Method for polishing fiber optic ferrules
DCFirst Claim
1. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
- obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; and
imparting a spherical end face to the distal end of the ferrule, adjacent the chamfer surface, the spherical end face having a periphery which is inclined with respect to a plane normal to the bore, defining an angle of inclination, the spherical end face further having a tangent at the bore which is parallel with the angle of inclination, said imparting step being accomplished byforming a fiat surface at the distal end of the ferrule, oriented with respect to the normal plane of the bore at the angle of inclination, andpolishing the fiat surface against a compliant pad while maintaining the ferrule at an oblique angle with respect to the pad, the oblique angle being greater than the angle of inclination.
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Abstract
A method of polishing ferrules used in optical fiber connectors centers the apex of the spherical end face of the ferrule on the fiber axis. The invention is directed to ferrules whose ends are angled and generally spherical, providing angled physical contact (APC) between a pair of interconnected fibers. These ferrules commonly have a chamfer from the outermost diameter leading to the spherical, angled end face. In such prior art ferrules, the apex of the spherical end face does not coincide with the fiber axis, leading to a potential gap between the fiber ends, which affects several performance factors, including insertion loss, stability and repeatability. The present invention provides several practical methods for imparting an APC finish to a chamfered ferrule while maintaining the apex of the spherical end face on the fiber axis.
28 Citations
19 Claims
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1. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
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obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; and imparting a spherical end face to the distal end of the ferrule, adjacent the chamfer surface, the spherical end face having a periphery which is inclined with respect to a plane normal to the bore, defining an angle of inclination, the spherical end face further having a tangent at the bore which is parallel with the angle of inclination, said imparting step being accomplished by forming a fiat surface at the distal end of the ferrule, oriented with respect to the normal plane of the bore at the angle of inclination, and polishing the fiat surface against a compliant pad while maintaining the ferrule at an oblique angle with respect to the pad, the oblique angle being greater than the angle of inclination. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
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obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; forming a flat surface at the distal end of the ferrule, adjacent to the chamfer surface, said flat surface being inclined with respect to a plane normal to said bore, defining an angle of inclination, and said forming step removing a portion of the chamfered surface; and converting said flat surface into a spherical surface having a tangent at the bore which is parallel with the angle of inclination, by grinding the distal end of the ferrule to form a uniform chamfer about the periphery of the flat surface, and polishing the flat surface against a compliant pad. - View Dependent Claims (9, 10, 11)
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12. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
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obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; and imparting a spherical end face to the distal end of the ferrule, adjacent the chamfer surface, the spherical end face having a periphery which is inclined with respect to a plane normal to the bore, defining an angle of inclination, the spherical end face further having a tangent at the bore which is parallel with the angle of inclination, said imparting step being accomplished by forming a flat, inclined surface at the distal end of the ferrule, thereby removing a portion of the chamfer surface, grinding the distal end of the ferrule to form a uniform chamfer about the periphery of the flat, inclined surface, and polishing the flat, inclined surface against a compliant pad.
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13. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
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obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; and imparting a spherical end face to the distal end of the ferrule, adjacent the chamfer surface, the spherical end face having a periphery which is inclined with respect to a plane normal to the bore, defining an angle of inclination, the spherical end face further having a tangent at the bore which is parallel with the angle of inclination, said imparting step being accomplished by forming a convex surface at the distal end of the ferrule, oriented with respect to the normal plane of the bore at the angle of inclination, and polishing the convex surface against a compliant pad while maintaining the ferrule at an oblique angle with respect to the pad, the oblique angle being greater than the angle of inclination. - View Dependent Claims (14)
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15. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
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obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; and imparting a spherical end face to the distal end of the ferrule, adjacent the chamfer surface, the spherical end face having a periphery which is inclined with respect to a plane normal to the bore, defining an angle of inclination, the spherical end face further having a tangent at the bore which is parallel with the angle of inclination, said imparting step being accomplished by forming a flat surface at the distal end of the ferrule, oriented with respect to the normal plane of the bore at the angle of inclination, and polishing the flat surface into a cylindrical surface, said cylindrical surface having an axis which is parallel with the gradient of the flat surface.
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16. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
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obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; and imparting a spherical end face to the distal end of the ferrule, adjacent the chamfer surface, the spherical end face having a periphery which is inclined with respect to a plane normal to the bore, defining an angle of inclination, the spherical end face further having a tangent at the bore which is parallel with the angle of inclination, said imparting step being accomplished by polishing the ferrule at an angle ψ
=θ
+fθ
, where θ
is the desired angle of inclination and ##EQU8## VR is the starting diameter of the ferrule end face, r is the effective radius of the spherical surface, a is the effective height of the chamfer, and b is the effective width of the chamfer.
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17. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
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obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; forming a flat surface at the distal end of the ferrule, adjacent to the chamfer surface, said flat surface being inclined with respect to a plane normal to said bore, defining an angle of inclination; and convening said flat surface into a spherical surface having a tangent at the bore which is parallel with the angle of inclination, by polishing the flat surface against a compliant pad while maintaining the ferrule at an oblique angle with respect to the pad, the oblique angle being greater than the angle of inclination.
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18. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
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obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; forming a convex surface at the distal end of the ferrule, adjacent to the chamfer surface, said convex surface having a periphery which is inclined with respect to a plane normal to said bore, defining an angle of inclination; and converting said convex surface into a spherical surface having a tangent at the bore which is parallel with the angle of inclination by polishing the convex surface against a compliant pad while maintaining the ferrule at an oblique angle with respect to the pad, the oblique angle being greater than the angle of inclination.
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19. A method of preparing a ferrule for a fiber optic connector, comprising the steps of:
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obtaining a ferrule having a distal end with a chamfer surface, the ferrule also having a central bore for receiving an optical fiber; forming a flat surface at the distal end of the ferrule, adjacent to the chamfer surface, said flat surface being inclined with respect to a plane normal to said bore, defining an angle of inclination; and converting said flat surface into a spherical surface having a tangent at the bore which is parallel with the angle of inclination, by polishing the flat surface into a cylindrical surface, said cylindrical surface having an axis which is parallel with the gradient of the flat surface.
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Specification