A.J. Boot

The polarization properties of stimulated brillouin scattering (SBS) in low birefringent optical fibers were evaluated using Stokes calculus. It was found that the Brillouin gain for orthogonally polarized pump and probe wave is half (in dB) of the gain for identical polarization, and not equal as often mentioned in literature. Therefore the polarization factor is K=11/2 for complete polarization scrambling, and not K=2. The spontaneous SBS has the same state of polarization as the pump, and its degree of polarization is 33.3% for low pump powers and near 100% for high pump powers. The experimental results agree very well with the calculations

In case of a large number of channels and a limited available optical bandwidth (limited laser tuning range) it may be necessary to chose a channel spacing near 0 or 11 GHz, where Rayleigh-and Brillouin backscattering introduce crosstalk in a bidirectional system. Although there is much literature on stimulated Brillouin scattering, that occurs at high powers, there is hardly any attention paid to what happens at relatively low input powers. Furthermore there are no system measurements which thoroughly investigate these effects. The authors performed extensive bidirectional system experiments to investigate the crosstalk from Brillouin scattering in more detail, including its polarization properties. They found, that, while for high powers most of the energy is backscattered to a 11 GHz lower frequency, for low powers there is no difference for the crosstalks at 11 GHz higher or 11 GHz lower than the signal frequency. The power budget is limited to 40 dB for both cases. The predicted 33.3% degree of polarization of low-power Brillouin scattering is experimentally confirmed for the first time.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Successful WDM transmission of four 10 Gbit/s channels ranging from 1310.5 nm to 1317.4 nm over 80 km was demonstrated. Based on these results and simulations using a time resolved SOA model, we expect to reach 4/spl times/10 Gbit/s transmission over at least 200 km.

This paper presents different architectures for high split, wide range bidirectional SuperPONs.One of the ways to achieve such SuperPONs is by the introduction of erbium- doped-fiber-amplifiers or semiconductor optical amplifiers (SOA) in order to overcome the strongly increased power budgets in comparison to conventional PONs. This will however present new challenges in overcoming the 'noise- funneling' effect caused by the parallel amplifiers. Four different approaches are studied: 1) using of on/off switchable semiconductor optical amplifiers, 2) using parallel erbium-doped-fiber amplifiers, 3) using electro- optic regeneration, and 4) using conventional SDH, ATM and APON technology. A description is given of each architecture, including advantages and drawbacks. These architectures serve as input to further studies performed by the ACTS-PLANET consortium. The power-budget studies showed that it is technically feasible to develop a SuperPON with a 2048 split and a 70-100 km range.

Using an 1309 nm RZ transmitter at 10 Gbit/s and a chain of semiconductor optical amplifiers a record high transmission capacity of 4200 Gbit-km/s has been established. RZ 10 Gbit/s transmission at 1309 nm over a 420 km standard single mode fibre link with lumped amplification is demonstrated. A total of 12 multiple quantum well optical amplifiers were used to compensate for the fibre losses.