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The existing far infrared spectroscopy beam line at the Daresbury Laboratory Synchrotron Radiation Source (SRS) has been adapted to provide intense collimated radiation for a mid infrared microscope. The SRS beam is focused by the microscope onto an area of the sample only 20 X 30 microns in size and this allows the collection of high fidelity data from samples smaller than 10 microns across. At these dimensions, signal-to-noise is significantly greater than with a conventional infrared source. This new facility is now finding applications with a wide range of users in areas such as materials science, conservation, and biomedicine. As part of a collaboration between Daresbury Laboratory, Nottingham University and University Hospital, Nottingham, the instrument is being applied to investigate the subtle chemical differences which occur between normal and cancerous cells on a cell-by-cell basis. Significant spectral shifts, some of which have previously only been observed in macroscopic samples, can be identified in single cells. The enhanced ability to make such measurements by using synchrotron radiation as the IR source has potential to provide a clearer understanding of the changes occurring in cancerous and pre-cancerous cells.

This paper describes how an experimental full services access network has been constructed at BT Labs and presents views on how its performance could be improved to meet the reliability and traffic loading requirements expected in real applications such as fiber to the business and fiber to the cabinet. The experimental network included: asynchronous transfer mode (ATM) switch, an ATM passive optical network (PON), very high speed digital subscriber loop (VDSL) customer drop and ATM forum 25 Mbit/s customer network. The design and realization of the VDSL customer drop, the signaling system and the interfaces between the system elements formed a major part of the design and construction work at BT Labs. The ability to cope with varying service demand and achieving the necessary quality of service are important requirements for roll-out systems. This paper describes how these requirements could be met in the design of future proprietary equipment.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.