Alcatel

Alcatel Submarine Networks

Vincent Letellier

Olivier Gautheron

A drop/insert apparatus for dropping/inserting channels on a both-way multi-channel optical link includes a 'line' optical fiber serving to convey optical signals in two opposite transmission directions, over at least two channels having distinct wavelengths per transmission direction. The apparatus comprises: two main circulators inserted in said line fiber [two of the ports of each of them are connected to said line fiber, and their third ports are connected respectively to a first auxiliary optical fiber and to a second auxiliary optical fiber], each main circulator causing the optical signals to rotate in a rotation direction such that the signals propagating along said line fiber in one of the transmission directions remain in the line fiber; and, two auxiliary circulators inserted respectively in said first auxiliary fiber and in said second auxiliary fiber, each of said auxiliary circulators causing the optical signals to rotate in a direction opposite to that of the main circulator to which it is connected directly by one of said auxiliary fibers. At least one diffraction grating, having a reflection wavelength corresponding to the wavelength of a channel to be dropped in the go direction, is inserted in the line fiber between the main circulators, and at least one diffraction grating, having a reflection wavelength corresponding to the wavelength of a channel to be dropped in the return direction, is inserted in the by-pass fiber between the auxiliary circulators.

Drop/insert apparatus for dropping/inserting channels on a bidirectional

A process for locating a fault on an optical transmission link using a coherent detection reflectometer at a terminal sends over the transmission link measuring pulses and a loading signal interleaved between the measuring pulses. The loading signal is chosen to have the same optical wavelength as the measuring pulses with which it is combined and an extended bandwidth such that the power that it develops in the narrow measuring band of the reflectometer is negligible compared to that developed by the measuring pulses.

Process for locating by reflectometry a fault on an optical transmission

In an optical communication system using polarization scrambling of the transmitted optical signal, the scrambling causes the polarization vector to rotate. The scrambler includes a modulator to modulate either the phase or the wavelength of the optical signal. A polarization dispersion device converts the phase modulation or wavelength modulation into polarization modulation. This polarization dispersion device consists of the optical communication fibers on the output side of the modulator.

Growing community of inventors

Paris, France

Vincent Letellier