Optical fiber polishing system with depth reference
First Claim
1. A system for polishing an optical fiber with a polishing lap, comprising:
- a substrate;
an elongate optical fiber disposed on the substrate so as to be outwardly curved;
an electrical conductor disposed over the outward curve of the optical fiber;
a voltage source connected to the electrical conductor for supplying a voltage thereto;
wherein the polishing lap is configured to initially abrade the electrical conductor to cause severance thereof, the position of the polishing lap when the electrical conductor is severed representing a reference point relative to the surface of the optical fiber;
a detector configured for detecting a change in voltage in the electrical conductor, said change being indicative of the severance of the electrical conductor, and for monitoring the polishing depth relative to the reference point.
1 Assignment
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Accused Products
Abstract
A system and method for polishing an optical fiber with a polishing lap. The system comprises a substrate, an optical fiber disposed on the substrate so as to be outwardly curved, and an electrical conductor disposed over the outward curve of the optical fiber. A voltage source is connected to the electrical conductor, and the polishing lap is configured to initially abrade the electrical conductor to cause severance thereof. The position of the polishing lap when the electrical conductor is severed represents a reference point approximately indicating the surface of the optical fiber. A detector connected to the electrical conductor detects a change in voltage therein, indicating severance of the electrical conductor, and subsequently monitors the polishing depth relative to the reference point.
20 Citations
20 Claims
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1. A system for polishing an optical fiber with a polishing lap, comprising:
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a substrate;
an elongate optical fiber disposed on the substrate so as to be outwardly curved;
an electrical conductor disposed over the outward curve of the optical fiber;
a voltage source connected to the electrical conductor for supplying a voltage thereto;
wherein the polishing lap is configured to initially abrade the electrical conductor to cause severance thereof, the position of the polishing lap when the electrical conductor is severed representing a reference point relative to the surface of the optical fiber;
a detector configured for detecting a change in voltage in the electrical conductor, said change being indicative of the severance of the electrical conductor, and for monitoring the polishing depth relative to the reference point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
a top surface;
a first groove formed in the top surface, the first groove sized to allow insertion of a portion of the optical fiber therein, and further having an outwardly curved bottom surface configured to cause the portion of the optical fiber disposed therein to curve outwardly, such that a side of the fiber is approximately tangent to the top surface of the substrate; and
a second groove formed in the top surface and oriented substantially perpendicular to the first groove, the second groove sized to allow insertion of a portion of the electrical conductor therein, said portion of the electrical conductor extending out of the second groove and overlying the outward curve of the optical fiber approximately at its point of tangency to the top surface.
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4. The system of claim 3, wherein the substrate comprises fused silica.
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5. The system of claim 1, wherein the polishing lap comprises a rotary lapping machine having:
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a horizontal rotating platen with an abrasive surface;
a polishing solution delivery conduit for supplying a constant flow of polishing solution to the surface of the platen;
a moveable arm disposed adjacent to the platen, configured to receive the substrate with the optical fiber and the electrical conductor disposed thereon, attached to a distal end of the moveable arm, and to move up and down relative to the abrasive surface, so as to press the electrical conductor, optical fiber and substrate against the abrasive surface of the platen.
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6. The system of claim 5, wherein the abrasive surface is selected from a group consisting of:
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a first pad, comprising diamond grit;
and, a second pad, comprising one of two materials consisting of felt and expanded polyurethane, said second pad being provided with a slurry of at least one of cesium oxide and colloidal silica.
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7. The system of claim 1, wherein the detector further comprises:
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a digital interface electrically connected to the electrical conductor, and configured for converting an analog signal to a digital signal; and
a computer connected to the digital interface and the polishing lap, and configured for receiving signals from the digital interface, and for controlling the functioning of the polishing lap in response thereto.
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8. The system of claim 1, further comprising a depth sensor configured for sensing the depth of polishing of the optical fiber relative to the reference point.
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9. The system of claim 8, wherein the depth sensor comprises an optical probe.
