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Integrated Optoelectronics on InP

Objective

For five years, up to its termination in 1989, project 263 was the flagship optoelectronics project supported under ESPRIT. Composed of two groups, the project aims were to develop integrated wavelength multiplexed transmitter and receiver chips (group A), and to integrate lasers and detectors with transistor drivers and pre-amplifiers (group B).
Composed of 2 groups, the project aims were to develop integrated wavelength multiplexed transmitter and receiver chips (group A), and to integrate lasers and detectors with transistor drivers and preamplifiers (group B).

A focal point of the group A collaboration has been the optoelectronic device simulation facility.
Low loss waveguide bends, fabrication tolerant power splitters and novel wavelength filters and demultiplexers were generated using this unique facility, and many practical problemsof integrated addressed. Group B has concentrated on the development of the 2 key components required in any optical transmission system, namely the optical transmitter and the optical receiver. The main innovation of this work has been the combining of both the optical (laser of photodetector) and electronic (transistor) devices on the same semiconductor chip, an approach which offers the prospect of higher performance, lower cost, reduced sized and improved reliability compared with more conventional hybrid components.
The project made remarkable progress, and has helped to establish the technology being deployed under the RACE programme by demonstrating some of the key components required for optical broadband communication networks throughout Europe.
Integrated optoelectronics demands precise control of the semiconductor alloys grown in layers to make lasers, detectors and optical waveguides. ESPRIT 263 has strengthened the key technologies in this area, moving from LPE to MOVPE and MBE for growing InP-based compounds on InP substrates. Not only has this resulted in large area wafers of reliable composition and reproducible thickness, but losses in waveguides have fallen by a factor of ten.
Group A's work on integrated transmitters has explored the fabrication of laser sources operating at two wavelengths separated by 30 nm around 1.55 micron. Either direct or external modulation is used to encode digital information onto these optical carriers, which are combined onto a single fibre using a wavelength division multiplexer. The receiver comprises a wavelength demultiplexer to separate the two optical carriers, together with integrated photodetectors to convert the signal back into electricalform.
In developing the transmitter components, STL and CGE have improved their narrow linewidth DFB lasers and demonstrated the ability to fabricate sources operating at different wavelengths on the same chip using direct-write E-beam lithography and localised epitaxy. Thomson-CSF has produced integrable modulators and wavelength multiplexers with channel spacing down to 12 nm. All three partners have also integrated laser sources with optical waveguides on the same chip. Using the InGaAlP material system, CSE LT have produced demultiplexers with channel spacings close to the required 30 nm and integrated high-speed (>4 Gbit/s) detectors.
A focal point of the Group A collaboration has been the optoelectronic device simulation facility, developed by GEC-Marconi largely under this programme. Sophisticated numerical techniques have been harnessed using interactive graphic interfaces to provide user-friendly engineering tools, which enable a rapid convergence towards, and verification of, the required design. Low-loss waveguide bends, fabrication-tolerant power splitters and novel wavelength filters and demultiplexers were generated using thisunique facility, and many practical problems of integration addressed. Excellent agreement has been found with the experimental result.
Group B has concentrated on the development of the two key components required in any optical transmission system, namely the optical transmitter and the optical receiver. The main innovation of this work has been the combining of both the optical (laser of photodetector) and electronic (transistor) devices on the same semiconductor chip, an approach which offers the prospect of higher performance, lower cost, reduced size and improved reliability compared with more conventional hybrid components. Excellent progress has been achieved within the project. Two different approaches to the transmitter integration have been developed. The major thrust has been towards integrating the semiconductor laser with a heterojunction bipolar transistor, however, the most successful approach to date has been the integration of the laser with an insulated gate transistor. Successful operation at 1.12 Gbit/s has been demonstrated for a hybridised module containing an integrated heterojunction bipolar transistor driver circu t and a high-speed laser.
The integrated receiver activity within Group B has achieved world-record results. The group has fabricated the most sensitive receiver at 560 Mbit/s with a figure of 32.7 dBm. This circuit comprises an indium gallium arsenide pin photodiode integrated alongside a heterojunction field-effect transistor. These same devices have also been combined into a full transimpedance receiver design with a state-of-the-art integration level of 17 components and operation at up to 2.4 Gbit/s.
Exploitation
The technology developed under ESPRIT 263 is already being exploited under RACE, where high-quality lasers, optoelectronic ICs, low-loss waveguides, etc, are being incorporated into a range of exploratory communication systems and optically switched networks. Beyond this lies a new generation of telecommunications, instrumentation and signal processing applications.

Coordinator

Centro Studi e Laboratori Telecomunicazioni SpA
Address
Via G. Reiss Romoli, 274
10148 Torino
Italy

Participants (6)

Alcatel Alsthom Recherche
France
Address
Route De Nozay
91460 Marcoussis
Centre National d'Études des Télécommunications (CNET)
France
Address
196 Avenue Henri Ravera
92220 Bagneux
GEC Marconi Research Centre
United Kingdom
Address
West Hanningfield Road Great Baddow
CM2 8HN Chelmsford
Heinrich-Hertz-Institut fuer Nachrichtentechnik Berlin Gmbh
Germany
Address
Einsteinufer 37
10587 Berlin
Standard Elektrik Lorenz AG (SEL)
Germany
Address
Lorenzstraße 10
70435 Stuttgart
Thomson CSF
France
Address
Domaine De Corbeville
91404 Orsay