Optical waveguides – With optical coupler – Input/output coupler
Reexamination Certificate
2002-06-12
2003-07-15
Kim, Ellen E. (Department: 2874)
Optical waveguides
With optical coupler
Input/output coupler
C385S031000, C385S043000
Reexamination Certificate
active
06594419
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention
The invention relates generally to lensed fibers for delivering and collecting light in optical communication networks. More specifically, the invention relates to a tapered lensed fiber for focusing and condenser applications and a method for forming the tapered lensed fiber.
2. Background Art
A lensed fiber is a monolithic device having an optical fiber terminated with a lens. Lensed fibers are advantageous because they are easy to assemble, i.e., they do not require active fiber-lens alignment and gluing of fiber to lens, they have low insertion loss, and they enable component miniaturization because they can be made very small. The coefficient of thermal expansion of the lens can be matched to that of the optical fiber to achieve better performance over a temperature range. Lensed fibers are easily arrayed and are therefore desirable for making arrayed devices, for use in silicon optical bench applications, for aligning optical fibers to planar waveguides, and so forth. In addition, the spot size and working distance of the lensed fiber can be tailored for a specific application. For example, the spot size and working distance can be tailored to produce smaller beam diameters that can allow use of smaller micro-electro-mechanical-systems (MEMS) mirrors in optical switches.
There are three main types of lensed fibers, including collimating lensed fibers, focusing lensed fibers, and tapered lensed fibers.
FIG. 1
shows a prior-art collimating lensed fiber
20
having a planoconvex lens
22
fusion-spliced to one end of an optical fiber
24
. The optical fiber
24
may be a single-mode or multimode fiber. In the illustration, the optical fiber
24
is a single-mode fiber. The planoconvex lens
22
is formed from a coreless fiber, and the front surface of the lens
22
is shaped like a sphere. The spherical surface of the lens
22
is typically formed by melting the coreless fiber using an electric arc or a laser beam. The spherical surface of the lens
22
acts as a collimator, expanding the light coming out of the optical fiber
24
into a collimated beam. In practice, the lensed fiber
20
is used to couple light from one fiber to another.
FIG. 2A
shows a prior-art focusing lensed fiber
26
having a first square-law index fiber
28
fusion-spliced to one end of a single-mode fiber
30
. A second square-law index fiber
32
is connected to the first square-law fiber
28
. A convex surface
34
, which acts as a lens, may be provided at a distal end
36
of the second square-law index fiber
32
. In general, the radius of curvature of the convex surface
34
is smaller than the radius of curvature of the lens for the collimating lensed fiber (see lens
22
in FIG.
1
). The focusing lensed fiber
26
focuses light into a spot and is useful for focusing applications, such as focusing a beam onto a detector or receiver and coupling light from a laser source to an optical fiber.
There are various methods for providing the convex surface
34
at the distal end
36
of the second square-law index fiber
32
. One method involves melting the distal end
36
to form a hemispherical surface. A second method involves chemically etching the distal end
36
to form the convex surface
34
. A third method, which is illustrated in
FIG. 2B
, involves fusion-splicing a coreless fiber
38
to the distal end
36
of the second square-law index fiber
32
and then melting the coreless fiber
38
to form a hemispherical surface. Melting is usually based on electric discharge.
FIG. 3
shows a prior-art tapered lensed fiber
40
having a taper
42
formed at a tip of a single-mode fiber
44
. The taper
42
has a convex surface
46
that acts as a lens. The taper
42
can be achieved by grinding and/or polishing the tip of the single-mode fiber
44
. The tapered lensed fiber collimates light over a short working distance. The tapered lensed fiber can be used for coupling light between an optical fiber and a laser source or an optical amplifier or a planar waveguide.
SUMMARY OF INVENTION
In one aspect, the invention relates to a tapered lensed fiber which comprises a tapered multimode fiber having a gradient-index core and an optical fiber attached to the tapered multimode fiber.
In another aspect, the invention relates to a method for forming a tapered lensed fiber which comprises attaching an optical fiber to a multimode fiber having a gradient-index core, applying heat to a surface of the multimode fiber, and pulling the multimode fiber into a taper.
In another aspect, the invention relates to a method for forming a tapered polarization-maintaining fiber which comprises attaching a polarization-maintaining fiber to a multimode fiber having a gradient-index core, applying heat to a surface of the multimode fiber, and pulling the multimode fiber into a taper.
In another aspect, the invention relates to a tapered polarization-maintaining fiber which comprises a tapered multimode fiber having a gradient-index core and a polarization-maintaining fiber attached to the tapered multimode fiber.
Other features and advantages of the invention will be apparent from the following description and the appended claims.
REFERENCES:
patent: 3832028 (1974-08-01), Kapron
patent: 4186999 (1980-02-01), Harwood et al.
patent: 4281891 (1981-08-01), Shinohara et al.
patent: 4380365 (1983-04-01), Gross
patent: 4456330 (1984-06-01), Bludau
patent: 4496211 (1985-01-01), Daniel
patent: 4542987 (1985-09-01), Hirschfeld
patent: 4737006 (1988-04-01), Warbrick
patent: 4743283 (1988-05-01), Borsuk
patent: 4784466 (1988-11-01), Khoe et al.
patent: 4785824 (1988-11-01), Wickersheim et al.
patent: 4896942 (1990-01-01), Onstott et al.
patent: 5008545 (1991-04-01), Anderson et al.
patent: 5039193 (1991-08-01), Snow et al.
patent: 5551968 (1996-09-01), Pan
patent: 5647041 (1997-07-01), Presby
patent: 5699464 (1997-12-01), Marcuse et al.
patent: 5754717 (1998-05-01), Esch
patent: 5774607 (1998-06-01), Shiraishi et al.
patent: 5908562 (1999-06-01), Ohtsu et al.
patent: 5946441 (1999-08-01), Esch
patent: 6094517 (2000-07-01), Yuuki
patent: 6130972 (2000-10-01), Shiraishi et al.
patent: 6282347 (2001-08-01), Ono et al.
patent: 0 278 212 (1993-09-01), None
patent: WO 00/34810 (2000-06-01), None
Ukrainczyk Ljerka
Vastag Debra L.
Adewuya Adenike A.
Corning Incorporated
Kim Ellen E.
Schaeberle Timothy M.
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