A Cryogenic Optical Fiber Irradiation System
Abstract
This paper examines the feasibility of using a cryogenic optical fiber link for an irradiation study of the quantum Hall effect (QHE). Commercially available GaAs₁₋ₓPₓ light-emitting diodes (LED's) were studied at temperatures between 4.2 and 300 K to examine their suitability for use in a cryogenic environment. Results for light output versus current and temperature, including freeze-out temperatures, are presented along with I-V characteristics at 4.2, 77, and 300 K. A surprising form of negative resistance is observed in infrared GaAs arid yellow GaAs₀.₈₅P.₁₅ LED's at low temperatures. Further, an attempt to measure optical fiber attenuation as a function of temperature showed that for fiber lengths under 5 m the changes were smaller than the resolution of the experiment. The optical link as a whole provided light powers between 6X10⁻⁷ and 1X10⁻⁵ milliwatts, adequate to extend a previous QHE study.
Description
Program year: 1996/1997Digitized from print original stored in HDR
Citation
Prater, Craig B. (1987). A Cryogenic Optical Fiber Irradiation System. University Undergraduate Fellow. Available electronically from https : / /hdl .handle .net /1969 .1 /CAPSTONE -PraterC _1987.