Abstract: Simultaneous oscillation of 23 wavelengths, spaced at 100 GHz, is demonstrated from a single
source using a semiconductoropticalamplifier linear cavity. The wavelength comb is generated from an
intra cavity, fiber implemented Lyot filter. Each oscillating wavelength has a linewidth of 12.5 GHz and
the maximum power variation between the 23 wavelengths was less than 3 dB.
Abstract: We demonstrate a highly stable, all-polarization-maintaining
fiber semiconductor ring laser source. It uses a semiconductoropticalamplifier (SOA) to provide both gain and gain modulation from an external
5-GHz optical pulse train. The laser source generates 3.5-ps pulses
up to a 50-GHz repetition rate with negligible amplitude pattern.
Abstract: We demonstrate a novel approach in the implementation of a broadband Optical Network Unit
using a SemiconductorOpticalAmplifier-based Optical Loop Mirror, both experimentally and via
simulations for up to 50 km and 2.5 Gb/s.
Abstract: We demonstrate a simple method for upgrading the repetition rate of 10 GHz optical sources to 40 GHz. It employs a Fabry-Perot filter and the saturation properties of a SemiconductorOpticalAmplifier.
Abstract: Packet clock generation from flag bits is demonstrated, using a Fabry-Perot filter followed by a semiconductoropticalamplifier. Ten clock pulses are generated from a single pulse with less than 0.45 dB amplitude modulation.
Abstract: This paper reviews the work performed under the
European ESPRIT project DO_ALL (Digital OpticAL Logic
modules) spanning from advanced devices (semiconductoropticalamplifiers) to all-optical modules (laser sources and gates) and
from optical signal processing subsystems (packet clock recovery,
optical write/store memory, and linear feedback shift register) to
their integration in the application level for the demonstration of
nontrivial logic functionality (all-optical bit-error-rate tester and
a 2 2 exchange–bypass switch). The successful accomplishment
of the project¢s goals has opened the road for the implementation
of more complex ultra-high-speed all-optical signal processing
circuits that are key elements for the realization of all-optical
packet switching networks.
Abstract: In this paper, a novel configuration is proposed for
the implementation of an almost all-optical switch architecture
called the scheduling switch, which when combined with appropriate
wait-for-reservation or tell-and-go connection and flow
control protocols provides lossless communication for traffic
that satisfies certain smoothness properties. An all-optical 2 2
exchange/bypass (E/B) switch based on the nonlinear operation
of a semiconductoropticalamplifier (SOA) is considered as the
basic building block of the scheduling switch as opposed to active
SOA-based space switches that use injection current to switch
between ON and OFF states. The experimental demonstration of
the optically addressable 2 2 E/B, which is summarized for
10–Gb/s data packets as well as synchronous digital hierarchy
(SDH)/STM-64 data frames, ensures the feasibility of the proposed
configuration at high speeds, with low switching energy and low
losses during the scheduling process. In addition, it provides
reduction of the number of required components for the construction
of the scheduling switch, which is calculated to be 50% in the
number of active elements and 33% in the fiber length.
Abstract: All-optical gate control signal generation is demonstrated
from flag pulses, using a Fabry–P{\'e}rot filter followed by
a semiconductoropticalamplifier. Ten control pulses are generated
from a single flag pulse having less than 0.45-dB amplitude
modulation. By doubling or tripling the number of flag pulses, the
number of control pulses increases approximately by a factor of
two or three. The circuit can control the switching state of all-optical
switches, on a packet-by-packet basis, and can be used for
nontrivial network functionalities such us self-routing.
Abstract: In this paper we discussed different switch architectures. We focus mainly on optical buffering. We investigate an all-optical buffer architecture comprising of cascaded stages of quantum-dot semiconductoropticalamplifier- based tunable wavelength converters, at 160 Gb/s. We also propose the optical buffer with multi-wavelength converters based on quantum-dot semiconductoropticalamplifiers. We present multistage switching fabrics with optical buffers, where optical buffers are based on fibre delay lines and are located in the first stage. Finally, we describe a photonic asynchronous packet switch and show that the employment of a few optical buffer stages to complement the electronic ones significantly improves the switch performance. We also propose two asynchronous optical packet switching node architectures, where an efficient contention resolution is based on controllable optical buffers and tunable wavelength converters TWCs.
Abstract: The authors demonstrate an optical buffer architecture which is implemented using quantum dot semiconductoropticalamplifiers (QD-SOAs) in order to achieve wavelength conversion with regenerative capabilities, for all optical packet switched networks. The architecture consists of cascaded programmable delay stages that minimise the number of wavelength converters required to implement the buffer. Physical layer simulations have been performed in order to reveal the potential of this scheme as well as the operating and device parameters of QD-SOA-based wavelength converters. The results obtained have indicated that, up to three time-slot interchanger (TSI) cascaded stages show good performance at 160 Gb/s in the 1550 nm communication window.
Abstract: The objective of this research is to propose two new optical procedures for packet routing and forwarding in the framework of transparent optical networks. The single-wavelength label-recognition and packet-forwarding unit, which represents the central physical constituent of the switching node, is fully described in both cases. The first architecture is a hybrid opto-electronic structure relying on an optical serial-to-parallel converter designed to slow down the label processing. The remaining switching operations are done electronically. The routing system remains transparent for the packet payloads. The second architecture is an all-optical architecture and is based on the implementation of all-optical decoding of the parallelized label. The packet-forwarding operations are done optically. The major subsystems required in both of the proposed architectures are described on the basis of nonlinear effects in semiconductoropticalamplifiers. The experimental results are compatible with the integration of the whole architecture. Those subsystems are a 4-bit time-to-wavelength converter, a pulse extraction circuit, a an optical wavelength generator, a 3 x 8 all-optical decoder and a packet envelope detector.
Abstract: We demonstrate an optical power limiter using a
semiconductoropticalamplifier (SOA)-based interferometric gate
powered by a strong continuous-wave input signal. We present a
detailed theoretical and experimental investigation of the power
limiting characteristics of saturated SOA-based switches, showing
good agreement between theory and experiment.
Abstract: We present methods for obtaining high-repetition-
rate full duty-cycle RZ optical pulse trains from lower rate
laser sources. These methods exploit the memory properties of the
Fabry–Perot filter for rate multiplication, while amplitude equalization
in the output pulse train is achieved with a semiconductoropticalamplifier or with a second transit through the Fabry–Perot
filter.We apply these concepts to experimentally demonstrate rate
quadruplication from 10 to 40 GHz and discuss the possibility of
taking advantage of the proposed methods to achieve repetition
rates up to 160 GHz.
Abstract: This paper presents a theoretical and experimental
analysis of saturated semiconductoropticalamplifier (SOA)-based
interferometric switching arrangements. For the first time, it is
shown that such devices can provide enhanced intensity modulation
reduction to return-to-zero (RZ) formatted input pulse trains,
when the SOA is saturated with a strong continuous-wave (CW)
input signal. A novel theoretical platform has been developed in
the frequency domain, which reveals that the intensity modulation
of the input pulse train can be suppressed by more than 10 dB at
the output. This stems from the presence of the strong CW signal
that transforms the sinusoidal transfer function of the interferometric
switch into an almost flat, strongly nonlinear curve. This
behavior has also been verified experimentally for both periodically
and randomly degraded, in terms of intensity modulation,
signals at 10 Gb/s using the ultrafast nonlinear interferometer as
the switching device. Performance analysis both in the time and
frequency domains is demonstrated, verifying the concept and its
theoretical analysis.
Abstract: A novel method for the multiplication of the repetition
rate of full duty-cycle return-to-zero optical sources is presented.
It employs the memory property of a Fabry–P{\'e}rot filter
for the multiplication task, combined with the gain saturation of a
semiconductoropticalamplifier for amplitude equalization. This
concept has been applied to quadruplicate the rate of a distributed
feedback laser source operating at 10 GHz.
Abstract: We present recent advances in multi-wavelength, power-equalized laser sources that incorporate a semiconductoropticalamplifier (SOA) and simple optical filters, such as Lyot-type and Fabry-Perot, for comb generation. Both linear and ring-cavity configurations are presented, and single-pass optical feedback technique is proposed to improve the performance in terms of the number of simultaneously oscillating lines and output channel power equalization. This technique resulted in a broadened oscillating spectrum of 52 lines spaced at 50 GHz, power-equalized within 0.3 dB. Finally, a simplified version that uses only an uncoated SOA for both gain and comb generation is demonstrated.