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10. A system for controlling the depth to which a movable polishing lap polishes an optical fiber, comprising:
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an optical fiber, disposed upon a substrate, the fiber having a curved portion which extends toward a top surface of the substrate;
an electrical conductor disposed over an apex of the curve of the optical fiber;
a voltage source connected to the electrical conductor, for supplying a voltage thereto; and
a detector, further comprising;
a digital interface connected to the electrical conductor, and configured for converting an analog signal in the electrical conductor to a digital output signal; and
a computer connected to the digital interface, for receiving the output signal therefrom, and for controlling the polishing lap, whereby the polishing lap may be caused to operably impinge upon and sequentially grind away the electrical conductor and the optical fiber until a sudden change in the voltage in the electrical conductor is detected, said voltage change indicating severance of the electrical conductor, the position of the polishing lap when severence of the electrical conductor is detected providing a reference point relative to the surface of the optical fiber for controlling the depth of continued polishing. - View Dependent Claims (11, 12, 13, 14, 15)
a first groove formed in the top surface thereof, the first groove configured for receiving the optical fiber therein, and further having an outwardly curved bottom surface configured to cause a portion of the optical fiber to be outwardly curved substantially tangential to the top surface of the substrate; and
a second groove formed in the top surface, and oriented substantially perpendicular to the first groove, the second groove configured to receive a portion of the electrical conductor therein, the electrical conductor overlying the outward curve of the optical fiber near the point of tangency thereof to the top surface.
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12. The system of claim 10, wherein the substrate comprises fused silica.
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13. The system of claim 10, wherein the electrical conductor is selected from a group comprising:
- a wire; and
a stripe of electrically conductive material applied to the optical fiber.
- a wire; and
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14. The system of claim 10, wherein the polishing lap comprises a rotary lapping machine having:
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a horizontal rotating platen with an abrasive surface;
a polishing solution delivery conduit for supplying a constant flow of polishing solution to the surface of the platen;
a moveable arm disposed adjacent to the platen, configured to receive the substrate with the optical fiber and the electrical conductor disposed thereon, attached to a distal end of the moveable arm, and to move up and down relative to the abrasive surface, so as to press the electrical conductor, optical fiber and substrate against the platen.
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15. The system of claim 14, further comprising an optical probe associated with the moveable arm, and configured for detecting changes in displacement of the distal end of the moveable arm from the reference point, such that the computer may continuously monitor the depth of polishing and send a signal to the polishing lap and moveable arm to discontinue polishing when the desired depth of polishing is reached.
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16. A method for controlling a depth to which a polishing lap polishes an optical fiber, comprising the steps of:
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(a) placing a length of an optical fiber upon a substrate, such that a portion of the optical fiber assumes an outwardly curved shape relative to a top surface of the substrate;
(b) disposing an electrical conductor over an apex of the curved portion of the optical fiber;
(c) connecting the electrical conductor to a voltage source;
(d) moving the substrate toward the polishing lap so as to first press the electrical conductor against a moving abrasive surface of the polishing lap;
(e) polishing the electrical conductor until it severs;
(f) detecting severance of the electrical conductor by detecting a change in voltage therein;
(g) detecting the position of the fiber relative to the polishing lap when said severance is detected, said position being a reference point; and
(h) progressively polishing the curved portion of the optical fiber from the reference point to a desired depth. - View Dependent Claims (17, 18, 19, 20)
(i) forming a first groove in the top surface of the substrate, the first groove sized to allow insertion of a portion of the optical fiber therein, the groove being configured to cause the portion of the optical fiber disposed therein to curve toward the top surface of the substrate; and
(j) forming a second groove in the top surface of the substrate, the second groove oriented substantially perpendicular to the first groove, and sized to allow insertion of a portion of the electrical conductor therein, said second groove configured to coincide with a point of tangency of the curve of the optical fiber to the top surface.
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18. The method of claim 17, further comprising the step of cementing the optical fiber into the first groove.
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19. The method of claim 16, where in the step of disposing an electrical conductor over the curved portion of the optical fiber comprises a step selected from a group comprising:
- placing a wire over the fiber approximately at a point of tangency of the fiber to the top surface; and
applying a stripe of electrically conductive material to the optical fiber at its point of tangency to the top surface.
- placing a wire over the fiber approximately at a point of tangency of the fiber to the top surface; and
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20. The method of claim 16, wherein the voltage source comprises a DC voltage source, and wherein:
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(i) the step of detecting severance of the electrical conductor comprises detecting a change in the DC voltage in the electrical conductor with a digital input/output device connected to a computer, and sending a signal to the computer indicating the change in DC voltage; and
(j) the step of detecting the position of the substrate when severance is detected further comprises the step of providing an optical probe depth sensor indicating the position of the fiber at the time of the voltage change.
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Specification