A multi-function optical tool may be used for example for built-in fault detection and transceiver source characterization in local optical communication networks. A single device provides swept-heterodyne optical spectrum analysis (SHOSA) and optical frequency-domain reflectometry (OFDR) in an efficient, low-cost package by utilizing a common interrogation laser source, common optical components, and common, low-bandwidth acquisition hardware. The technology provides significant cost, space, and labor savings for network maintainers and technicians.