Optical fiber power tap
First Claim
1. An arrangement for tapping optical power from an intermediate portion of an optical fiber waveguide without requiring that the fiber be terminated or broken, said fiber including a guiding region in which the optical power is essentially confined, and including a cladding medium surrounding said guiding region, said arrangement being characterized bya first body of dielectric material having a first major surface disposed in a coupling relationship to an intermediate length of said fiber to couple optical power out of said guiding region of said fiber, said first body having an index of refraction which is approximately equal to or greater than the index of refraction of the medium surrounding said guiding region of said fiber and is selected to couple only a minor portion of the optical power propagating in said fiber waveguide guiding region toward a surface of said dielectric body laterally offset from said guiding region, the material of said first body being substantially more compliant than the material of said fiber;
- adjustable means for pressing said fiber against said first body to provide an area of contact between said first surface of said first body and said intermediate length of said fiber, comprising a second body of dielectric material having an index of refraction less than that of said first body; and
a photodetector contacting said laterally offset surface of said dielectric body and including an active area responsive to the wavelength of the optical signal to be propagated through said fiber, said active area of said photodetector being oriented to intercept the optical power coupled out of said guiding region of said fiber by said first body.
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Accused Products
Abstract
There is disclosed an arrangement for tapping signal power from an optical fiber waveguide without requiring that the fiber be terminated or broken. An intermediate length of a fiber waveguide from which all or most of the outer cladding has been removed is sandwiched between first and second dielectric bodies, each illustratively in the form of a circular disk. The first body, which serves to couple optical power out of the fiber, is formed of a relatively compliant dielectric material, such as a soft plastic, having an index of refraction approximately equal to, or greater than, that of the outer cladding of the fiber. The second body is formed of a relatively hard dielectric material, such as a glass or hard plastic, having an index of refraction less than that of the first body. The two dielectric bodies and the fiber are placed in a specially designed holder and forced together so that the fiber deforms the first body providing a large area of contact therewith. A photodetector disposed adjacent to the first body detects the power coupled out of the fiber, converting it to a representative electrical signal suitable for utilization. The holder serves to maintain the proper pressure and alignment among the two dielectric bodies, the fiber and the photodetector during the tapping process. In a modified embodiment of the fiber tap, the second dielectric body is provided with a rounded surface which forces the fiber to bend into a radius sufficient to cause power to radiate out of the inner core of the fiber into the outer cladding. The latter embodiment can thus tap optical power from a clad fiber without requiring that all or most of the fiber cladding be removed therefrom in the vicinity of the tap.
51 Citations
11 Claims
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1. An arrangement for tapping optical power from an intermediate portion of an optical fiber waveguide without requiring that the fiber be terminated or broken, said fiber including a guiding region in which the optical power is essentially confined, and including a cladding medium surrounding said guiding region, said arrangement being characterized by
a first body of dielectric material having a first major surface disposed in a coupling relationship to an intermediate length of said fiber to couple optical power out of said guiding region of said fiber, said first body having an index of refraction which is approximately equal to or greater than the index of refraction of the medium surrounding said guiding region of said fiber and is selected to couple only a minor portion of the optical power propagating in said fiber waveguide guiding region toward a surface of said dielectric body laterally offset from said guiding region, the material of said first body being substantially more compliant than the material of said fiber; -
adjustable means for pressing said fiber against said first body to provide an area of contact between said first surface of said first body and said intermediate length of said fiber, comprising a second body of dielectric material having an index of refraction less than that of said first body; and a photodetector contacting said laterally offset surface of said dielectric body and including an active area responsive to the wavelength of the optical signal to be propagated through said fiber, said active area of said photodetector being oriented to intercept the optical power coupled out of said guiding region of said fiber by said first body. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification