Optical device and a method of processing a digital optical signal in parallel and in free space

Abstract

An optical device for processing a digital optical signal in parallel and in free space, the said device comprising: a) means of input in guided propagation of a digital optical signal comprising at least one temporal series of n bits; b) means capable of converting the said digital optical signal to a beam of n digital optical signals in guided propagation, each comprising at least one temporal series of n bits; c) means capable of converting the said beam of n digital optical signals in guided propagation, each comprising the said at least one temporal series of n bits, to a beam of n digital optical signals in free space; d) means capable of selecting, in parallel and in free space, a bit preselected from the said at least one temporal series of n bits of each of the said n digital optical signals, so as to transform the said at least one temporal series of n bits into a spatial figure of the said n bits which carries the same information as that previously contained in the said at least one temporal series, the said device further comprising e) optical means capable of modifying, in parallel and in free space, at least one bit of the said spatial figure of the said n bits, the said means being selected by a group comprising means capable of eliminating at least one bit, means capable of inserting at least one bit and means capable of modifying the form of at least one bit, and f) means of output of a processed digital optical signal, comprising at least one series of n bits.

1 . An optical device for processing a digital optical signal in parallel and in free space, the said device comprising: 
 a) means of input in guided propagation of a digital optical signal comprising at least one temporal series of n bits;    b) means capable of converting the said digital optical signal to a beam of n digital optical signals in guided propagation each comprising the said at least one temporal series of n bits;    c) means capable of converting the said beam of n digital optical signals in guided propagation, each comprising the said at least one temporal series of n bits, to a beam of n digital optical signals in free space;    d) means capable of selecting, in parallel and in free space, a bit preselected from the said at least one temporal series of n bits of each of the said n digital optical signals, so as to transform the said at least one temporal series of n bits into a spatial figure of the said n bits which carries the same information as that previously contained in the said at least one temporal series,    characterised in that the said device further comprises    e) optical means capable of modifying, in parallel and in free space, at least one bit of the said spatial figure of the said n bits, the said means being selected by the group comprising means capable of eliminating at least one bit, means capable of inserting one bit and means capable of modifying the form of at least one bit, and    f) means of output of the said at least one bit of the said spatial figure of n bits.    
     
     
         2 . A device according to    claim 1   , characterised in that the said means capable of selecting, in parallel and in free space, a bit preselected from the said at least one temporal series of n bits of each of the said n digital optical signals so as to transform the said at least one temporal series of n bits into a spatial figure of the said n bits which carries the same information as that previously contained in the said at least one temporal series comprise: 
 a) a first optical switching module;    b) a second optical switching module arranged in series in relation to the said first optical switching module;    c) means of supplying to the said first and, respectively, to the said second optical switching module at least one pair of a first and a second beam of optical control pulses having a predetermined time interval between each other;    d) a dichroic mirror capable of guiding the said at least one pair of a first and a second beam of optical control pulses in collinear mode in relation to the direction of propagation of the said n digital optical signals;    e) means of collimation for guiding in free space the said at least one pair of a first and a second beam of optical control pulses in such a way that they are incident upon the said dichroic mirror at a pre-established angle.    
     
     
         3 . A device according to    claim 2   , characterised in that the said first and second optical switching modules comprise a first and, respectively, a second element  200  and  400  capable of causing the plane of polarization of the said n digital optical signals in free space to rotate by a predetermined angle under the action of the said at least one pair of a first and a second beam of optical control pulses, and also comprise a first and a second polarization analyzer respectively capable of filtering, along a predetermined plane of polarization, the said n digital optical signals output from the said first and respectively second elements.  
     
     
         4 . A device according to    claim 3   , characterised in that the said first and second elements consist of a first and a second indium-doped cadmium tellurium (CdTe:In) monocrystal.  
     
     
         5 . A device according to    claim 3    or    claim 4   , characterised in that the said first and second polarization analyzers are oriented essentially orthogonal to each other.  
     
     
         6 . A device according to any of the previous claims, characterised in that the said means of output comprise means of optical focusing capable of guiding the said spatial figure of n bits in free space in means of guided propagation.  
     
