Pixellated WDM optical components

Abstract

A micromirror array is used to form optical apparatus useful in WDM optical networks. In one embodiment, the micromirror array is used to insert a desired attenuation in individual channels for purposes such as equalization. In another embodiment, the micromirror array is used to form an optical monitor useful as an optical spectrum analyzer.

What is claimed:  
     
         1 . Apparatus for inserting a controlled amount of attenuation in the power level of individual channels of a wavelength-division multiplex waveguide optical signal comprising: 
 a panel comprising a plurality of microelements that can each selectively be made either to transmit or not to transmit incident light in a desired direction suitable for recombining the light, the elements being arranged in a two-dimensional array essentially of rows and columns;    an input port adapted to be supplied with an input wavelength division multiplexed signal to be treated;    an output port adapted for providing for further transmission of the optical signal after treatment; and    means positioned for receiving the optical signal from the input port, separating the signal into individual channel signals directing the different channel signals along different paths for incidence on different portions of the panel, collecting and combining the amount of light of different channels transmitted after incidence on the panel and directing the collected light to an output port for further transmission.    
     
     
         2 . Apparatus in accordance with    claim 1    in which the panel comprises an array of micromirrors each of which is tiltable either to direct or not to direct incident light along a selected direction for recombination.  
     
     
         3 . Apparatus in accordance with    claim 1    in which the panel comprises an array of elements, each of which can be made to transmit incident light in a desired direction for recombination or to absorb it.  
     
     
         4 . Apparatus for inserting a controlled amount of attenuation in the power level of individual channels of a wavelength division multiplexed optical signal comprising: 
 a micromirror array panel having a plurality of micromirrors arranged in rows and columns, each mirror being tiltable;    an input port adapted to be supplied with a wavelength-division-multiplexed optical signal to be affected;    an output port adapted for providing for further transmission of the optical signal after it has been affected;    a dispersive element positioned for receiving the optical signal from the input port, separating the signal into individual channels, directing the different channels along different paths for incidence on different portions of the micromirror-array panel, collecting and combining the different channels reflected towards it into a single beam after incidence on the panel, and for directing the single beam to the output port; and    a circuit for providing control signals to the panel for controlling the tilt of the mirrors that are to reflect incident light received from the dispersive element back towards the dispersive element for combining and directing it back to the output port.    
     
     
         5 . Apparatus of    claim 4    in which the dispersive element comprises a diffraction grating.  
     
     
         6 . Apparatus of    claim 4    in which the dispersive element comprises a prism.  
     
     
         7 . Apparatus in accordance with    claim 4    in which the dispersive element is an arrayed-waveguide-grating router  
     
     
         8 . Apparatus in accordance with    claim 4    in which the different portions are different single columns of micromirrors.  
     
     
         9 . Apparatus in accordance with    claim 4    in which the different portions are different groups of a plural number of adjacent columns of mirrors.  
     
     
         10 . Apparatus for inserting a controlled attenuation in the power level of individual channels of an optical signal including a plurality of channels of different wavelengths comprising: 
 micromirror panel having a plurality of micromirrors arranged in a two dimensional planar array, each mirror in the array being tiltable; and    means for receiving an input optical signal including a plurality of channels of different wavelengths for separating the channels and directing the light of each for incidence on a different portion of the micromirror panel and for combining into the output signal the light reflected from the different portions of the micromirror panel having the appropriate tilt to be combined.    
     
     
         11 . Apparatus in accordance with    claim 10    in which said means comprises a dispersive element positioned in the path of the input optical signal and in the path of the reflected light to be recombined into the output signal.  
     
     
         12 . Apparatus in accordance with    claim 10    in which sad means comprises an arrayed-waveguide-grating router.  
     
     
         13 . Apparatus in accordance with    claim 10    in which said means comprises a diffraction grating.  
     
     
         14 . Apparatus in accordance with    claim 10    in which the micromirrors are arranged in rows and columns and the attenuation is controlled by controlling the number of mirrors for each channel whose tilt is such as to reflect the light back for collection for the output signal.  
     
     
         15 . Apparatus in accordance with    claim 10    in which there is included provision for collecting for utilization light reflected from mirrors having other than the appropriate tilt for combining in the output signal.  
     
     
         16 . Apparatus in accordance with    claim 10    in which the dispersive means comprises an arrayed-waveguide-grating router.  
     
     
         17 . Apparatus in accordance with    claim 10    in which the input optical signal is provided from a first optical fiber and the combined output light is supplied to a second optical fiber.  
     
     
         18 . An optical power spectrum analyzer comprising: 
 a micromirror-array panel having a plurality of columns of tiltable micromirrors;    a dispersive element for receiving an input optical signal including a plurality of different wavelength components, separating the optical signal into the individual wavelength components and directing them separately at the micromirror array panel such that different wavelength components are incident on different columns of the micromirrors of the panel;    an optoelectronic detector for receiving optical signals reflected from the panel for conversion to electrical signals; and    a control circuit for tilting in succession groups of adjacent columns of the panel for directing the light incident on such tilted group for interception by the optoelectronic detector for providing an electrical signal that is a measure of the power level of the wavelength component incident on the group of mirrors of the array at the time such group was tilted for interception.    
     
     
         19 . The optical power spectrum analyzer of    claim 18    in which the dispersive element is a diffraction grating.  
     
     
         20 . The optical power spectrum analyzer of    claim 18    in which there is more than one column of mirrors in each group of the array associated with each wavelength component and each wavelength component is incident on a different single group of columns of the array.  
     
     
         21 . The optical power spectrum analyzer of    claim 18    in which each group consists of only a single column of the array.