Alan Naughton

A 135-km 8192-Split Carrier Distributed DWDM-TDMA PON With 2

We present a hybrid dense wavelength-division-multiplexed time-division multiple access passive optical network (DWDM-TDMA PON) with record performance in terms of reach (135.1 km of which 124 km were field-installed fibers), number of supported optical network units (ONUs-8192) and capacity (symmetric 320 Gb/s). This was done using 32-, 50-GHz-spaced downstream wavelengths and another 32-, 50-GHz-spaced upstream wavelengths, each carrying 10 Gb/s traffic (256 ONUs per wavelength, upstream operated in burst mode). The 10 Gb/s downstream channels were based upon DFB lasers (arranged in a DWDM grid), whose outputs were modulated using a electro-absorption modulator (EAM). The downstream channels were terminated using avalanche photodiodes in the optical networks units (ONUs). Erbium-doped fiber amplifiers (EDFAs) provided the gain to overcome the large fiber and splitting losses. The 10 Gb/s upstream channels were based upon seed carriers (arranged in a DWDM grid) distributed from the service node towards the optical network units (ONUs) located in the users premises. The ONUs boosted, modulated, and reflected these seed carriers back toward the service node using integrated 10 Gb/s reflective EAM-SOAs (EAM-semiconductor optical amplifier). This seed carrier distribution scheme offers the advantage that all wavelength referencing is done in the well-controlled environment of the service node. The bursty upstream channels were further supported by gain stabilized EDFAs and a 3R 10 Gb/s burst-mode receiver with electronic dispersion compensation. The demonstrated network concept allows integration of metro and optical access networks into a single all-optical system, which has potential for capital and operational expenditure savings for operators.

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We report on a hybrid DWDM-TDM A optical access network that provides a route for integrating access and metro net- works into a single all-optical system. The greatest challenge in using DWDM in optical access networks is to precisely align the wavelength of the customer transmitter (Tx) with a DWDM wave- length grid at low cost. Here, this was achieved using novel tunable, external cavity lasers in the optical network units (ONUs) at the customers end. To further support the upstream link, a 10 Gb/s burst mode receiver (BMRx) was developed and gain-stabilized erbium-doped fiber amplifiers (EDFAs) were used in the network experiments. The experimental results show that 10 Gb/s bit rates can be achieved both in the downstream and upstream (operated in burst mode) direction over a reach of 100 km. Up to 32 × 50 GHz spaced downstream wavelengths and another 32 × 50 GHz spaced upstream wavelengths can be supported. A 512 split per wave- length was achieved: the network is then capable of distributing a symmetric 320 Gb/s capacity to 16384 customers. The proposed architecture is a potential candidate for future optical access net- works. Indeed it spreads the cost of the network equipment over a very large customer base, allows for node consolidation and integration of metro and optical access networks into an all-optical system.

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A DWDM-TDMA PON using carrier distribution with symmetric 320 Gb/s capacity is demonstrated over 124 km field-installed fibers. The upstream channels feature a 3R 10 Gb/s burst-mode receiver with electronic dispersion compensation, burst-mode EDFAs and integrated reflective SOA-EAMs.

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We present hybrid DWDM-TDMA PONs as a means for integration of access and metro networks, and review results from recent system demonstrations. Results on a novel burst-mode receiver specifically designed for such systems are provided.

10 Gb/s Capacity

We show that loss-optimised, gain-saturated SOA-REAM-based reflective modulators have the potential to reduce upstream channel dynamic range by 18dB compared to fixed linear-gain modulators in a carrier-distributed-PON application. This is achieved with minimal patterning penalties.

Demonstration of a 32

We demonstrate a DWDM-TDMA PON with symmetric 320 Gb/s capacity shared between 16384 customers. The upstream channels were tested in burst-mode and feature low-cost tuneable lasers, monolithically integrated SOA-EAMs, burst-mode EDFAs and a 10 Gb/s burst-mode receiver.

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Reflective modulators based on an electro-absorption modulator (EAM) and semiconductor optical amplifier (SOA) combination are attractive devices for applications in carrier distributed optical access networks due to the gain, provided by the SOA, and the high speed and low chirp modulation of the EAM. Monolithically integrated reflective EAM-SOAs (R-EAM-SOAs) have demonstrated unexpected and unintuitive behavior, which is related to the gain saturation properties of the SOA section and also to the internal loss present after the SOA section. Results from a simple analytical model and from an accurate numerical model show that a high value of internal loss and a high gain SOA allow utilization of these devices in a region where the output power is clamped around a maximum value for input carrier powers compatible with carrier distributed optical access networks. In this region of operation the R-EAM-SOA also exhibits low patterning distortion, despite being in a saturated regime, and noise reduction on the input carrier due to the noise squeezing in the SOA section. In this paper, we demonstrate that these three effects, which are highly desirable in carrier distributed optical access networks, can be readily achieved via a co-optimization of the SOA section parameters and the internal loss values in integrated R-EAM-SOAs.

512 Split, 100 km Reach, 2

We report on a hybrid reflective electroabsorption modulator-based photonic integrated circuit, demonstrating error-free 25.3Gb/s duobinary transmission (BER<;1×10-12) over 35km of SSMF. Colourless operation with 1.2dB OSNR variation over the C-band is confirmed.

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We demonstrate a novel hybrid photonic integrated circuit, incorporating reflective electroabsorption modulators, which achieves error-free 10Gb/s duobinary transmission over 215km of standard fiber with similar performance to a commercial lithium niobate duobinary MZM.

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Exponentially-increasing demands on the current telecommunication infrastructure are driving the development of next-generation ultra-high-bandwidth network architectures with sufficiently low energy consumptions. Within the scope of the EU FP7 C3PO project, we are developing novel, energy-efficient, colourless photonic technologies for metro applications. The colourless transmitters will leverage reflective photonic integrated circuits, specifically reflective electroabsorption modulator-based phase and amplitude modulators, in conjunction with multi-frequency lasers and low-loss piezoelectric beam-steering optical matrix switches, in order to achieve wavelength reconfigurability without the requirement for tuneable lasers. A specific target is a dynamically reconfigurable metro node which supports duobinary modulation for high dispersion tolerance and efficient spectral usage, to enable 100 Gb/s Ethernet dense wavelength-division-multiplexed transport networks. We report on recent progress towards these metro transport networks, providing the latest system test results obtained using novel hybrid photonic integrated devices.