solutions adding its 40GHz bandwidth IQTransmitter, with the new modulator Automatic Bias Control circuitry, which provides fully pattern- independent bias control, to modulate the signals; 50Gbps pure Pseudo Random Bit Sequence

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