Techniques for Reducing Polarization, Wavelength and Temperature Dependent Loss, and Wavelength Passband Width in Fiberoptic Components

Abstract

A pin hole or aperture is located or formed adjacent to the end surface of one or more of the input ports or fibers, or adjacent to one or more of the output ports or fibers, of a fiberoptic component. The aperture allows light to enter (or exit) the core of the associated fiber, and the non-transparent layer that surrounds the aperture blocks light from entering or exiting the cladding layer of the associated fiber. This blocking of the evanescent field in the cladding layer serves to reduce the polarization, wavelength, and temperature dependencies of the light coupling to the output port(s) or fiber(s) of the optical component. It can also reduce the passband width of the selected wavelength in tunable optical filter applications. The non-transparent layer surrounding the aperture can be made reflective, and light that is reflected by the non-transparent layer can be used for optical power monitoring.

1 . An optical component, comprising:
 one or more optical waveguides, including a first optical waveguide having an inner core extending in a first direction that is radially surrounded by an outer cladding along the first direction, the first optical waveguide terminating in a first end and wherein the inner core has a higher index of refraction than the index of refraction of the outer cladding; and   a non-transparent end structure covering the first end of the first optical waveguide and having a transparent aperture for at least a portion of inner core,   wherein the non-transparent end structure is reflective and the optical component is configured to monitor at least a portion of incident light reflected from the non-transparent end structure.   
     
     
         2 . The optical component of  claim 1 , wherein the first optical waveguide is an optical fiber. 
     
     
         3 . The optical component of  claim 2 , further comprising:
 a ferrule in which the optical fiber is embedded.   
     
     
         4 . The optical component of  claim 1 , wherein the optical component includes a substrate upon or within which the first optical waveguide is formed. 
     
     
         5 . (canceled) 
     
     
         6 . The optical component of  claim 1 , wherein the end structure is formed on the first end of the optical waveguide. 
     
     
         7 . The optical component of  claim 1 , wherein the end structure is formed on a plate, separate from the first end of the optical waveguide. 
     
     
         8 . The optical component of  claim 1 , wherein the inner core has a uniform index of refraction. 
     
     
         9 . The optical component of  claim 1 , wherein the inner core has a non-uniform index of refraction. 
     
     
         10 . The optical component of  claim 1 , wherein the transparent aperture has an area that is less than the area of the inner core on the first end, such that less than all of the inner core on the first end is exposed by the transparent aperture. 
     
     
         11 . The optical component of  claim 1 , wherein the transparent aperture has an area that is larger than the area of the inner core on the first end, such that all of the inner core and a portion of the cladding is exposed by the transparent aperture. 
     
     
         12 . The optical component of  claim 1 , wherein the transparent aperture has an area that is substantially equal to the area of the inner core on the first end, being aligned such that substantially all of the inner core and none of the cladding is exposed by the transparent aperture. 
     
     
         13 . The optical component of  claim 1 , wherein the first end of the first optical waveguide is angled at a non-right angle relative to the first direction. 
     
     
         14 . The optical component of  claim 1 , further comprising:
 a second optical waveguide terminating in a second end, the second end being proximate to the first end of the first optical waveguide, wherein the first and second optical waveguides are aligned such that light transmitted from the second end of the second waveguide is incident upon the first end of the first waveguide.   
     
     
         15 . An optical component, comprising:
 one or more optical waveguides, including a first optical waveguide having an inner core extending in a first direction that is radially surrounded by an outer cladding along the first direction, the first optical waveguide terminating in a first end and wherein the inner core has a higher index of refraction than the index of refraction of the outer cladding;   a non-transparent end structure covering the first end of the first optical waveguide and having a transparent aperture for at least a portion of inner core; and   a second optical waveguide terminating in a second end, the second end being proximate to the first end of the first optical waveguide, wherein the first and second optical waveguides are aligned such that light transmitted from the second end of the second waveguide is incident upon the first end of the first waveguide,   wherein the non-transparent end structure is reflective, and wherein the first and second optical waveguides are further aligned such that at least a portion of light transmitted from the second end of the second optical waveguide that is incident upon the first end of the first optical waveguide is reflected back onto the second end of the second optical waveguide, and the optical component is configured to monitor the light reflected back onto the second end of the waveguide.   
     
     
         16 - 29 . (canceled) 
     
     
         30 . The optical component of  claim 1 , wherein the optical component is further configured to determine the optical power of the at least a portion of incident light reflected from the non-transparent end structure. 
     
     
         31 . The optical component of  claim 1 , further comprising:
 a photo-detector, wherein the photodetector is configured to monitor the at least a portion of incident light reflected from the non-transparent end structure.   
     
     
         32 . The optical component of  claim 15 , wherein the optical component is further configured to determine the optical power of the at least a portion light reflected back onto the second end of the waveguide. 
     
     
         33 . The optical component of  claim 15 , further comprising:
 a photo-detector, wherein the photodetector is configured to monitor the at least a portion of light reflected back onto the second end of the waveguide.   
     
     
         34 . An optical device, comprising:
 one or more optical waveguides, including a first optical waveguide having an inner core extending in a first direction that is radially surrounded by an outer cladding along the first direction, the first optical waveguide terminating in a first end and wherein the inner core has a higher index of refraction than the index of refraction of the outer cladding;   a non-transparent end structure covering the first end of the first optical waveguide and having a transparent aperture for at least a portion of inner core, wherein the non-transparent end structure is reflective; and   a photo-detector configured such that a portion of a beam of light incident on the end structure is reflected thereon, wherein the photo-detector is further configured to determine the optical power of the portion of the beam of light.   
     
     
         35 . The optical device of  claim 34 , wherein the first optical waveguide is an optical fiber. 
     
     
         36 . The optical device of  claim 35 , further comprising:
 a ferrule in which the optical fiber is embedded.   
     
     
         37 . The optical device of  claim 34 , wherein the end structure is formed on the first end of the optical waveguide. 
     
     
         38 . The optical device of  claim 34 , wherein the end structure is formed on a plate, separate from the first end of the optical waveguide. 
     
     
         39 . The optical device of  claim 34 , wherein the inner core has a uniform index of refraction. 
     
     
         40 . The optical device of  claim 34 , wherein the inner core has a non-uniform index of refraction. 
     
     
         41 . The optical device of  claim 34 , wherein the transparent aperture has an area that is less than the area of the inner core on the first end, such that less than all of the inner core on the first end is exposed by the transparent aperture. 
     
     
         42 . The optical device of  claim 34 , wherein the transparent aperture has an area that is larger than the area of the inner core on the first end, such that all of the inner core and a portion of the cladding is exposed by the transparent aperture. 
     
     
         43 . The optical device of  claim 34 , wherein the transparent aperture has an area that is substantially equal to the area of the inner core on the first end, being aligned such that substantially all of the inner core and none of the cladding is exposed by the transparent aperture. 
     
     
         44 . The optical device of  claim 34 , wherein the first end of the first optical waveguide is angled at a non-right angle relative to the first direction. 
     
     
         45 . The optical device of  claim 34 , further comprising:
 a second optical waveguide terminating in a second end, the second end being proximate to the first end of the first optical waveguide, wherein the first and second optical waveguides are aligned such that light transmitted from the second end of the second waveguide is incident upon the first end of the first waveguide.