Wavelength-selective switch for space-division multiplexed systems

Abstract

An optical apparatus includes a front optics section and a spectrometer section. The front optics section includes a spot de-multiplexer configured to receive a plurality of multi-mode optical signals each having a plurality of modal components, and to output in a linear array of a corresponding plurality of optical beams for each multimode optical signal. The spectrometer section includes a wavelength steering element configured to separate each of the optical beams into a plurality of wavelength channels. A fiber steering element is configured to steer the wavelength channels between the optical beams.

What is claimed is: 
     
         1 . An optical apparatus, comprising:
 a front optics section including a spot de-multiplexer configured to receive a plurality of multi-mode optical signals each having M modal components, and to output in a linear array M optical beams for each multimode optical signal;   a spectrometer section including:
 a wavelength steering element configured to separate each of said optical beams into a plurality of wavelength channels; and 
 a fiber steering element configured to steer said wavelength channels between said optical beams. 
   
     
     
         2 . The optical apparatus recited in  claim 1  wherein said spot demultiplexer includes a plurality of 3D waveguides, each waveguide of said plurality of waveguides corresponding to one of said modal components. 
     
     
         3 . The optical apparatus recited in  claim 2  wherein said front optics section further includes a plurality of collimators, each collimator being configured to collimate a corresponding one of the optical beams. 
     
     
         4 . The optical apparatus recited in  claim 1  further comprising a polarization mode de-multiplexer configured to separate polarization modes of said optical beams. 
     
     
         5 . The optical apparatus recited in  claim 1  wherein said wavelength steering element includes a diffraction grating configured to diffract said optical beams. 
     
     
         6 . The optical apparatus recited in  claim 1  wherein said spot-demultiplexer includes a photonic lantern configured to separate said multi-mode optical signals into said optical beams. 
     
     
         7 . The optical apparatus recited in  claim 1  wherein said linear array is arranged such that optical beams that correspond to modal components from same ones of said multi-mode optical signals are grouped together. 
     
     
         8 . A method of forming an optical apparatus, comprising:
 configuring a spot de-multiplexer to receive a plurality of multi-mode optical signals each having M modal components, and to output in a linear array of M optical beams for each multimode optical signal;   locating in a path of said optical beams a wavelength steering element configured to separate each of said optical beams into a plurality of wavelength channels; and   configuring a fiber steering element to steer said wavelength channels between said optical beams.   
     
     
         9 . The method recited in  claim 1  wherein said spot demultiplexer includes a plurality of 3D waveguides, each waveguide of said plurality of waveguides corresponding to one of said modal components. 
     
     
         10 . The method recited in  claim 2  further comprising configuring a plurality of collimators such that each collimator is located to collimate a corresponding one of the optical beams. 
     
     
         11 . The method recited in  claim 1  further comprising configuring a polarization mode de-multiplexer to separate polarization modes of said optical beams. 
     
     
         12 . The method recited in  claim 1  wherein said wavelength steering element includes a diffraction grating configured to diffract said optical beams. 
     
     
         13 . The method recited in  claim 1  wherein said spot-demultiplexer includes a photonic lantern configured to separate said multi-mode optical signals into said optical beams. 
     
     
         14 . The method recited in  claim 1  wherein said linear array is arranged such that optical beams that correspond to modal components from same ones of said multi-mode optical signals are grouped together. 
     
     
         15 . A wavelength-selective switch (WSS), comprising:
 a spot demultiplexer configured to receive from a plurality of optical fibers M multi-mode optical signals and form therefrom M*N optical beams, where N>1;   a diffraction element configured to separate said optical beams into wavelength-resolved optical beams; and   a steering element configured to direct a selected one of said wavelength-resolved optical beams from a first one of said optical fibers to a second one of said optical fibers.   
     
     
         16 . The WSS recited in  claim 15  wherein said spot-demultiplexer includes a three-dimensional waveguide corresponding to each of said optical beams. 
     
     
         17 . The WSS recited in  claim 15  wherein said spot-demultiplexer is further operable to arrange said optical beams a linear array in which optical beams corresponding to each multimode optical signal are grouped together. 
     
     
         18 . The WSS recited in  claim 15  wherein said steering element comprises a liquid-crystal on silicon (LCoS) device. 
     
     
         19 . The WSS recited in  claim 15  further comprising a polarization diversity element configured to separate polarization modes of said optical signals. 
     
     
         20 . The WSS recited in  claim 15  wherein said steering element is operable to receive a Fourier transform of said wavelength-resolved optical beams.