System, apparatus, and architecture for migrating an optical communication network
AssigneeGoogle Inc.
InventorsXiang Zhou, Cedric F. Lam, Ryohei Urata, Hong Liu
Life of this patent
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Abstract
Coherent optical communications technology for recovery of 1D and 2D formatted optical signals. For example, 1D or 2D formatted signals that travel through fiber optic media may be recovered by separating the light into X- and Y-polarization components, rotating one polarization component (e.g., Y-component) into the polarization space of the other component (e.g., Y-component into the X-polarization space), delaying the rotated component enough to avoid destructive interference and combining the delayed component with the undelayed component to form a folded optical signal, which may then be processed as a X-polarized signal.
Claims19
An optical transmission system comprising:
- a transmitter, the transmitter configured to generate a four-dimensional signal, the transmitter comprising:
- a laser;
- a first Mach Zehnder modulator optically coupled to the laser;
- a second Mach Zehnder modulator optically coupled to the laser;
- a first multiplexer optically coupled directly to the first Mach Zehnder modulator;
- a second multiplexer;
- a time delay module optically coupling the second Mach Zehnder modulator and the second multiplexer;
- and
- a polarization beam combiner coupled to the first and second multiplexers and configured to output an encoded signal received from the first and second multiplexers onto an optical fiber;
- and
- a receiver, the receiver comprising:
- a polarization beam splitter configured to receive the encoded signal;
- at least one of an optical coupler or a Mach-Zehnder interferometer optically coupled to the polarization beam splitter;
- a de-multiplexer optically coupled to the at least one of the optical coupler or the Mach-Zehnder interferometer to receive an optical signal comprising the encoded signal;
- and
- a 90 degree hybrid coupled to a local oscillator signal generated at the transmitter and configured to receive a folded optical signal from the de-multiplexer,
- wherein the receiver is a two-dimensional coherent receiver configured to receive the folded optical signal.
An optical transmission system comprising:
- a transmitter, the transmitter configured to generate a four-dimensional signal, the transmitter comprising:
- a laser;
- first Mach Zehnder modulator optically coupled to the laser;
- a second Mach Zehnder modulator optically coupled to the laser;
- a first multiplexer optically coupled directly to the first Mach Zehnder modulator;
- a second multiplexer;
- a polarization beam combiner configured to output a signal to a receiver;
- a phase shifter optically coupled to the second Mach Zehnder modulator;
- and
- a time delay module optically coupled to the second multiplexer and the phase shifter;
- and
- a two-dimensional coherent receiver, the receiver comprising:
- a polarization beam splitter;
- at least one of an optical coupler or a Mach-Zehnder interferometer optically coupled to the polarization beam splitter;
- a de-multiplexer optically coupled to the at least one optical coupler or Mach-Zehnder interferometer;
- and
- a 90 degree hybrid coupled to a local oscillator signal generated at the transmitter and configured to receive a folded optical signal from the de-multiplexer.
Dependencies are inferred from the claim text.