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User Friendly Optical Sources

Objective

The main technical objective of the project is to develop optical sources which will meet IBC requirements.

The project will mainly address the l.55 um wavelength range, using materials in the InGaAsP system. These will be fabricated using MOVPE, exploiting quantum well and strained layer structures. All optical sources developed will be aimed for single frequency operation.

A further main goal of the project is to ensure the early availability of advanced pre-production optical sources for use in systems experiments within the RACE Programme.
The main technical objective of the research was to develop optical sources which will meet integrated broadband communications network (IBCN) requirements. The project mainly addresses the 1.55 um wavelength range, using materials in the indium gallium arsenide phosphorus system. These are fabricated using metal organic vapour phase epitaxy (MOVPE), exploiting quantum well and strained layer structures. All optical sources developed will be for single frequency operation. A further main goal of the research was to ensure the early availability of advanced preproduction optical sources for use in systems experiments.

Improved single mode yield and increased spectral uniformity and reproducibility leading to lower cost single frequency lasers;
simplified coupling and selfaligned packaging;
devices with a wide continuous tuning range;
devices with a very wide wavelength coverage;
systematic design, including the realization of a comprehensive computer aided design (CAD) package;
integration of advanced optical sources with broadband transmission and switching equipment.

Among the achievements in the first year of the research:
laser structures using semiinsulating regrowth for improved high speed performance;
gain coupled distributed feedback (DFB) lasers with high single mode yield and high spectral purity;
identification of structures automated wavelength selection and control of distributed Bragg reflector (DBR) lasers;
a 3 section DFB laser, using strained layer quantum wells, with very narrow linewidth;
progress in lasers with very wide tuning range;
draft specification of a coherent asynchronous transfer mode (ATM) line card, including detailed specification of transmit and longitudinal optical (LO) lasers.
Technical Approach

Devices with improved characteristics with regard to power, high temperature performance, bandwidth and packaging will be designed, fabricated and assessed. The optimisation will involve both the grown active region structure and current confinement within the device structure. Advanced grating designs and fabrication methods will be implemented leading to improved single mode yield, increased spectral uniformity and improved reproducibility.

Lasers with wide continuous tuning will be developed, including the implementation of control schemes for simplified practical application of tuneable lasers. Other lasers with a very wide wavelength coverage by electrical tuning will be developed using new device structures.

Combinations of performance requirements due to system demands will be taken into account and problems associated with optical interfacing will be addressed. The modelling and design effort will include the realisation of a comprehensive CAD package to be used for design of advanced lasers. A line card will be designed and fabricated with coherent optical and ATM electrical interfaces.

Key Issues

- Improved semiconductor laser structures for higher power and operation at higher temperatures.
- Improved single mode yield, and increased spectral uniformity/reproducibility leading to lower cost single frequency lasers.
- Simplified coupling and self aligned packaging.
- Devices with a wide continuous tuning range.
- Devices with a very wide wavelength coverage.
- Systematic design, including realisation of a comprehensive CAD package.
- Integration of advanced optical sources with broadband transmission and switching equipment.

Expected Impact

The most important impact of the project will result from cost reductions brought about by realisation and implementation of high yield designs and processes and by development of new device structures. Optical sources developed under this project will also impact on general systems and system design through: increased environmental tolerance; higher output power (allowing higher splitting factors); availability of lasers specifically designed for use in coherent systems and in WDM applications.

Coordinator

SIEMENS AG
Address
Otto-hahn-ring 6
81730 München
Germany

Participants (7)

GEC Marconi Materials Technology Ltd
United Kingdom
Address
Caswell
NN12 8EQ Towcester
Gayton Photonics Ltd
United Kingdom
Address
6 Baker Street
NN7 3EZ Gayton
Heinrich-Hertz-Institut fuer Nachrichtentechnik Berlin Gmbh
Germany
Address
Einsteinufer 37
10587 Berlin
IMEC V.Z.W.
Belgium
Address
Kapeldreef 75
3001 Leuven
NED. PHILIPS BEDRIJVEN BV
Netherlands
Address
Prof Holstlaan 4
5656 AA Eindhoven
SWEDISH INSTITUTE OF MICROELECTRONICS
Sweden
Address

164 21 Kista
TELEFONICA
Spain
Address
Emilio Vargas, 6
28043 Madrid