     
         7 . A device according to any of the previous claims, characterised in that the said means of output comprise n lines capable of interval-timing the said n bits of the said spatial figure in predetermined time intervals.  
     
     
         8 . A device according to    claim 7   , characterised in that the said means of output also comprise means capable of conveying the said n bits, interval-timed and in guided propagation, to a processed digital optical signal comprising at least one temporal series of n bits.  
     
     
         9 . A device according to any of the previous claims, characterised in that the said means of elimination of the said at least one bit of the said spatial figure of n bits comprise a third switching module and means of supplying at least one elimination optical signal.  
     
     
         10 . A device according to    claim 9   , characterised in that the said third switching module comprises an element capable of causing the plane of polarization of at least one of the said n digital optical signals output from n interval timing lines and from means of collimation, to rotate by a predetermined angle, under the action of at least one optical elimination signal and in that it also comprises a polarization analyzer capable of filtering, along a predetermined plane of polarization, the said n digital optical signals output from the said element.  
     
     
         11 . A device according to    claim 10   , characterised in that the said element consists of an indium-doped cadmium tellurium (CdTe:In) monocrystal.  
     
     
         12 . A device according to any of the previous claims from  9  to  11 , characterised in that the said at least one optical elimination signal is collinear to and overlaps a single one of the said n digital optical signals output from the said n interval-timing lines.  
     
     
         13 . A device according to any of the previous claims from  9  to  12 , characterised in that the said means of elimination of the said at least one bit of the said spatial figure of n bits also comprise, downstream of the said third switching module, means transparent to the wavelength of the said n digital optical signals and capable of reflecting the wavelength of the said at least one optical elimination signal.  
     
     
         14 . A device according to any of the previous claims, characterised in that the said means capable of inserting at least one bit into the said spatial figure of n bits comprise means of supplying at least one optical insertion signal to the said first and second optical switching modules.  
     
     
         15 . A device according to    claim 14   , characterised in that the said at least one optical insertion signal has the same wavelength and power as the optical signals constituting the said spatial figure of n bits.  
     
     
         16 . A device according to    claim 14    or    claim 15   , characterised in that the said means of supplying at least one optical insertion signal also comprise the following means: 
 transparent to half the power of the said n digital optical signals and of the said at least one optical insertion signal, and  
 capable of reflecting the other half of said power.  
 
     
     
         17 . A device according to    claim 16   , characterised in that the said transparent means consist of a 50/50 optical beam splitter.  
     
     
         18 . A device according to    claim 17   , characterised in that the said 50/50 optical beam splitter is essentially inclined at an angle of 45° in relation to the direction of the said n digital optical signals and the direction of the said at least one optical insertion signal, the direction of the said n digital optical signals being essentially orthogonal to the direction of the said at least one optical insertion signal.  
     
     
         19 . A device according to    claim 17    or    claim 18   , characterised in that the said means of supplying the said at least one optical insertion signal also comprise means capable of collimating in free space the said at least one optical insertion signal so that they are incident at an angle of approximately 45° upon the said 50/50 beam splitter and overlap one of the said n digital optical signals.  
     
     
         20 . A device according to any of the previous claims from  14  to  19 , characterised in that the said means of supplying at least one optical insertion signal also comprise means of controlling and, if necessary, varying their state of polarization.  
     
     
         21 . A device according to any of the previous claims, characterised in that the said means of modifying the form of the said at least one bit of the said spatial figure of n bits comprise means capable of varying the said temporal interval between the said first and second beam of optical control pulses of the said at least one pair of a first and a second beam of optical control pulses.  
     
     
         22 . A device according to    claim 7   , characterised in that the said n lines interval-time at least one bit of the said spatial figure of n bits by a time such that the said at least one output bit is delayed in relation to the other bits of the said spatial figure of n bits, by a quantity different from the bit time which the said output bit had in input.  
     
     
         23 . A device according to any of the previous claims, characterised in that it further comprises means capable of executing algebraic operations on the said spatial figure of n bits.  
     
     
         24 . A device according to any of the previous claims, characterised in that it further comprises means capable of executing symmetry operations on the said spatial figure of n bits.  
     
