C. Ford

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.

\,\times\,

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.

32

We have given the first quantitative description of the amplitude squeezing effect in semiconductor optical amplifiers/modulators and shown how this effect can be exploited in a spectrally-sliced WDM-PON. A system demonstration of 8 Gigabit Ethernet channels over 25 km of standard access fibre was presented.

\,\times\,

Passive assembly of single mode optoelectronic components is a prerequisite for some of the more advanced functional devices emerging in the marketplace. For example, in optical processing circuits (Cotter, 1995) it is essential to have serially cascaded active devices with time of flight control of the optical data. In such cases, the functionality cannot be achieved through any means other than hybrid integration of monolithic active chips with passive planar waveguides. This paper describes a high performance integration platform that can scale to high levels of monolithic chip integration on a hybrid waveguide motherboard which is suitable for these applications.

10 Gb/s Capacity

We present a 10 Gb/s burst-mode receiver featuring automatic reset generation. The measured sensitivity is -12.5 dBm at a loud/soft ratio of 11.5 dB with a guard time of 25.6 ns and a short preamble of 23.8 ns.

Demonstration of a 32

Todays broadband access is moving towards PONs at 10Gb/s. This requires a burst-mode receiver to support the TDMA protocol used in its upstream path. Such a receiver consists of a burst-mode transimpedance amplifier (BM-TIA) which largely dictates the performance of the receiver and a burst-mode post-amplifier (BM-PA) that removes all dc-offsets present in the BM-TIA signal and regenerates the logical amplitude information. The BM-TIA is fabricated in a 0.25mum SiGe BiCMOS technology. The TIA is mounted together with a PIN photodiode in a butterfly package. These measurements show that the gain locking happens within 4.5ns from the start of the burst.