Accession Number : ADA236353


Title :   Optical Fibre Based Frequency Shifters Project


Descriptive Note : Final rept. 1 Jan 1989-31 Dec 1990,


Corporate Author : KENT UNIV CANTERBURY (UNITED KINGDOM) DEPT OF PHYSICS


Personal Author(s) : Berwick, M ; Jackson, D A


Full Text : http://www.dtic.mil/dtic/tr/fulltext/u2/a236353.pdf


Report Date : 28 Jan 1991


Pagination or Media Count : 80


Abstract : This report summarizes the research programme to develop acousto- optic frequency shifters based on highly linearly birefringent optical fibre. The theory of operation, fabrication and performance of devices utilizing either flexural or torsional acoustic waves is presented. Research directed towards a flexural acoustic wave fibre frequency shifter lead us to the conclusion that this technique is not suitable for the production of a high efficiency device. The research into torsional acoustic wave fibre frequency shifters has enabled the fabrication of devices with two different designs of torsional acoustic wave generator: (i) a side-fibre design and (ii) an in-line acoustic horn design. The fibre frequency shifters constructed from these generators produce a shift in the optical frequency of about 3MHz. A fibre frequency shifter constructed using the former design had a maximum optical power coupling efficiency of 6%; with an electrical power of 780mW applied to the transducer. Unfortunately, this design is rather fragile, hence a large proportion of research effort has been devoted to the design and fabrication of the more rugged in-line acoustic horns. The maximum optical power coupling efficiency achieved to date with this design of fibre frequency shifter is about 2.5%.


Descriptors :   *FREQUENCY , FIBERS , HIGH RATE , PRODUCTION , ACOUSTIC WAVES , THEORY , EFFICIENCY , FABRICATION , SHIFTING , OPERATION , BIREFRINGENCE , ELECTRIC POWER , TRANSDUCERS , RUGGEDIZED EQUIPMENT , FLEXURAL PROPERTIES , TORSION , ACOUSTOOPTICS , ACOUSTIC HORNS , SOUND GENERATORS , OPTICAL PROPERTIES


Subject Categories : Acoustooptic and Optoacoustic Devices
      Acoustics
      Optics


Distribution Statement : APPROVED FOR PUBLIC RELEASE