Bandwidth-distance Product | previous | next | feedback |
Definition: product of length and maximum data rate of a fiber-optic link
The term bandwidth-distance product is often used in the context of optical fiber communications. It is usually defined as the product of the length of a fiber-optic link and its maximum data rate (in Gbit/s) (i.e., not its optical bandwidth). That product is typically limited by the acceptable bit error rate.
The concept of the bandwidth-distance product is helpful e.g. for comparing the relative merits of different types of fiber-optic links. However, the definition by no means implies that the achievable bandwidth-distance product is independent of the chosen fiber length. Whether this is the case, depends on the circumstances. It can be true for a link based on multimode fiber, the capacity of which is limited by intermodal dispersion. On the other hand, in a link based on single-mode fiber, which is limited by chromatic dispersion and which does not contain means for dispersion compensation, a doubling of the data rate may enforce a reduction in the fiber length by a factor of four. The bandwidth-distance product is then effectively reduced by a factor of two. However, the transmission distance may of course also be doubled by concatenating two fiber-optic links with electronic regeneration between them.
See also: bandwidth, optical fiber communications, fiber-optic links, bit error rate
Categories: communications, fibers and other waveguides
