Orthogonally-combining interleaving filter multiplexer and systems and methods using same

An optical communication system comprising:

• a transmitting terminal configured to transmit a wavelength division multiplexed (WDM) signal on a plurality of optical channels including a first set of channels and a second set of channels, the transmitting terminal comprising an orthogonally-combining interleaving filter multiplexer configured to receive a first set of channel wavelengths on a first optical fiber and to polarize said first set of channel wavelengths with a first polarization and provide the first set of multiplexed channel wavelengths along a first optical input path extending along a first axis, and to receive a second set of channel wavelengths on a second optical fiber different from said first optical fiber and to polarize said second set of channel wavelengths with a second polarization and provide the second set of multiplexed channel wavelengths along a second optical input path extending along a second axis, the second optical input path being generally perpendicular to the first optical input path, the first and second polarizations being substantially orthogonal to each other, the orthogonally-combining interleaving filter multiplexer comprising interleaver optics comprising:
• a beam combiner disposed along the first optical input path and the second optical input path and configured to pass the first set of multiplexed channel wavelengths and reflect the second set of multiplexed wavelengths;
• a reflector disposed along the first optical input path and configured to receive the first set of multiplexed channel wavelengths passed by the beam combiner, the reflector being angled at a first angle relative to the first optical input path such that the reflector is configured to reflect the received first set of multiplexed channel wavelengths along an optical output path extending along a third axis;
• a Gires-Tournois (GT) cavity established between the beam combiner and the reflector,
• wherein the interleaver optics are configured to simultaneously pre-filter and combine the first set of channel wavelengths with the first polarization and the second set of channel wavelengths with the second polarization to produce a pre-filtered, pair-wise orthogonal WDM aggregate optical signal along the optical output path;
• and
• a combined channel optical output comprising an output fiber disposed along the optical output path and configured to receive and output the pre-filtered, pair-wise orthogonal aggregate optical signal;
• a receiving terminal optically coupled to the combined channel optical output and configured to receive the pre-filtered, pair-wise orthogonal WDM aggregate optical signal on the plurality of optical channels and configured to separate the WDM aggregate optical signal into separate optical signals at the channel wavelengths;
• and
• an optical transmission path coupling the transmitting terminal and the receiving terminal.

Line terminating equipment comprising:

• a plurality of odd channel transponders configured to transmit and receive optical signals modulated on odd channel wavelengths;
• a plurality of even channel transponders configured to transmit and receive optical signals modulated on even channel wavelengths;
• at least one odd channel wavelength multiplexer configured to combine the optical signals modulated on the odd channel wavelengths after the odd channel transponders to produce an aggregate odd channel optical signal;
• at least one odd channel wavelength demultiplexer configured to separate the optical signals modulated on the odd channel wavelengths before the odd channel transponders;
• at least one even channel wavelength multiplexer configured to combine the optical signals modulated on the even channel wavelengths after the even channel transponders to produce an aggregate even channel optical signal;
• at least one even channel wavelength demultiplexer configured to separate the optical signals modulated on the even channel wavelengths before the even channel transponders;
• and
• an orthogonally-combining interleaving filter multiplexer configured to receive the aggregate odd channel optical signal on a first optical fiber and to polarize the aggregate odd channel optical signal with a first polarization and provide the aggregate odd channel optical signal along a first optical input path extending along a first axis, and to receive the aggregate even channel optical signal on a second optical fiber different from said first optical fiber and to polarize the aggregate even channel optical signal with a second polarization and provide the aggregate even channel optical signal along a second optical input path extending along a second axis, the second optical input path being generally perpendicular to the first optical input path, the second polarization being substantially orthogonal to the first polarization, the orthogonally-combining interleaving filter multiplexer comprising interleaver optics comprising:
• a beam combiner disposed along the first optical input path and the second optical input path and configured to pass the aggregate odd channel optical signal or the aggregate even channel optical signal and reflect the other of the aggregate odd channel optical signal or the aggregate even channel optical signal;
• a reflector disposed along the first optical input path and configured to receive an optical signal passed by the beam combiner, the reflector being angled at a first angle relative to the first optical input path such that the reflector is configured to reflect the received optical signal along an optical output path extending along a third axis;
• a Gires-Tournois (GT) cavity established between a beam combiner and a reflector,
• wherein the interleaver optics are configured to simultaneously pre-filter and combine the aggregate odd channel optical signal with the first polarization and the aggregate even channel optical signal with the second polarization to produce a pre-filtered, pair-wise orthogonal aggregate optical signal along the optical output path;
• a combined channel optical output comprising an output fiber disposed along the optical output path and configured to receive and output the pre-filtered, pair-wise orthogonal optical signal.

An optical transmission method comprising:

• modulating a plurality of data streams on a first set of channel wavelengths and on a second set of channel wavelengths, respectively, to produce optical signals on respective first and second sets of channels;
• combining the optical signals on the first set of channels onto a single PM optical path;
• combining the optical signals on the second set of channels onto a single PM optical path;
• providing the combined optical signals on the first set of channels on a first optical fiber in an orthogonally-combining interleaving fiber multiplexer;
• providing the combined optical signals on the second set of channels on a second optical fiber different from the first optical fiber in the orthogonally-combining interleaving fiber multiplexer;
• providing the combined optical signals on the first set of channels with a first polarization in the orthogonally-combining interleaving filter multiplexer;
• providing the combined optical signals on the second set of channels with a second polarization substantially orthogonal to the first polarization in the orthogonally-combining interleaving filter multiplexer;
• and
• simultaneously pre-filtering and combining the optical signals with the first polarization and the optical signals with the second polarization using interleaver optics comprising:
• a first optical fiber configured to provide an optical signal with the first polarization along a first optical input path extending along a first axis;
• a second optical fiber configured to provide an optical signal with the second polarization along a second optical input path extending along a second axis;
• a beam combiner disposed along the first optical input path and the second optical input path and configured to pass the optical signal with the first polarization or the optical signal with the second polarization, and reflect the other of the optical signal with the first polarization or the optical signal with the second polarization;
• a reflector disposed along the first optical input path and configured to receive an optical signal passed by the beam combiner, the reflector being angled at a first angle relative to the first optical input path such that the reflector is configured to reflect the received optical signal along an optical output path extending along a third axis;
• a Gires-Tournois (GT) cavity established between a beam combiner and a reflector in the orthogonally-combining interleaving filter multiplexer to produce a pre-filtered, pair-wise orthogonal aggregate optical signal along the optical output path;
• and
• a combined channel optical output comprising an output fiber disposed along the optical output path and configured to receive and output the pre-filtered, pair-wise orthogonal optical signal.