Abstract
The most effective way of increasing the transmission capacity of an optical fibre communication system is to use the extremely wide bandwidth of an optical fibre and to feed a large number of channels as is practicable into the fibre. However, a major obstacle to the development of ultra-wide-band dense wavelength division multiplexing systems is the nonlinear optical effects in the fibre that can distort the pulses and produce significant crosstalk among the wavelength channels. A direct way to suppress such nonlinear effect is to use a fibre with a large effective core area. A novel design of the optical fiber is invented in which a core is surrounded by a cladding having a refractive index that varies periodically in the angular sense around the core. By appropriate design of the cladding, it is possible to provide an optical fiber capable of single-mode operation over a wide range of wavelengths with a large effective area for ultra-high capacity transmission.

Applications
The novel fibre design can be applied to ultra wideband telecommunications, allowing enhanced broadband Internet data transfer as well as improved long-distance telecommunications and TV signal transmissions. The development could help to lower the cost of ultra wideband telecommunications internationally.

Contact Information
Mr H Y Wong
Director, Technology Transfer Office
City University of Hong Kong
83 Tat Chee Avenue
Kowloon, Hong Kong
Tel : (852) 2788 8428
Fax : (852) 2788 9119
Email : hy.wong@cityu.edu.hk