     
         25 . A device according to    claim 23   , characterised in that the said means capable of executing the said algebraic operations comprise at least one element capable of causing the plane of polarization of the said n bits of the said spatial figure output from the said first and second optical switching modules to rotate by a predetermined angle, under the action of an optical laser enabling the said algebraic operations.  
     
     
         26 . A device according to    claim 23    or    claim 25   , characterised in that the said means capable of executing the said operations also comprise at least one transparent means to one first predetermined plane of polarization of the said n bits of the said spatial figure, the said transparent means also being capable of deflecting a second plane of polarization essentially orthogonal to the said first plane.  
     
     
         27 . A device according to any of the previous claims  23 ,  25  or  26 , characterised in that the said means capable of executing the said algebraic operations also comprise at least one mirror capable of reflecting the said n bits of the said spatial figure.  
     
     
         28 . A device according to    claim 24   , characterised in that the said means capable of executing the said symmetry operations comprise at least one element capable of causing the plane of polarization of the said n bits of the said spatial figure output from the said first and second optical switching module to rotate by a predetermined angle under the action of an optical beam enabling the said symmetry operations.  
     
     
         29 . A device according to    claim 24    or    claim 38   , characterised in that the said means capable of executing the said symmetry operations also comprise at least one transparent means to one first predetermined plane of polarization of the said n bits of the said spatial figure, the said transparent means also being capable of deflecting a second plane of polarization essentially orthogonal to the said first plane.  
     
     
         30 . A device according to any of the previous claims  24 ,  28  or  29 , characterised in that the said means capable of executing the said symmetry operations also comprise means capable of reflecting the said n bits of the said spatial figure.  
     
     
         31 . A device according to    claim 24    or any of the previous claims from  28  to  30 , characterised in that the said means capable of executing the said symmetry operations also comprise means capable of varying the state of polarization of the said n bits of the said spatial figure.  
     
     
         32 . A method of processing a digital optical signal in parallel and in free space, the said method comprising the steps of: 
 a) feeding a digital optical signal comprising at least one temporal series of n bits;    b) converting the said digital optical signal to a beam of n digital optical signals in guided propagation, each comprising the said at least one temporal series of n bits;    c) converting the said beam of n digital optical signals in guided propagation, each comprising the said at least one temporal series of n bits, to a beam of n digital optical signals in free space;    d) selecting, in parallel and in free space, a predetermined bit from the said at least one temporal series of n bits of each of the said n digital optical signals, so as to transform the said at least one temporal series of n bits into a spatial figure of the said n bits which carries the same information as that previously contained in the said at least one temporal series, characterised in that the said method further comprises the step of modifying in parallel and in free space at least one bit of the said spatial figure of the said n bits.    
     
     
         33 . A device according to    claim 32   , characterised in that the said step of modifying the said spatial figure comprises eliminating at least one bit.  
     
     
         34 . A method according to    claim 32    or    claim 33   , characterised in that the said step of modifying the said spatial figure comprises inserting at least one bit.  
     
     
         35 . A method according to any of the claims from  32  to  34 , characterised in that the said step of modifying the said spatial figure comprises modifying the form of at least one bit.  
     
     
         36 . A method according to any of the claims from  32  to  35 , characterised in that the said step of modifying the said spatial figure comprises translating at least one bit from one position to another position in the said spatial figure.  
     
     
         37 . A method according to any of the previous claims from  32  to  36 , characterised in that the said spatial figure of n bits in free space thus modified is re-converted to at least one temporal series of n bits and guided in output.  
     
     
         38 . A method according to    claim 37   , characterised in that the time duration of at least one bit of the said temporal series of n bits guided in output is modified.  
     
     
         39 . A device for modifying the time duration of at least one bit of a temporal series of n bits transformed into a corresponding spatial figure, characterised in that 
 the said n bits of the said spatial figure are guided in a beam of n optical guides at the end of which the said n bits are further guided in a single optical guide in the form of a temporal series of n bits, and in that    the said beam of n optical guides comprises at least one section of optical guide having a length preselected such that in input to the said single optical guide one bit which has travelled along the said section is separated from at least one of the other bits of the said series by a time interval different from that by which it was separated in the initial temporal series.