EPSRC logo

Details of Grant 

EPSRC Reference: GR/J50149/01
Principal Investigator: Sarma, Dr J
Other Investigators:
Robson, Professor P Shore, Professor A
Researcher Co-Investigators:
Project Partners:
Department: Electronic and Electrical Engineering
Organisation: University of Bath
Scheme: Standard Research (Pre-FEC)
Starts: 01 February 1994 Ends: 31 January 1997 Value (£): 114,723
EPSRC Research Topic Classifications:
Materials Characterisation Optoelect. Devices & Circuits
EPSRC Industrial Sector Classifications:
Related Grants:
Panel History:  
Summary on Grant Application Form
1) To develop self consistent models of VCSELs including carrier distribution and transverse and longitudinal modal field profiles.2) VCSEL fabrication and mode profile measurements.Progress:The initial effort of the project has been directed at developing a full treatment of the (resonator) modes of weakly index-guided cylindrical VCSELs with the object of calculating modal gains. The thesis being pursued in this project is that modal gain is one of the dominant properties that determine the operational characteristics of VCSELs. For this purpose an efficient procedure for calculating the carrier distribution in the device has been constructed. The calculation method has been extended to enable two-dimensional (radial and azimuthal) carrier distributions to be obtained. The computational procedure has evolved further so that now the carrier distribution is obtained consistently with the (modal) optical intensity distributions and lasing conditions can be modelled. This part of the project is complete and a computer programme is now available for indicating the effects of modal gain competition that can be expected to determine VCSEL characteristics. On this basis the second stage of the project will be directed at mode selection techniques, in particular at examining concepts for tailoring current injection to preferentially excite specified VCSEL (resonator) modes. Complementary effort is being given to developing a model of the dynamical evolution of the transverse modes in VCSELs. The modelling techniques are simultaneously being extended to incorporate gain-guided structures and the influence of temperature variations. Future activities will centre on implementing computer codes incorporating the physical features indicated above. In collaboration with Sheffield University it is planned to undertake device fabrication and discussion is currently under way on the design of suitable structures. In this aspect of the work it is aimed to make a comparison between experimentally measured and theoretically predicted mode profiles.
Key Findings
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
Potential use in non-academic contexts
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
Description This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
Date Materialised
Sectors submitted by the Researcher
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
Project URL:  
Further Information:  
Organisation Website: http://www.bath.ac.uk