Cost-Technology Tradeoffs in Multifiber Wavelength Division Networks

The terahertz bandwidth available in an optical fiber offers unprecedented opportunities for high speed network implementations. The efficient use of this enormous bandwidth in distributed communications networks, however, poses several novel challenges. These challenges can be overcome in part with the design of new, more powerful photonic devices, and in part with the development of novel protocols and systems architectures. For example, the requirement to switch short data blocks on a multiaccess, single hop, wavelength division optical channel can be satisfied by using extremely fast tunable lasers/filters (subnanosecond tuning time), which are still in the experimental stage. Alternatively, the same requirement can be met by using slower devices (microsecond tuning time) and by adopting novel channel access methodologies (e.g. transmitter pipelining and subframe tuning) and network architectures (e.g. multihopping). This talk will examine some of the system design alternatives that can be used to over-come the optical network bottlenecks. These alternatives will include pipelining, mutihopping and multifiber layouts. The tradeoffs between the use of advanced (costly) photonic technology and the implementation of novel system strategies will be addressed. These design tradeoffs will be illustrated with an example based on OPTIMIC, an optical network architecture that combines new network models and advanced device technologies. OPTIMIC ( OPTical Interconnect of MosaIC chips) is a high speed local and campus network for the interconnection of supercomputers and high speed peripherals, currently under development by UCLA, JPL and Aerospace under ARPA support.