Reconfigurable optical switch

Abstract

An optical switch is provided which includes a plurality of input/output ports for receiving one or more wavelength component(s) of an optical signal. The optical switch also includes an optical arrangement that directs the wavelength component to any given one of the plurality of input/output ports. The given input/output port may be selected from among any of the plurality of input/output ports. If the optical signal includes a plurality of wavelength components, the optical arrangement includes at least one wavelength selective element such as a thin film filter. The wavelength selective element selects one of the wavelength components from among the plurality of wavelength components. The optical arrangement also includes a plurality of optical elements each associated with one of the wavelength selective elements. Each of the optical elements direct the selected wavelength component, which is selected by its associated selective element, to a given one of the plurality of input/output ports independently of every other wavelength component. The optical elements may be tiltable retroreflective mirror assemblies.

1 . An optical switch comprising:
 a plurality of input/output ports for receiving at least first and second wavelength components of a WDM optical signal;   a demultiplexer arrangement for sequentially demultiplexing the first and second wavelength components from the WDM optical signal;   an optical arrangement for directing, prior to demultiplexing the second wavelength component, the first wavelength component from a first of the input/output ports to any selected ones of the plurality of input/output ports which includes the first input/output port such that any one of the input/output ports can serve as an input port and an output port for the first wavelength component.   
   
   
       2 . The optical switch of  claim 1  further comprising a free space region disposed along an optical path traversed by the first wavelength component between the input port and the output port. 
   
   
       3 . The optical switch of  claim 2  wherein said optical arrangement includes thin film filters each transmitting therethrough a different one of the wavelength components of the WDM optical signal and reflecting remaining wavelength components. 
   
   
       4 . The optical switch of  claim 1  wherein said demultiplexing arrangement includes a plurality of wavelength selective elements selecting one of the wavelength components from the WDM optical signal and said optical arrangement includes a plurality of optical elements each associated with one of the wavelength selective elements. 
   
   
       5 . The optical switch of  claim 4  wherein said optical elements are reflective mirrors that are selectively tiltable in a plurality of positions such that in each of the positions the mirrors reflect the wavelength component incident thereon to any selected one of the input/output ports. 
   
   
       6 . The optical switch of  claim 5  wherein said reflective mirrors are part of a micro-electromechanical (MEM) retroreflective mirror assembly. 
   
   
       7 . The optical switch of  claim 6  wherein said retroreflective mirror assembly includes an aspheric lens. 
   
   
       8 . The optical switch of  claim 6  wherein said retroreflective mirror assembly includes a curved reflector element. 
   
   
       9 . The optical switch of  claim 5  wherein said reflective mirrors each include a piezoelectric actuator. 
   
   
       10 . The optical switch of  claim 3  wherein the free space region includes an optically transparent substrate and the thin film filters are disposed on the optically transparent substrate. 
   
   
       11 . The optical switch of  claim 10  wherein said demultiplexing arrangement includes a plurality of wavelength selective elements selecting one of the wavelength components from the WDM optical signal, said plurality of wavelength selective elements being arranged in first and second arrays respectively extending along first and second surfaces of the optically transparent substrate. 
   
   
       12 . The optical switch of  claim 11  wherein the first and second surfaces are parallel to one another. 
   
   
       13 . The optical switch of  claim 12  wherein said first and second arrays are laterally offset with respect to one another. 
   
   
       14 . The optical switch of  claim 13  wherein each of said wavelength selective elements arranged in the first array direct the selected wavelength component to another of said wavelength selective elements arranged in the second array. 
   
   
       15 . The optical switch of  claim 4  wherein the plurality of wavelength selective elements are arranged in a closed configuration. 
   
   
       16 . The optical switch of  claim 15  wherein said closed configuration is a circular configuration. 
   
   
       17 . The optical switch of  claim 14  further comprising a focusing mirror arranged in the first array, said focusing mirror reducing insertion loss by adjusting a beam waist location of the optical signal. 
   
   
       18 . The optical switch of  claim 2  wherein the free space region includes ambient air. 
   
   
       19 . The optical switch of  claim 2  wherein the free space region includes silica glass. 
   
   
       20 . The optical switch of  claim 4  further comprising a collimating lens disposed between each one of said wavelength selective elements and the optical element associated therewith, each of said optical elements being positioned at a focal point of the lens associated therewith. 
   
   
       21 . The optical switch of  claim 20  wherein said collimating lens and said optical element serve as a retroreflector. 
   
   
       22 . The optical switch of  claim 1  wherein said optical arrangement includes at least one collimating lens and at least one tiltable mirror. 
   
   
       23 . An optical switch comprising:
 a plurality of input/output ports for receiving at least first and second wavelength components of a WDM optical signal;   a first wavelength selective element for demultiplexing the first wavelength component from the WDM optical signal;   a first optical element for directing the first wavelength component from a first of the input/output ports to any selected ones of the plurality of input/output ports which includes the first input/output port such that any one of the input/output ports can serve as an input port and an output port for the first wavelength component;   a second wavelength selective element for demultiplexing the second wavelength component from the WDM optical signal after the first wavelength component is demultiplexed from the WDM optical signal; and   a second optical element for directing the second wavelength component to any selected ones of the plurality of input/output ports which includes the first input/output port.   
   
   
       24 . The optical switch of  claim 23  wherein the first and second wavelength selective elements are first and second thin film filter having passbands corresponding to the first and second wavelength components, respectively. 
   
   
       25 . The optical switch of  claim 24  wherein the first and second optical elements each include tiltable mirrors. 
   
   
       26 . The optical switch of  claim 23  wherein the first wavelength selective element and the first optical element comprise a narrow band free space switch. 
   
   
       27 . The optical switch of  claim 23  further comprising a detector associated with each of the wavelength selective elements for monitoring the wavelength component it respectively demultiplexes. 
   
   
       28 . The optical switch of  claim 23  further comprising a free space region disposed along at least part of an optical path traversed by the first wavelength component between the input port and the output port. 
   
   
       29 . The optical switch of  claim 23  further comprising a free space region disposed along at least part of an optical path traversed by the second wavelength component between the input port and the second optical element. 
   
   
       30 . The optical switch of  claim 26  wherein said narrow band free space switch includes a thin film filter and a tiltable optical element. 
   
   
       31 . The optical switch of  claim 30  wherein said tiltable optical element is a tiltable mirror. 
   
   
       32 . The optical switch of  claim 23  wherein said first wavelength selective element is a bulk diffraction grating. 
   
   
       33 . The optical switch of  claim 26  further comprising a detector associated with each of the narrow band free space switches. 
   
   
       34 . The optical switch of  claim 28  wherein the free space region comprises air as a medium in which the optical signal propagates. 
   
   
       35 . The optical switch of  claim 23  wherein said first optical element is a retroreflector. 
   
   
       36 . The optical switch of  claim 23  wherein said tiltable optical element includes a tiltable mirror and a collimating lens. 
   
   
       37 . The optical switch of  claim 36  further comprising a correcting optical element disposed between the collimating lens and said tiltable mirror for reducing insertion loss. 
   
   
       38 . The optical switch of  claim 37  wherein said correcting optical element includes a convex-concave lens. 
   
   
       39 . The optical switch of  claim 38  wherein at least one surface of said convex-concave lens has a spherical radius of curvature substantially equal to a distance between a surface of the lens and the tiltable mirror.