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: 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: 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: 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: 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: 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.