Tunable bragg grating devices employing the same

Abstract

The present invention relates generally to electro-optically active waveguide segments, and more particularly to the use of a selective voltage input to control the phase, frequency and/or amplitude of a propagating wave in the waveguide. Particular device structures and methods of manufacturing are described herein.

1. A method for manufacturing an electro-optic waveguide segment having a core and a cladding; the method comprising the steps of:
 forming a Bragg grating in said waveguide segment;    removing a first selective portion of said cladding above at least a portion of said Bragg grating to form a first recess within said cladding, said first selective portion having an outer dimension which is less than an unmodified section of said cladding;    depositing a first electrically conductive material covering at least part of said first selective portion and in direct contact with a deepest portion of said first recess, thereby forming a first electrode, wherein there are substantially no air gaps between said first electrode and said first recess;    removing a second selective portion of said cladding to form a second recess within said cladding, said second selective portion having an outer dimension which is less than an unmodified section of said cladding, said first and second selected portions not contacting one-another;    depositing a second electrically conductive material covering at least part of said second selective portion and in direct contact with a deepest portion of said of said second recess, thereby forming a second electrode, wherein there are substantially no air gaps between said second electrode and said second recess; and    poling said waveguide segment using at least a electric field applied to either said first or second electrode to induce an non-linearity in said waveguide segment.    
     
     
       2. The method recited in  claim 1 , wherein said first recess is substantially filled with said first electrically conductive material. 
     
     
       3. The method recited in  claim 2 , wherein said first electrically conductive material is optically transparent. 
     
     
       4. The method recited in  claim 1 , wherein said second recess is substantially filled with a second electrically conductive material. 
     
     
       5. The method recited in  claim 4 , wherein said second electrically conductive material is optically transparent. 
     
     
       6. The method recited in  claim 1  wherein said poling step is performed using ultraviolet light injected into said waveguide segment in combination with said electric field. 
     
     
       7. The method recited in  claim 1 , wherein said poling step is performed using said electrical field in combination with heating said waveguide segment. 
     
     
       8. A method for manufacturing an electro-optic waveguide segment having a core and a cladding; the method comprising the steps of:
 forming a Bragg grating in said waveguide segment;    removing a first selective portion of said cladding above at least a portion of said Bragg grating to form a first recess within said cladding, said first selective portion having an outer dimension which is less than an unmodified section of said cladding;    depositing a first electrically conductive material covering at least part of said first selective portion and in direct contact with a deepest portion of said first recess, thereby forming a first electrode, wherein there are substantially no air gaps between said first electrode and said first recess;    removing a second selective portion of said cladding to form a second recess within said cladding, said second selective portion having an outer dimension which is less than an unmodified section of said cladding, said first and second selected portions not contacting one-another;    depositing a second electrically conducive material covering at least part of said second selective portion and in direct contact with a deepest portion of said second recess, thereby forming a second electrode, wherein there are substantially no air gaps between said second electrode and said second recess; and    poling said waveguide segment using ultraviolet light injected into said waveguide segment to induce an non-linearity in said waveguide.    
     
     
       9. A method for manufacturing an electro-optic waveguide segment having a core and a cladding; the method comprising the steps of:
 forming a Bragg grating in said waveguide segment; 
 removing a first selective portion of said cladding above at least a portion of said Bragg grating to form a first recess within said cladding, said first selective portion having an outer dimension which is less than an unmodified section of said cladding;  
   depositing a first electrically conductive material covering at least part of said first selective portion and in direct contact with a deepest portion of said first recess, thereby forming a first electrode, wherein there are substantially no air gaps between said first electrode and said first recess; 
 removing a second selective portion of said cladding to form a second recess within said cladding, said second selective portion having an outer dimension which is less than an unmodified section of said cladding, said first and second selected portions not contacting one-another;  
   depositing a second electrically conductive material covering at least part of said second selective portion and in direct contact with a deepest portion of said second recess; and    poling said waveguide segment by heating said waveguide segment in combination with ultraviolet light injected into said waveguide segment to induce an non-linearity in said waveguide segment.    
     
     
       10. A method for manufacturing an electro-optic waveguide segment having a core and a cladding; the method comprising the steps of:
 removing a first selective portion of said cladding to form a first recess within said cladding, said first selective portion having an outer dimension which is less than an unmodified section of said cladding;    removing a second selective portion of said cladding to form a second recess within said cladding, said second selective portion having an outer dimension which is less than an unmodified section of said cladding, said first and second selected portions not contacting one another;    depositing a first electrically conductive material within said first recess and in direct contact with a deepest portion of said first recess, thereby forming a first electrode, wherein there are substantially no air gaps between said first electrode and said first recess;    depositing a second electrically conductive material within said second recess and in direct contact with a deepest portion of said second recess, thereby forming a second electrode, wherein there are substantially no air gaps between said second electrode and said second recess; and    poling said waveguide segment using at least a electric field applied to said first and second selective portions to induce a non-linearity in said waveguide segment.    
     
     
       11. The method for manufacturing recited in  claim 10 , further comprising the step of forming a Bragg grating in said waveguide segment. 
     
