Work Area: Novel Concepts and New Materials for Optical Devices / All-Optical Computing
Keywords optical nonlinearities, electro-optics, quantum well microresonators
Start Date: 1 July 92 / Duration: 36 months / Status: running
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Abstract PHOTONS is studying the fundamental and technological challenges associated with quantum well microresonators (QWMs). QWMs show great potential for optoelectronic devices and applications such as vertical cavity surface-emitting lasers and nonlinear optical modulators and switches. Topics to be considered include strained and piezo-electric materials, barrier reservoir structures, asymmetric coupled and Type II quantum wells, and various technological issues in the growth and fabrication of QWM devices.
The objective of the group is to further the study of the physics, technology and applications of quantum well microresonators (QWMs) through discussion and an exchange of expertise. QWMs are formed when a layer of quantum well material is sandwiched between two Bragg stacks. QWMs have proven in the past to have a strong potential for optoelectronic devices and application such as vertical cavity surface emitting lasers (VCSELs) and electro-optic and nonlinear optical modulators and switches. This class of device is strategically important for optical interconnects, optical computing and reprographics. The current state-of-the-art is not sufficient when attempting to exploit these devices in optoelectronic systems. It is the aim of PHOTONS to advance the state-of-the-art by promoting co-operation between the partners through improved communication and networking of personnel.
The consortium's interests include optical nonlinearities in novel strained, piezo-electric, barrier-reservoir, coupled quantum well and Type II materials, the design, growth (by MBE and MOCVD), fabrication and charatcerisation of these novel materials and devices, the measurement of recombination lifetimes using photoluminesence and pump-probe techniques, the study of bistability and visible operation in VCSELs, the application of optical modulators and switches in optoelectronic systems and the optimisation of growth and fabrication techniques.
The activities of the group have to date consisted of two meetings of the partners. These meetings take the form of presentation and discussion sessions with the emphasis on information sharing and the identification of topical issues. The meetings are held at six monthly intervals and the location is rotated around the partners. Interested parties from outside the consortium attended the last meeting and this participation will be encouraged further throughout the course of the working group. The aims of the meetings are to facilitate information dissemination on research activities, collaboration and joint publications amongst the partners and to discover and discuss new approaches to the challenges in the various areas of interest.
Two meetings of the consortium have been held to date. At the first meeting in Dublin (November '92) each of the partners gave a summary of the issues they felt were relevant to their research aims and of interest to the Working Group. Three workshops identified the most critical issues and possible collaborations in the areas of materials and devices based on charge separation, VCSELs and strained materials, and fabrication and growth processes. After a further plenary session six topics were identified and various members of the group undertook to carry out detailed reviews in these areas and to report on these reviews at the second meeting which was held in Paris in June '93. These reviews were very useful in defining areas of mutual interest and issues that need to be addressed to advance the study and technology of QWMs.
Several informal collaboration have begun between the various members of the consortium. So far these collaborations have taken the form of the sharing of information, materials and expertise. Some resources are available for personnel exchange between members and this is to be encouraged in the future.
The short-term potential of the group has been achieved through the identification of the challenges in the various areas of interest in the study of QWMs. In the medium term the discussions and collaborations between the partners will lead to a better understanding of the physics and technology of QWMs. The improvements in the design, growth, fabrication and exploitation of QWM devices that will result from this work may allow the deployment of QWM devices in advanced optoelectronic systems.
Information exchange has been a core activity of the working group to date. The review process carried out in preparation for the second meeting of the group involved sharing, collating and contrasting results from the partners with experience in the relevant areas, namely Type II superlattices, asymmetric couple quantum wells and reservoir structures, VCSELs, strained materials and devices, etching and planarisation, contacting and addressing, and growth uniformity. Participants are kept up to date with the research activities of the working group and external interests through presentations at the plenary meetings.
Trinity College Dublin - IRL
Dept. of Pure and Applied Physics
IRL - DUBLIN 2
IMEC - B
Universität Duisburg - D
CNET - F
CNRS - L2M - F
University College Cork - IRL
Institute of Optical Research - S
University of Sheffield - UK
University College London - UK
Prof. J. Hegarty
PHOTONS - 7070, August 1994
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html version of synopsis by Nick Cook