PROaccess : a passive-components-based reconfigurable WDM-TDM optical access network

The evolution of optical access networks have focused on improving their transmission capacity by increasing transmission bit rate per wavelength and number of wavelengths per fibre. However, the huge aggregated capacity is composed by separate bandwidth pools in which each wavelength channel is an independent pool. As a result, some wavelengths may be congested while others are underutilization. In order to allow the system capacity to be a single bandwidth pool, the wavelength reconfigurability is required in which an user can be relocated to another wavelength if the current wavelength is congested. Adding reconfigurable feature also adds complexity, hence CAPEX and OPEX to the networks. Therefore, networks operators up to now have been reluctant despite of benefits of the flexible bandwidth delivery. In this paper, we propose a cost-effective, reconfigurable optical access network by employing passive network components in the remote node and dual conventional optical transceivers in ONUs. The novel approach allows outside plant totally passive and ONUs without tunable filters and lasers. Despite of using only passive and non-tunable components, it still attains a superior flexibility. The architecture is demonstrated with the bidirectional transmission at 10 Gb/s symmetrically

DMT based multi-Gbit/s communication in indoor optical networks using R-SOA

After ‘fiber to the home’, fiber has reached in the room. To make such fiber based indoor networks cost and energy efficient, reflective modulators (like R-SOA and REAM) are core components which are also wavelength agile. They remove the need of laser sources at antenna access points for upstream signal. The baseband version of OFDM (i.e. DMT) along with bit-and power-loading algorithm can overcome the bandwidth limitation of R-SOA. In this paper, we have shown experimental results of multi-gb/s communication for upstream signal in indoor optical networks. DMT modulation scheme has been used to obtain throughput of 9 Gb/s with a 750MHz RSOA

Optical generation of IR-UWB pulse based on weighted sum of modified doublets

We propose a relatively simple optical generation concept for impulse radio ultra wideband (IR-UWB) pulse over fiber transmission using a weighted sum of a modified doublet with its inverted and delayed version. The generated pulses not only fi4ly comply with the FCC spectral mask but also are highly power efficient in the available spectrum. We verified our approach using both simulation and experimental demonstration. The concept has a potential to be integrated with other optical functions on a compact optical chip, making it very suitable for wide UWB deployment for highspeed wireless access at low costfor in-building network applications

Performance comparison of multi-wavelength conversion using SOA-MZI and DSF for optical wavelength multicast

The electronic layer multicast is going to face the speed and capacity bottleneck of the future optical data networks. Transparent optical wavelength multicast by multi-wavelength conversion is an effective way of achieving data multicast in the optical domain without any optical-electronic-optical conversion. In this paper, two multiple wavelength conversion technologies for 10 Gb/s data rate are investigating and discussed. The first technology is based on cross-phase modulation in a semiconductor optical amplifier – Mach-Zehnder interferometer, and the second is based on four-wave mixing in a dispersion-shifted fiber. We present the simulated performance comparison of two approaches obtained using VPItransmissionMakerTMWDM simulator. Afterwards, we analyze these results in comparison with our previous experimental results of the same schemes

Optimization of existing access networks with low-cost multilevel modulation formats

PON networks are designed around a minimum received power level. The actual use of power budgets in a PON typically varies widely. Utilizing multilevel modulation for ONUs that have high power margins can increase network capacity utilization without investing in expensive optics. In this paper we present statistics from a commercial GPON network and demonstrate that a capacity increase is possible for a majority of the users. Even users with a low power margin can benefit from multilevel modulation, if smart distribution of timeslots among users is utilized