Transcript Signal processing in high-capacity systems

COST 267
Semiconductor devices for optical
signal processing
Sep. 1998 – June 2002
TC-TIST meeting, Thessaloniki, June 2002
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Pulsed
laser
Regeneration
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Demux
Signal processing in high-capacity systems
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Optical gate
Electronic bottlenecks may be avoided by the use of
all-optical signal processing: switch light with light
control
signal to switch
output
“AND” gate can
be
implemented in a
nonlinear device
Background
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Wavelength Division Multiplexing is used to increase the
network capacity. Optical Time Division Multiplexing is a
promising technique for increasing the bitrate beyond 40
Gbit/s, which is the practical limit set by electronics today.
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By performing processing in the optical rather than the
electrical domain, the bit rate may be increased. Also there
may be advantages in terms of flexibility, management
issues and price.
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Devices based on semiconductors, and in particular on
active semiconductors devices (lasers and amplifiers), are
very suitable for all optical processing - they are compact
and have strong optical nonlinearities.
TC-TIST meeting, Thessaloniki, June 2002
Signal processing using optical amplifier
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The gain of the amplifier can be controlled optically
TC-TIST meeting, Thessaloniki, June 2002
Objectives
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Development and application of measurement techniques to
determine the suitability of active photonic semiconductor
components for optical signal processing
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Development and application of modeling methods for
nonlinear active semiconductor components. Analysis of
experimental results – towards tools for design and
optimization.
TC-TIST meeting, Thessaloniki, June 2002
Action data
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Start: September 30, 1998. End: September 29, 2002
17 Signatory countries.
5 non-COST countries participating.
14 short term missions (3 more expected before Sep. 2002)
42 publications (papers and conference contributions)
8 management committee meetings, 6 WG meetings
3 open workshops (50 – 100 participants)
TC-TIST meeting, Thessaloniki, June 2002
Topics considered
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Comparison of bulk, quantum well, quantum wire and quantum dot materials
for all-optical ultrafast processing;
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Development of design criteria for components and integrated subsystems in
respect to a particular functionality;
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Study of ultrafast all-optical demultiplexing based on cross-gain, cross-phase
and four-wave mixing in semiconductor optical devices. Comparison of these
schemes, as well as comparison to other techniques (e.g. electroabsorption
modulators);
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Study of the potential offered by all-optical devices based on cross-phase,
cross-gain modulation and four-wave mixing, and comparison of their
performance with the requirements of the various possible configurations for
WDM and TDM networks;
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Study and design of semiconductor devices for the generation and the control
of ultrafast optical pulses.
TC-TIST meeting, Thessaloniki, June 2002
Organization
WG1
Modeling
Compare models
Common exercises
- Pulse propagation
- Fast dynamics
- Interferometers
WG2
Characterisation
WG3
Fabrication
Compare measurements
Round-robin exercise
- Pulse saturation
- Pump-probe meas.
- SOAs
Design
Fabrication
Devices for r-r exercise
TC-TIST meeting, Thessaloniki, June 2002
Organization ... dynamics
Two phases:
I: Sep. 1998 – Oct. 2000
Action chairman
Action vice chair
WG1 chair
WG1 vice chair
WG2 chair
WG2 vice chair
WG3 chair
WG3 vice chair
II: Oct. 2000 – Sep. 2002
New
New (from May 2001)
New
New
New..... + second change
New..... + second change
WG3 merged with WG2
Many key persons changed to start-ups in spring 2000.
Decided to continue action – emphasis on STMs, workshop.
TC-TIST meeting, Thessaloniki, June 2002
Economic dimension
Budget of approximately 50 kEURO per year.
In 2001, an unspent amount of 20 kEURO was
returned to Brussels.
Reasons: Decreased level of activity and very late
arrival of grant (1 month before end of grant period).
