Ben Puttnam

Nanosecond channel-switching exact optical frequency synthesizer using an optical injection phase-locked loop (OIPLL)

Experimental results are reported on an optical frequency synthesizer for use in dynamic dense wavelength-division-multiplexing networks, based on a tuneable laser in an optical injection phase-locked loop for rapid wavelength locking. The source combines high stability (<1-kHz channel frequency error over 5-K temperature change), with high output power (/spl sim/2dBm), wide tuning range (40 nm), high spurious suppression (>50 dB), narrow linewidth (10 MHz), and fast wavelength switching (<10 ns).

Burst mode operation of a DS-DBR widely tunable laser for wavelength agile system applications

Novel measurements of signal Q-factor as function of time across an optical burst and implementation of fast control system, giving 3 orders of magnitude switching speed and 5 fold stability improvements on previous DS-DBR measurements, are described.

Nanosecond tuning of a DS-DBR laser for dynamic optical networks

Fast switching, widely tunable semiconductor lasers will be essential in dynamic wavelength provisioning in future optical networks where data is transmitted in optical bursts or packets ranging from 100ns to 100ms at standard ITU-T wavelengths [1]. Of the several designs proposed, the Digital Super-mode-Distributed Bragg Reflector (DS-DBR) is of particular interest since it is able to cover its full tuning range with high (13 dBm) and uniform output power and Side Mode Suppression Ratio (SMSR) (≪30 dB), using significantly lower tuning currents, thus, reducing wavelength error from thermal transients and noise from current sources. Previously, DS-DBR has been used in burst transmitter (BTx) demonstrations employing wavelength locking (WL) and SOA blanking, to remove the spurious modes that are generated during the switching transition, on the µs-ms timescale [2, 3]. Here, we describe the nanosecond switching characteristics and demonstrate full BTx functionality, required for future optical burst switched networks, for the first time.

Dynamic optical network architectures for future IP traffic

Current optical transport networks provide high bandwidth through the use of advanced WDM technology, but are difficult to adapt to the different statistical patterns and quality of service (QoS) demands of future traffic. There has been much debate whether the use of dynamically reconfigurable optical networks would have a number of advantages in accommodating the needs of future traffic demands. Dynamic networks would eliminate the need for frequent opto-electronic conversion in current networks, and may save resources through higher utilization and fast adaptation. Different architectures have been proposed to address this problem: Wavelength-routed optical networks (WRON), optical burst switching (OBS), and optical packet-switching (with increasing granularity and speed of reconfiguration). In this paper we investigate whether these architectures are suitable (necessary?) to meet the demands of future traffic, using an analysis focusing on both modeling and experimental aspects.