Abstract

Passive optical networks (PONs) have been proposed as subscriber-loop distribution systems because they require no power or processing between the central office (CO) and the optical-network units (ONUs).¹ PONs have not been universally accepted, however. Conventional PONs, although inexpensive, have restricted service upgrades.² Wavelength-division-multiplexed (WDM) PONs provide tremendous upgrade potential but are considered to be too expensive.¹ We recently reported a PON (RITE-Net) that uses a waveguide-grating router³ (WGR) to share a single tunable distributed-Bragg-reflector (DBR) laser between the CO and all ONUs and adds significant operational advantages by looping back and overmodulating a portion of the downstream light with upstream data.⁴

© 1995 Optical Society of America