Optical multi-wavelength dual-polarization transceivers

1 . A multi-wavelength dual-polarization (DP) receiver comprising:

an input port configured to receive input light;

an optical polarization splitter and rotator configured to split the input light into a first optical waveguide and a second optical waveguide;

a first wavelength demultiplexer connected to the first optical waveguide and configured to output wavelength-demultiplexed light into a first plurality of optical waveguides;

a second wavelength demultiplexer connected to the second optical waveguide and configured to output wavelength-demultiplexed light into a second plurality of optical waveguides;

a plurality of optical multi-input-multi-output (MIMO) polarization demultiplexers, each of which is connected to a respective one of the first plurality of optical waveguides and one of the second plurality of optical waveguides; and

circuitry configured to detect, from a first output and a second output of each of the plurality of MIMO polarization demultiplexers, a first modulated signal and a second modulated signal, respectively.

2 . The multi-wavelength DP receiver of claim 1 , further comprising at least one variable optical attenuator (VOA) connected to at least one output of at least one of the first wavelength demultiplexer or the second wavelength demultiplexer, wherein the at least one VOA is configured to equalize a loss between light provided through the first optical waveguide and light provided through the second optical waveguide.

3 . The multi-wavelength DP receiver of claim 1 , wherein the optical polarization splitter and rotator, the first and second wavelength demultiplexers, and the plurality of optical MIMO polarization demultiplexers are all implemented on the same chip.

4 . The multi-wavelength DP receiver of claim 3 , wherein the chip has a silicon substrate.

5 . The multi-wavelength DP receiver of claim 3 , further comprising a transimpedance amplifier that is integrated into the chip.

6 . The multi-wavelength DP receiver of claim 3 , wherein electronic control for the plurality of optical MIMO polarization demultiplexers is integrated into the chip.

7 . The multi-wavelength DP receiver of claim 3 , further comprising a Stokes measurement apparatus that is integrated on the same chip.

8 . The multi-wavelength DP receiver of claim 1 , wherein the first wavelength demultiplexer and the second wavelength demultiplexer are each configured to output demultiplexed light having a plurality of wavelengths into the first plurality of optical waveguides and the second plurality of optical waveguides, respectively, and

wherein, for each wavelength of the plurality of wavelengths, a path length from the first wavelength demultiplexer to a first input input of a MIMO polarization demultiplexer, of the plurality of optical MIMO polarization demultiplexers, that receives light having the wavelength is within 0.2 mm of a path length from the second wavelength demultiplexer to a second input of the MIMO polarization demultiplexer.

9 . The multi-wavelength DP receiver of claim 1 , wherein the multi-wavelength DP receiver is co-packaged with a digital-signal processor.

10 . The multi-wavelength DP receiver of claim 1 , further comprising taps and monitor photodiodes that are implemented on outputs of at least one of the plurality of optical MIMO polarization demultiplexers.

11 . The multi-wavelength DP receiver of claim 1 , wherein the first and second wavelength demultiplexers have wavelengths that are electronically adjustable.

12 . The multi-wavelength DP receiver of claim 1 , wherein the first wavelength demultiplexer outputs a first plurality of wavelength-demultiplexed light signals of N wavelengths into the first plurality of optical waveguides,

wherein the second wavelength demultiplexer outputs a second plurality of wavelength-demultiplexed light signals of the N wavelengths into the second plurality of optical waveguides, and

wherein an ordering of the N wavelengths for the first plurality of wavelength-demultiplexed light signals that are output from the first wavelength demultiplexer and an ordering of the N wavelengths for the second plurality of wavelength-demultiplexed light signals that are output from the second wavelength demultiplexer are in an opposite order.

13 . The multi-wavelength DP receiver of claim 12 , wherein at least one of the N wavelengths has no waveguide crossings among the first plurality of optical waveguides and the second plurality of optical waveguides between the first and second wavelength demultiplexers and the plurality of MIMO polarization demultiplexers.

14 . The multi-wavelength DP receiver of claim 1 , wherein the circuitry comprises a plurality of photodetectors connected to respective outputs of the plurality of optical MIMO polarization demultiplexers.