Planar lightwave wavelength blocker devices using micromachines

Abstract

A method and apparatus are disclosed for selectively passing or blocking an optical signal using an opaque or reflective shutter that is selectively positioned in or out of the light path. The disclosed wavelength blocker can be employed to filter input wavelength-division multiplexed (WDM) signal comprised of N wavelength channels, where a mechanical shutter array selectively passes each of the N wavelength channels. Each mechanical shutter may be controlled, for example, by a micromachine control element that physically lifts the shutter into or out of the lightpath. The disclosed wavelength blockers may be utilized in wavelength-selective cross connects, as well as other optical devices. In an exemplary wavelength-selective cross connect, an array of mirrors are employed in a planar waveguide having two sets of waveguide gratings intersecting at an angle. The mirrors and waveguide gratings are positioned such that if the mirror for a given channel is up (removed from the light path), then that channel passes across the device and exits the corresponding output port (bar state), otherwise the light is reflected by the mirror and exits the opposite output port (bar state).

I claim:  
     
         1 . A planar optical device for filtering an optical signal, the optical device comprising: 
 an input waveguide for carrying said optical signal;    an output waveguide for carrying said optical signal and    a mechanical shutter for coupling said input and output waveguides, said mechanical shutter selectively positioned in or out of said lightpath to selectively block or pass said optical signal.    
     
     
         2 . The optical device according to  claim 1 , wherein said optical signal is a wavelength-division multiplexed (WDM) signal comprising N wavelength channels and wherein said optical device further comprises a demultiplexer for producing a plurality of demultiplexed output signals from said input WDM signal, a multiplexer for producing an output WDM signal, and a mechanical shutter associated with each of said N wavelength channels.  
     
     
         3 . The optical device according to  claim 2 , wherein a plurality of said waveguides carry each of said N wavelength channels.  
     
     
         4 . The optical device according to  claim 2 , wherein said demultiplexer is embodied as a waveguide grating and wherein an aperture of said waveguide grating is substantially larger than an aperture of said mechanical shutter.  
     
     
         5 . The optical device according to  claim 1 , wherein said shutter is opaque.  
     
     
         6 . The optical device according to  claim 1 , wherein said shutter is a reflective surface.  
     
     
         7 . The optical device according to  claim 1 , wherein said shutter is controlled by a micromachine control element that positions said shutter in and out of said lightpath.  
     
     
         8 . A method for filtering an optical signal in a planar optical device, said method comprising the steps of: 
 receiving said optical signal on an input waveguide;    coupling said input waveguide to an output waveguide; and    selectively blocking or passing said optical signal using a mechanical shutter.    
     
     
         9 . The method according to  claim 8 , wherein said optical signal is a wavelength-division multiplexed (WDM) signal comprising N wavelength channels and wherein said method further comprises the step of producing a plurality of demultiplexed output signals from said input WDM signal using a demultiplexer.  
     
     
         10 . The method according to  claim 9 , wherein a plurality of said waveguides carry each of said N wavelength channels.  
     
     
         11 . The method according to  claim 9 , wherein said demultiplexer is embodied as a waveguide grating and wherein an aperture of said waveguide grating is substantially larger than an aperture of said mechanical shutter.  
     
     
         12 . The method according to  claim 8 , wherein said shutter is opaque.  
     
     
         13 . The method according to  claim 8 , wherein said shutter is a reflective surface.  
     
     
         14 . The method according to  claim 8 , wherein said shutter is controlled by a micromachine control element that positions said shutter in and out of said lightpath.  
     
     
         15 . A wavelength-selective cross connect (WSC) having a plurality of input ports and output ports for selectively passing or crossing an incoming signal received on one of said input ports to a corresponding output port or to an opposite output port, said WSC comprising: 
 a first set of waveguide gratings corresponding to said input ports;    a second set of waveguide gratings corresponding to said output ports, wherein said first and second sets of waveguide gratings intersect at an angle;    a reflective shutter array for coupling said first and second sets of waveguide gratings, said reflective shutter selectively positioned in or out of said lightpath to selectively reflect or pass said signal, whereby in a bar state a given channel passes across said WSC and exits a corresponding output port or in a cross state said channel is reflected and exits an opposite output port.    
     
     
         16 . The WSC according to  claim 15 , wherein said shutter array is controlled by a micromachine control element that positions said shutter in and out of said lightpath.  
     
     
         17 . The WSC according to  claim 15 , wherein an aperture of said waveguide gratings is substantially larger than an aperture of said reflective shutter.  
     
     
         18 . A wavelength add-drop (WAD) multiplexer having an input port and an output port for selectively removing or adding light of a given wavelength to an optical signal comprising N wavelength channels, said WAD comprising: 
 a first waveguide grating corresponding to said input port;    a second waveguide grating corresponding to said output port;    a first waveguide lens corresponding to a drop port;    a second waveguide lens corresponding to an add port;    a reflective shutter array for coupling said first and second waveguide gratings and first and second waveguide lenses, said reflective shutter selectively positioned in or out of said lightpath to selectively reflect or pass said signal, whereby in a first state a given channel passes across said WAD and exits said output port or in a second state said channel is reflected and exits said drop port and signals from said add port are multiplexed together and sent to said output port.    
     
     
         19 . The WAD multiplexer according to  claim 18 , wherein said shutter array is controlled by a micromachine control element that positions said shutter in and out of said lightpath.  
     
     
         20 . The WAD according to  claim 18 , wherein an aperture of said waveguide gratings is substantially larger than an aperture of said reflective shutter.