Ž . Optical Fiber Technology 5, 165174 1999 Article ID ofte.1998.0290, available online at http:www.idealibrary.com on Dispersion Effects in Millimeter-Wave Fiber-Radio Systems Employing Direct-Sequence Code Division Multiple Access G. H. Smith, A. Nirmalathas, J. Yates,* and D. Novak Australian Photonics Cooperati  e Research Centre, Photonics Research Laboratory, Department of Electrical and Electronic Engineering, Uni  ersity of Melbourne, Park  ille, Victoria 3052, Australia; and *Software Engineering Research Centre, RMIT Uni  ersity, 723 Swanston Street, Carlton, Victoria 3053, Australia E-mail: grsm@ee.mu.oz.au Received August 17, 1998; revised October 29, 1998 We investigate the impact of fiber chromatic dispersion on the perfor- mance of an externally modulated millimeter-wave fiber-radio system incor- porating a broadband radio direct-sequence code division multiple access Ž . DS-CDMA scheme. In particular, we investigate the effect of dispersion on DS-CDMA signals with regard to CDMA code rate, center frequency, and modulator chirp. We show that the spreading of the signal spectrum using DS-CDMA can result in significant reductions in data amplitude variations normally experienced in externally modulated millimeter-wave fiber-radio systems. We also demonstrate the successful transmission of a 10-Mbs data channel over a 39-GHz fiber-radio link employing DS-CDMA and consisting of 25 km of standard optical fiber and a 1-m radio link.  1999 Academic Press 1. INTRODUCTION A promising technology for the provision of future broadband interactive multi- media services in local access and mobile applications is via a network of millime- Ž . ter-wave mm-wave radio systems operating at frequencies such as 28, 42, and 60   GHz 1, 2 . The large propagation losses at these frequencies, however, significantly Ž . reduce the radio coverage area per antenna base station BS , so that a large number of BSs may be required. The development of simple, low-cost antenna BSs is therefore essential for the implementation of mm-wave radio networks. The use Ž . of optical fiber for the distribution of the radio signals from a central office CO 165 1068-520099 $30.00 Copyright  1999 by Academic Press All rights of reproduction in any form reserved.