Abstract: A depolarizer for a broadband optical source to split the source beam by power, not by polarization state, and route the components into respective light paths. A polarization rotator arranged in one of the light paths rotates the polarization state of that beam component to make it orthogonal to that of the other. The components are then recombined by a combiner and output. A variable optical attenuator is arranged in one of the light paths, which during operation is adjusted by a controller to maintain power equalization between the light paths and hence depolarization performance. The controller receives power measurements from the light paths and from after the combiner via respective sensors. With this feedforward design reminiscent of a Mach-Zehnder interferometer the light from a light source which generates highly polarized light can be depolarized in theory with zero insertion loss and in practice with losses of about 1 dB.

Abstract: A depolarizer for a broadband optical source to split the source beam by power, not by polarization state, and route the components into respective light paths. A polarization rotator arranged in one of the light paths rotates the polarization state of that beam component to make it orthogonal to that of the other. The components are then recombined by a combiner and output. A variable optical attenuator is arranged in one of the light paths, which during operation is adjusted by a controller to maintain power equalization between the light paths and hence depolarization performance. The controller receives power measurements from the light paths and from after the combiner via respective sensors. With this feedforward design reminiscent of a Mach-Zehnder interferometer the light from a light source which generates highly polarized light can be depolarized in theory with zero insertion loss and in practice with losses of about 1 dB.

Abstract: A network element has at least one input, to which an optical signal can be fed, and at least one output, which is equipped to emit an optical signal; a first coupler having an input linked to the network element input and a first and a second output; an optical receiver having at least one input coupled to the second output of the first coupler and at least one output; an optical sender having at least one input of which is linked to the output of the optical receiver; a signal processing device being arranged in the signal path; a second coupler having a first input linked to the first output of the first coupler, a second input linked to the output of the optical sender, and an output which is linked to the first output of the network element.

Abstract: A network element has at least one input, to which an optical signal can be fed, and at least one output, which is equipped to emit an optical signal; a first coupler having an input linked to the network element input and a first and a second output; an optical receiver having at least one input coupled to the second output of the first coupler and at least one output; an optical sender having at least one input of which is linked to the output of the optical receiver; a signal processing device being arranged in the signal path; a second coupler having a first input linked to the first output of the first coupler, a second input linked to the output of the optical sender, and an output which is linked to the first output of the network element.

Abstract: An optical device having a semiconductor optical amplifier (SOA) coupled to an optical filter, which device may be used for optical performance monitoring. One embodiment of the invention provides an optical regenerator/monitor (RM), in which an SOA is used both for optical regeneration of a communication signal applied to the RM and for evaluation of the quality of that signal. The RM has (i) a 2R regenerator, which includes the SOA and an optical filter, and (ii) a relatively simple signal processor configured to receive optical signals from two or more sampling points located at the regenerator. In one configuration, the processor evaluates the quality of the communication signal by comparing optical power tapped from the input and output of the regenerator. The RM, so configured, can be used, for example, to monitor chromatic dispersion and/or optical noise in the communication signal.

Abstract: An optical device having a semiconductor optical amplifier (SOA) coupled to an optical filter, which device may be used for optical performance monitoring. One embodiment of the invention provides an optical regenerator/monitor (RM), in which an SOA is used both for optical regeneration of a communication signal applied to the RM and for evaluation of the quality of that signal. The RM has (i) a 2R regenerator, which includes the SOA and an optical filter, and (ii) a relatively simple signal processor configured to receive optical signals from two or more sampling points located at the regenerator. In one configuration, the processor evaluates the quality of the communication signal by comparing optical power tapped from the input and output of the regenerator. The RM, so configured, can be used, for example, to monitor chromatic dispersion and/or optical noise in the communication signal.