Patent ID: 8606106

Claim:
An optical fiber network comprising: a laser source configured to generate laser light of a plurality of wavelengths; at least one first optical fiber for transmitting multi-wavelength light from the laser source to a location remote from the laser source; a wavelength division multiplexer at the remote location and connected to a plurality of second optical fibers; a plurality of optical modulators each connected optically to the wavelength division multiplexer via a respective second optical fiber, wherein the wavelength division multiplexer is arranged to de-multiplex the multi-wavelength light received from the first optical fiber into a plurality of wavelengths and to supply a respective wavelength to each of the second optical fibers, the optical modulators are reflective optical modulators each arranged to modulate light received from the associated second optical fiber with a data signal and to reflect the modulated light back along the second optical fiber, the wavelength division multiplexer is arranged to multiplex the modulated light from all of the second optical fibers into a wavelength division multiplexed optical signal for onward transmission via a third optical fiber to a remote receiver, and the remote receiver comprises a calibration arrangement configured to apply an optical signal to an end of the third optical fiber remote from the wavelength division multiplexer and to measure a propagation delay between at least one of the optical modulators and the remote receiver by determining a time taken for the optical signal to be reflected by the optical modulator.