Lens function-including optical fiber and method of producing the same
AssigneeNippon Sheet Glass Co., Ltd.
InventorsShigeo Kittaka, Tadashi Koyama, Masami Kitano
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Abstract
A lens function-including optical lens according to the present invention is constituted by: at least one step-index optical fiber; and at least one gradient index optical fiber having an outer diameter equal to that of the step-index optical fiber and having a periodic length exhibiting a lens function, the gradient index optical fiber being joined or attached to an end surface of the step-index optical fiber. The present invention is especially effective in a single mode optical fiber which is typical of the step-index optical fiber. The gradient index optical fiber can be produced by an ion exchange method.
Claims11
A lens function-including optical fiber comprising:
- at least one information transmission optical fiber;
- and
- at least one gradient index optical fiber having an outer diameter equal to that of said information transmission optical fiber and having a length exhibiting a specific lens function, said gradient index optical fiber being jointed or contacted with an end surface of said information transmission optical fiber,
- and wherein, when a refractive-index distribution of said gradient index optical fiber in a wavelength range used is given by the expression:
- n(r)2=n02·{1−(g·r)2+h4(g·r)4+h6(g·r)6+h8(g·r)8+ . . . },
- said gradient index optical fiber satisfies a condition:
- 0.1≦n0·g·r0≦0.5 in which r is a distance from an optical axis, n(r) is a refractive index in a position at the distance r from the optical axis, n0 is a refractive index on the optical axis, r0 is a radius of said gradient index optical fiber, g is a refractive-index distribution coefficient, and h4, h6, h8 . . . are high-order refractive-index distribution coefficients respectively.
A lens function-including optical fiber comprising:
- at least one information transmission optical fiber;
- and
- at least one gradient index optical fiber having an outer diameter equal to that of said information transmission optical fiber and having a length exhibiting a specific lens function, said gradient index optical fiber being jointed or contacted with an end surface of said information transmission optical fiber,
- wherein said information transmission optical fiber and said gradient index optical fiber are joined and fixed to each other in a groove which is formed in a planar substrate and which is V-shaped in section.
A method of producing a lens function 13 including optical fiber, comprising the steps of:
- immersing a homogeneous glass rod in molten salt to perform ion exchange to thereby form a refractive-index distribution in said glass rod;
- forming a gradient index optical fiber with a desired outer diameter by stretching said glass rod while heating said glass rod retained vertically;
- and
- cutting said gradient index optical fiber into a length corresponding to a specific periodic length of said gradient index optical fiber.
Dependencies are inferred from the claim text.