Main part of budget spent on:
Reimbursement of MC members
Short term missions
Invited speakers at workshops
TC-TIST meeting, Thessaloniki, June 2002
Workshops
COST 267 workshop ”Semiconductor Devices for Optical Signal
Processing”, 50 participants (Rome, April 22, 1999)
Common COST 266-267 workshop “Optical Signal Processing in
Photonic Networks”, 100 participants (Berlin, April 5 – 7, 2000)
COST 267 / International workshop “Optical Signal Processing”,
80 participants (Kgs. Lyngby, Nov. 29–30, 2001)
Common ACTS/COST 267-268 workshop “Advanced Photonic
Components and Subsystems” organized by the ACTS project
HORIZON (Brussels, May 5, 1999)
Proceedings of the workshops are available (through Website for
Berlin and Lyngby workshops)
Short term missions
H. Soto, from ENST Paris to ETH Zurich.
October 1999
Laurent Schares, from ETH Zurich to Nat. Tech., Athens.
November 1999
Lorenzo Occhi, from ETH Zurich to HHI Berlin.
January 2000
Laurent Schares, from ETH Zurich to HHI Berlin.
January 2000
Kresten Yvind, from Research Center COM to HHI Berlin.
April 2000
Hovik Baghdasaryan, from Fern University to U. Politech.Valencia .
April 2000
George Toptchiyski,from TU Berlin to Research Center COM
September 2000
Ricardo Scollo, from Politecnico Milan to ETH Zurich
June 2001
Mariangela Gioannini, from Politecnico di Torino to HHI Berlin
June 2001
Jan de Merlier, from IMEC Gent to Research Center COM
August 2001
Laurent Schares, from ETH to HHI Berlin
April 2002
Sean O’Duill, from Univ. College Dublin to Univ. Of Rome
May 2002
Mariangela Gioannini, from Politecnico di Torino to HHI Berlin
May 2002
Jan de Merlier, from IMEC Gent to Politecnico di Torino
June 2002
3 additional STMs are expected before end of action (Sept. 2002)
TC-TIST meeting, Thessaloniki, June 2002
Key results
Work well described by MoU – but less activity than anticipated.
WG1: Development and application of theoretical models for
describing pulse propagation and interferometer dynamics.
Inputs to pre-defined modelling exercise.
WG2: Round-robin exercises. 16 SOAs (10 MQW, 6 bulk) from 4
companies (JDS-Uniphase, Opto-Speed, Corning, Alcatel)
measured by 13 institutions.
Comparison of saturation effects (vs length, bulk/QW), recovery
times, propagation effects.
STMs: ... + Modelocked lasers for short pulse generation,
new devices for optical switching, ...
TC-TIST meeting, Thessaloniki, June 2002
TC-TIST meeting, Thessaloniki, June 2002
TC-TIST meeting, Thessaloniki, June 2002
Self-evaluation (preliminary)
Main successes:
Short Term Missions! Good for initiating collaboration.
Round-robin exercise; high quality devices, possibility for
comparison of measurements ... and new investigations.
Three well-attended workshops with invited talks.
Promising field – with consequences for COST activity.
Drawbacks
Active research field, where many groups are already preoccupied by (IST) projects (with ”real money”).
Too specific focus from the start – problem when
participation was downsized.
Key difficulties encountered
Change of organization – and reduction of participants.
Late arrival of grants.
Difficult to get full committment – salary would help.
New action?
Discussions between COST 267 and 268 on proposing a new action
within the photonics domain have been initiated.
Possible title: Nanoscale and ultrafast photonics
Study of ultrafast nanophotonics towards applications in the
high capacity photonic communication infrastructure;
forum to bring forward novel topics such as advanced optical
signal processing and exploratory technologies based on
nanophotonics
Topics of particular interest for COST 267 participants:
- high-frequency limits of lasers and amplifiers, ultrafast dynamics
- investigation and application of high-speed nonlinearities in
nanophotonic devices; quantum dot amplifiers
- novel concepts for switching in active semiconductor devices
Engineering of the material – quantum
dots
Atom
Semiconductor
Quantum Well
TC-TIST meeting, Thessaloniki, June 2002
Quantum dot
Quantum dot optical devices
Prospects:
- enhanced light-matter interaction
- control of material properties
- novel quantum devices
- improved laser properties - !
- high-speed amplifiers - ?
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