For the quality of service (QoS) and fairness considerations, the hop counts of various lightpaths in a wavelength division multiplexing (WDM) optical network should be short and compact. The development of multi-granularity optical switching technology has made it possible to construct various fiber topologies over a fixed physical topology. This paper describes a fiber topology design (FTD) problem, which minimizes the maximum number of required fibers in the physical links for a maximum lightpath hop count in the fiber topology. After the formular description for the FTD problem, a method was given to obtain the lower bound on the maximum number of required fibers. For large or moderate scale networks, three heuristic algorithms are given to efficiently solve the FTD problem. This study gives a new way to optimize the resource configu- ration performance in WDM optical networks at the topology level and proves its effectiveness via both analyses and numerical experiments. For the quality of service (QoS) and fairness considerations, the hop counts of various lightpaths in a wavelength division multiplexing (WDM) optical network should be short and compact. The development of multi-granularity optical switching technology has made it possible to construct various fiber topologies over a fixed physical topology. This paper describes a fiber topology design (FTD) problem, which minimizes the maximum number of required fibers in the physical links for a maximum lightpath hop count in the fiber topology. After the formular description for the FTD problem, a method was given to obtain the lower bound on the maximum number of required fibers. For large or moderate scale networks, three heuristic algorithms are given tofficient solve the FTD problem. This study gives a new way to optimize the resource configu- ration performance in WDM optical networks at the topology level and proves its effectiveness via both analyzes and numerical experiments.