Y. Shachaf

Multi-PON access network using a coarse AWG for smooth migration from TDM to WDM PON

An interoperable access network architecture based on a coarse array waveguide grating (AWG) is described, displaying dynamic wavelength assignment to manage the network load across multiple PONs. The multi-PON architecture utilizes coarse Gaussian channels of an AWG to facilitate scalability and smooth migration path between TDM and WDM PONs. Network simulations of a cross-operational protocol platform confirmed successful routing of individual PON clusters through 7 nm-wide passband windows of the AWG. Furthermore, polarization-dependent wavelength shift and phase errors of the device proved not to impose restrain on the routing performance. Optical transmission tests at 2.5 Gbit/s for distances up to 20 km are demonstrated.

Interoperability of GPON and WiMAX for network capacity enhancement and resilience

The interoperability of standard WiMAX and gigabit passive optical networks (GPONs) is shown to overcome the wireless spectrum congestion and provide resilience for GPON through the use of overlapping radio cells. The application of centralized control in the optical line terminal and time division multiplexing for upstream transmission enables efficient dynamic bandwidth allocation for wireless users on a single wavelength as well as minimized optical beat interference at the optical receiver. The viability of bidirectional transmission of multiple uncoded IEEE 802.16d channels by means of a single radio-frequency subcarrier at transmission rates of 50 and 15 Mbits/s downstream and upstream, respectively, for distances of up to 21 km of integrated GPON and WiMAX microcell links is demonstrated.

Evolution of Optical Access Networks

This chapter reviews the current developments in access network architectures and protocols to communicate dynamically the emerging broadband services to end-users at low cost. Following a summary of Gigabit Ethernet and Passive Optical Network (PON) standards and deployment issues with reference to Ethernet (EPON) and Gigabit-capable PON (GPON) infrastructures, an original transparent network architecture is presented to allow interoperability of time division multiplexing (TDM) and wavelength division multiplexing (WDM) PONs, by means of coarse routing. To provide flexible connectivity at extended service reach hybrid wireless and free space optic technologies have been investigated to terminate mobile end users to high bandwidth PON terminals. To demonstrate independent bandwidth management of the constituent sectors of such architectures developed dynamic bandwidth allocation (DBA) algorithms are summarised followed by an original control plane to coordinate the various mandatory access control (MAC) protocols. Finally, to provide reliable service delivery several protection schemes have been analysed.

Demonstration of Coarse-Fine Grooming in Coarse-WDM-Routed PONs

A scalable access network architecture is implemented experimentally to demonstrate gradual deployment of time- and wavelength-division-multiplexed passive optical networks (PONs) in a single-platform with minor changes in fiber infrastructure. This is achieved by the application of dynamic coarse-fine grooming to route multiple reflective optical network units of either time- or wavelength-multiplexed PONs collectively through coarse passbands of an arrayed waveguide grating (AWG). To evaluate experimentally the contribution of the excessive properties of wider-than-dense-passband AWGs to network performance, a readily available 2.7 nm device is utilized to substitute for 7 nm coarse-AWG prototypes. Experimental results have confirmed 10-9 bidirectional transmission of data and continuous waves over 2.7-nm-wide passband windows of the AWG in the presence of 0.35 nm polarization-dependent wavelength shift and 1.5 dB polarization-dependent loss. In addition, Rayleigh backscattering is reported to be incapable of limiting the network performance.

A Full-duplex Access Network based on CWDM-routed PONs

The application of polarisation-division-multiplexing in presented, demonstrating full-duplex transmission in an access network architecture employing RSOA-based ONUs. Modelling of a single coarse-AWG OLT to transmit orthogonally-multiplexed burst-data and continuous-waves demonstrated crosstalk-free transmission up to 20 km.

PON topologies for dynamic optical access networks

PON-based access networks envisage the demonstration of scalability to allow gradual deployment of time and wavelength multiplexed architectures in a single-platform without changes in fibre infrastructure and also highly-efficient bandwidth allocation for service provision and upgrade on-demand. This is achieved by the application of coarse-fine grooming to route reflective-ONUs of time and wavelength PONs collectively and the development of MAC protocols enabling the OLT to dynamically assign available time slots among ONUs and demonstrate efficient bandwidth and wavelength assignment.

In-band optical signal-to-noise ratio monitoring technique based on Brillouin fiber ring laser

We propose an improved technique for in-band optical signal-to-noise ratio (OSNR) monitoring based on a Brillouin fiber ring laser seeded by the optical channel to be monitored. This technique shows a reduction of the required input power into the monitor along with a large and tunable dynamic OSNR monitoring range. It is demonstrated experimentally and numerically for various bit rates and modulation formats.

Brillouin fiber ring laser based in-band OSNR monitoring method for transparent optical networks

We propose a novel approach for in-band OSNR monitoring based on the Brillouin fiber ring laser seeded by the optical channel to be monitored. This technique is demonstrated experimentally and numerically for various bit rates and modulation formats and shows a reduction of the required input power into the monitor along with a large and tunable dynamic monitoring range.

Multi-PON access/metro network using a coarse-WDM AWG router

A novel access/metro network architecture based on a coarse wavelength division multiplexing array waveguide grating router, supporting multiple passive optical networks (PONs) in the downstream and switching up to 32 optical network units (ONUs) per PON over coarse wavelength bands is described. The cost effective network architecture is simulated, using a physical-layer model of two PONs, each comprising 16 ONUs, employing 12nm-wide passband windows in the array waveguide grating. In this manner low error rate transmission at 2.5 Gbit/s for distances up to 20 km is demonstrated.