Technical Insight
Optical Internetworking Forum Debuts VSR Specifications (Fiber Optics News)
The Optical Internetworking Forum, a non-profit group of 300 companies that promotes worldwide compatibility of optical internetworking products, has adopted two 10 Gb/s (OC-192) Very Short Reach (VSR) interface agreements. The two VSR standards are complementary and intended to help reduce the cost of OC-192/STM-64 links between equipment in a single central office. VSR-1 is based on parallel optics and features twelve 850 nm lasers each operating at 1.25 Gb/s, such as used in commercially-available VCSEL arrays. Designed for distances up to 300 m, VSR-1 recommends the use of 62.5 m-core multi-mode ribbon fiber and is potentially the lowest cost OC-192 link. VSR-2 is a 1310 nm serial interface utilizing installed single-mode fiber over distances up to 600 m, which enables links within very large central offices. Compared to SONET Short Reach interfaces, this standard tolerates increased dispersion and reduced reach to enable cheaper devices to be used. "Using existing interfaces designed for longer distances results in unnecessary cost," said Russ Tuck, chairman of Physical and Link Layer Working Group at OIF. "Carriers and network service providers can save thousands of dollars per interface by using OIF VSR interfaces to link co-located equipment."
