| CPC H04B 10/532 (2013.01) [G02F 1/0121 (2013.01); G02F 1/0136 (2013.01); H04B 10/11 (2013.01); H04B 10/118 (2013.01); H04B 10/50 (2013.01); H04B 10/516 (2013.01); H04B 10/548 (2013.01)] | 10 Claims |
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1. A modulator unit for modulating the phase of a polarization component of an optical signal, comprising:
a light source;
a polarizing beam splitter; and
a phase shifter;
wherein the light source is configured to output an optical signal and emit the output signal as an input signal in the direction of the polarizing beam splitter, wherein the optical signal contains a first polarization component having a first polarization direction and a second polarization component having a second polarization direction;
wherein the polarizing beam splitter is configured to split the input signal into the first polarization component and the second polarization component, to conduct the first polarization component via a first optical partial link in a first direction to the phase shifter, and to conduct the second polarization component via a second optical partial link in a second direction to the phase shifter, wherein the second direction is opposite to the first direction, so that the first polarization component and the second polarization component pass through the phase shifter in opposite directions;
wherein the first optical partial link or the second optical partial link contains a polarization rotator, configured to change a polarization direction of optical signals that pass the polarization rotator such that the first polarization component has the same polarization direction as the second polarization component when the first polarization component and the second polarization component are incident on the phase shifter;
wherein the phase shifter includes a first Faraday rotator, a second Faraday rotator, and a polarization-dependent phase modulator;
wherein the polarization-dependent phase modulator is arranged along an optical path through the phase shifter between the first Faraday rotator and the second Faraday rotator;
wherein the first optical partial link is optically coupled to the first Faraday rotator and the second optical partial link is optically coupled to the second Faraday rotator;
wherein the first Faraday rotator is configured to change a polarization direction of passing optical signals in a first polarization change direction;
wherein the second Faraday rotator is configured to change a polarization direction of passing optical signals in a second polarization change direction;
wherein the second polarization change direction is different from the first polarization change direction, so that the first polarization component and the second polarization component, when they pass the polarization-dependent phase modulator, are polarized in polarization directions perpendicular to one another;
wherein the polarization-dependent phase modulator is configured to execute a phase modulation of only one polarization component; and
wherein the polarizing beam splitter is arranged to receive the first polarization component via the second optical partial link and to receive the second polarization component via the first optical partial link, and to combine the first polarization component and the second polarization component to form a superimposed optical signal.
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