     
       12. An optical switch, comprising:
   first and second optical fibers, each having an input and an output, the first optical fiber input being configured to receive an unpolarized input light signal;        a first polarization beam - splitter coupled to the first and second optical fibers and configured to convert the unpolarized input light signal in the first optical fiber to a first linear polarization state and to convert the unpolarized input light signal to a second linear polarization state, orthogonal to the first linear polarization state, in the second optical fiber;        a first electro - optic waveguide disposed in the first optical fiber and configured for operation in a first operational state to pass the light having the first linear polarization state in an unaltered polarization form and configured for operation in a second operational state to rotate the polarization of light having the first linear polarization state;        a second electro - optic waveguide disposed in the second optical fiber, and configured for operation in the first operational state to pass the light having the second linear polarization state in the unaltered polarization form and configured for operation in the second operational state to rotate the polarization of light having the second linear polarization state; and        a second polarization beam - splitter coupled to first and second optical fibers and configured to combine the light from the first and second optical fibers into an unpolarized output light signal at the first optical fiber output when the first and second electro - optic waveguides are configured for operation in the first operational state and to combine the light from the first and second optical fibers into an unpolarized output light signal at the second optical fiber output when the first and second electro - optic waveguides are configured for operation in the second operational state wherein the optical switch operates in a non - interferometric manner.     
     
     
       13. The switch of  claim 12  wherein the first and second electro- optic waveguides each include a control input for selection of the first or second operational state.   
     
     
       14. The switch of  claim 13  wherein the first and second electro- optic waveguide control inputs are configured to accept a control input signal having a first discrete signal level for selection of the first operational state and a second discrete signal level for selection of the second operational state.   
     
     
       15. The switch of  claim 13  wherein the first and second electro- optic waveguides control inputs are configured to accept a variable control signal wherein the first and second electro - optic waveguides are configured for variable operation between the first and second operational states in dependence on a level of the variable control signal whereby an amplitude modulated output light is produced in the first and second optical fibers.   
     
     
       16. The switch of  claim 13  wherein the first and second electro- optic waveguide control inputs are configured to accept an input voltage for selection of the first or second operational state.   
     
     
       17. The switch of  claim 12  wherein the first and second electro- optic waveguides are poled electro - optic waveguides.   
     
     
       18. The switch of  claim 12  wherein the first polarization beam- splitter is configured to convert the input light signal to the first and second orthogonal linear polarization states comprising a vertical polarization and a horizontal polarization, respectively.   
     
     
       19. The switch of  claim 18  wherein the second polarization beam- splitter is configured to combine light having the vertical polarization and light having the horizontal polarization in the first optical fiber when the first and second electro - optic waveguides are configured for operation in the first operational state.   
     
     
       20. The switch of  claim 18  wherein the second polarization beam- splitter is configured to combine light having the rotated vertical polarization and light having the rotated horizontal polarization in the second optical fiber when the first and second electro - optic waveguides are configured for operation in the second operational state.   
     
     
       21. The switch of  claim 12  wherein the first electro- optic waveguide disposed in the first optical fiber further comprises the first electro - optic waveguide disposed in a first section of optical fiber and spliced to a second section of optical fiber.   
     
     
       22. A method of optical switching, comprising:
   receiving an input light signal having an unpolarized polarization state;        converting the polarization state of the input light signal to a first linear polarization state in a first optical fiber and to a second orthogonal linear polarization state in a second optical fiber;        in a first operational state, passing the light having the first linear polarization state and the light having the second linear polarization state in an unaltered form;        combining the light having the first and second linear polarization states to produce light having both orthogonal linear polarization states in the first optical fiber when operating in the first operational state;        in a second operational state, rotating the polarization of light first optical fiber from the first linear polarization state to the second linear polarization state and rotating the polarization of light in the second optical fiber from the second linear polarization state to the first linear polarization state; and        combining the light having the rotated first and second linear polarization states to produce light having both orthogonal linear polarization states in the second optical fiber when operating in the second operational state.     
     
     
       23. The method of  claim 22 , further comprising accepting control input signal for selection of the first or second operational state. 
     
     
       24. The method of  claim 23  wherein accepting the control input signal comprises accepting a control input signal having a first discrete signal level for selection of the first operational state and a second discrete signal level for selection of the second operational state. 
     
     
       25. The method of  claim 23  wherein accepting the control input signal comprises accepting a control inpt signal having a variable signal level to permit variable operation between the first and second operational states in dependence on a level of the variable control signal whereby an amplitude output light is produced in the first and second optical fibers. 
     
     
       26. The method of  claim 22  wherein converting the polarization state of the input light signal to the first and second orthogonal linear polarization states is performed by a polarization beam splitter disposed along the first and second optical fibers. 
     
     
       27. The method of  claim 22  wherein rotating the polarization of light having two orthogonal linear polarization states is performed by first and second electro- optic waveguides disposed in the first and second optical fibers, respectively.   
     
     
       28. The method of  claim 27  wherein the first and second electro- optic waveguides are poled electro - optic waveguides.   
     
     
       29. The method of  claim 22  wherein converting the polarization state of the input light signal to the first and second linear polarization states comprises converting the polarization state of the input light signal to orthogonal linear polarization states comprising a vertical polarization and a horizontal.