Patent ID: 8655166

Claim:
A method of performing optical measurements of an optical fiber from a network terminal for an optical fiber network, the optical fiber network disposed to having one or more optical fibers to couple to network terminal, the network terminal disposed to having an optical transceiver for coupling to the optical fibers, and the optical transceiver disposed to having a first optical receiver for receiving optical data signals on a first wavelength and the optical transceiver disposed to having an optical transmitter for transmitting optical signals on a second wavelength and the optical transceiver disposed to having a second optical receiver for receiving optical signals on the second wavelength, and the network terminal having a controller coupled to the optical transceiver and for communicating using a network protocol having predetermined time intervals or frames for data communications with other network terminals, the method of performing optical measurements of the optical fiber using the second wavelength comprising the steps of: (a) scheduling by the controller a test interval of predetermined time in synchrony with the predetermined time intervals or frames of the network protocol, the test interval comprising a first time interval for transmitting an optical test signal followed by a second time interval for turning off the optical transmitter followed by a third time interval for measuring the optical test signal; (b) during the first time interval of the test interval, transmitting the optical test signal on the second wavelength by the optical transmitter onto an optical fiber; (c) during the second time interval of the test interval, turning off the optical transmitter resulting in no further light transmissions on the optical fiber; (d) during the third time interval of the test interval, measuring a portion of the optical test signal on the second wavelength by the second optical receiver; and (e) turning on the optical transmitter after the test interval and transmitting optical data signals for communicating to another network terminal, whereby the network terminal is disposed to perform optical measurements while the network terminal is in-service and the continuity of data communications is maintained by scheduling, transmitting and measuring the optical test signal in accordance and in synchrony with predetermined time intervals or frames of the network protocol.