J.J. Lepley

Dispersion-tolerant transmission using a duobinary polarization-shift keying transmission scheme

We demonstrate a novel dispersion-tolerant transmission scheme based on a three-level duobinary-encoded polarization-shift keying (PoISK) transmission format. Simulations over standard single-mode fiber demonstrate an improvement in the chromatic dispersion-limited transmission distance from /spl sim/65 km, using conventional nonreturn to zero intensity modulation to /spl sim/195 km for duobinary PoISK.

VDSL transmission over a fiber extended-access network

Feature Issue on Optical Access Networks (OAN) We describe two schemes developed to carry very-high-data-rate DSL (VDSL) signals over a fiber to the cabinet architecture for the upgrade of legacy copper networks. The first technique exploits the subcarrier bandwidth of uncooled semiconductor lasers for the transmission of multiple VDSL signals by using inexpensive interfacing hardware in the optical network unit (ONU). With a hybrid fiber-copper link comprising 100 m of twisted-pair copper cable and as much as 45 km of single-mode fiber, data transmission comparable with that for fiber to the home is achieved. In an extension to this design we demonstrate a system using a reflective semiconductor optical amplifier in a carrierless remote ONU configuration. Such a design might provide wavelength agility in the fiber access network for signal routing or active bandwidth allocation.

Enhanced Transmission Techniques

Next generation Passive Optical Networks (ngPONs) that offer increased bandwidth and distance-reach to a higher number of customers may require some modifications in the network infrastructure and in the technology of its devices. Nevertheless, these changes should not require a significant increased cost nor upgrading complexity. Optical Network Units (ONUs) at customer premises of currently deployed PONs include a fixed laser at a non-controlled wavelength, launching the light into the upstream fibre or into a single fibre via a coarse WDM multiplexer. In future PONs, Wavelength division multiplexing (WDM) can be effectively used to upgrade the overall PON capacity in several ways. Thus, new generation ONUs may be wavelength-controlled, wavelength-tuneable or wavelength-agnostic. WDM allows superposing different TDMA PONs over the access fibre line. The number of wavelengths then corresponds to two times the number of TDMA PON systems. This solution offers desirable characteristics for an access infrastructure as the use of one single fibre for both upstream and downstream transmission reduces the network size and connection complexity.

Experimental Demonstration of a Macroscopic Cryptography Technique

Physical layer cryptography offers the unique possibility of certifiably secure data transmission between remote locations. We present here for the first time, to our knowledge, the experimental results of a secure full Poincare occupancy polarization encrypted data transmission system. The scheme uses an approach to macroscopic physical layer cryptography based on combining a multilevel polarisation modulation cipher with a differential phase shift keying data transmission technique. Depolarized noise is added to the encrypted data so as to hide both the data and key from a potential eavesdropper. Experimental results prove the effectiveness of the technique over amplified optical transmission links. The technique hence opens up new avenues for long distance secure data transmission over fibre links

Stokes Encrypted Secure Communication over Optically Amplified Links

We describe an innovative polarization-based optical fibre physical layer cryptography technique capable of highly secure data transmission over amplified optical links. It offers completely opaque communication over trans-oceanic distances, gigabit date rates and multiple wavelengths.

An accurate numerical model for distributed Raman amplifiers

We present, for the first time, a complete numerical analysis of Raman amplifiers including pump depletion and higher-order Stokes wave generation. Raman gain and OSNR in co-propagating, counterpropagating and bi-directionally pumped FRAs are examined.

VDSL transmission over Latin routed DWDM optical access networks

We present a novel architecture for sub-carrier multiplexed VDSL transmission utilising cascaded arrayed-waveguide grating optical access network. In particular, triple play was achieved with both DMT and QAM based VDSL modems.

VDSL over fibre access network with reflective optical network unit

We demonstrate a system using a reflective semiconductor optical amplifier (RSOA) in a carrier-less remote ONU configuration in an FTTC scenario. Band-plan agnostic VDSL transmission over 20 km single-mode fibre was achieved. The described sub-carrier multiplexed high density network topology based on AWG is upgradeable to FTTH without major physical infrastructure change due to the ONUs inherent wavelength independent characteristic. The passive nature of the optical link makes this architecture easily deployable and a cost effective solution for the present bandwidth hungry market.

Polarization shaped duobinary transmission scheme

We present a novel duobinary transmission scheme exhibiting a symmetrical eye degradation and tolerance to chromatic dispersion and fiber nonlinear effects. Simulations show that the maximum attainable dispersion-limited transmission distance for 10-Gb/s data over standard single-mode fiber can be extended to 160 km for a 1-dB eye closure penalty. We compare the performance of this scheme with phase-shaped duobinary transmission, and conclude that in a practically realizable system, polarization-shaped duobinary will perform better.

Interoperability of Last Mile Access Technologies over a Passive Optical Ring Network: Results of the MUSE Demonstration

We demonstrate simultaneous operation of FWA, FTTP and FTTCab/DSL solutions over a common passive CWDM ring network platform; verifying the potential coexistence of multiple deployment scenarios for high bandwidth delivery in future access networks.