Optical waveguides – With optical coupler – Input/output coupler
Reexamination Certificate
2001-12-19
2004-02-03
Stafira, Michael P. (Department: 2877)
Optical waveguides
With optical coupler
Input/output coupler
C385S031000, C385S088000, C385S092000, C385S093000, C359S652000
Reexamination Certificate
active
06687434
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical element, such as a gradient-index rod-lens and a capillary. More particularly, the present invention pertains to an optical element having at least one end surface that is inclined with respect to a central axis of the rod lens or the capillary.
A typical gradient-index rod-lens converts light that is sent from a light source, such as a laser diode and a light emitting diode (LED), to a parallel light or converges light that is received through an optical fiber at a predetermined position- To transmit light from one optical fiber to another, two rod lenses are arranged to contact each other Alternatively, a filter, which has desired optical characteristics, is placed between two rod lenses. The lens length of the rod lens is determined according to the intended purpose of the rod lens. For example, the lens length of the rod lens is set in accordance with the distance between the output end of the optical fiber and the rod lens or the distance between the two rod lenses such that the coupling loss is minimized.
FIG. 6
illustrates conventional rod lenses
60
,
61
used in an optical communication module. The rod lens
60
on the left side has an output side end surface
60
a
, which is inclined with respect to a central axis C
1
of the rod lens
60
. The rod lens
61
on the right side has an input side end surface
61
a
, which is inclined with respect to a central axis C
2
of the rod lens
61
.
An optical fiber
64
is held by a capillary
63
and an optical fiber
66
is held by a capillary
65
. A filter
62
is placed between a distal end portion
60
b
of the rod lens
60
and a distal end portion
61
b
of the rod lens
61
. The rod lens
60
converts light that is emitted from the output end of the optical fiber
64
to a parallel light. The parallel light is transmitted through the filter
62
and enters the rod lens
6
l. The rod lens
61
converges the parallel light at the input end of the optical fiber
66
. The converged light travels through the optical fiber
66
and is sent to another optical element. The two rod lenses
60
,
61
optically couple the two optical fibers
64
,
66
.
The lens length Z of the rod lens
60
is the length of the central axis C
1
between both end surfaces. The lens length Z of the rod lens
61
is the length of the central axis C
2
between both end surfaces. The distance L between the two rod lenses
60
,
61
is the distance between the output side end surface
60
b
and the input side end surface
61
a
along the central axes C
1
, C
2
.
The distal end portions
60
b
,
61
b
of the conventional rod lenses
60
,
61
are sharp and easily damaged. For example, the distal end portions
60
b
,
61
b
could get chipped when placing the filter
62
between the distal end portions
60
b
,
61
b
, or when the distal end portions
60
b
,
61
b
are arranged to contact each other. If the distal end portions
60
b
,
61
b
get chipped, the distance L changes. Therefore, the lens length Z, which is optimized in accordance with the distance L before the distal end portions
60
b
,
61
b
get chipped, is not optimum. Thus, the optical communication module that uses the rod lenses
60
,
61
having chipped distal end portions
60
b
,
61
b
has great coupling loss. Accordingly, the optical fibers
64
,
66
are not optically coupled in the optimum manner. Also, when inserting the rod lenses
60
,
61
into a holder such as a cylindrical sleeve, the sharp distal end portions
60
b
,
61
b
could contact the holder and get chipped. In this case, the optical module is defective. Similar problem occurs when the end surface of each capillary
63
,
65
is inclined. If the sharp distal end portions of the rod lenses
60
,
61
or the capillaries
63
,
65
get chipped, the chipped pieces could further increase the coupling loss.
SUMMARY OF THE INVENTION
The objective of the present invention is to provide an optical element for an optical communication module that is not easily damaged, improves the defect rate, and reduces the coupling loss
The objective of the present invention is to provide an optical element for an optical communication module that minimizes the coupling loss without performing alignment during the assembly of various types of optical modules.
To achieve the foregoing objective, the present invention provides an optical element. The optical element includes a first end surface and a second end surface. At least one of the first end surface and the second end surface includes an inclined surface, which is inclined by a predetermined angle with respect to a central axis of the optical element, and a distal end surface, which is adjacent to the inclined surface.
The present invention also provides a cylindrical optical element. The cylindrical optical element includes a first end surface, a second end surface, and an outer circumferential surface. The first end surface intersects a central axis of the optical element. The second end surface intersects the central axis. The outer circumferential surface extends along the central axis. At least one of the first end surface and the second end surface includes an inclined surface, which is inclined by a predetermined angle with respect to the central axis of the optical element, and a contact surface, which is adjacent to the inclined surface and is perpendicular to the central axis.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings illustrating by way of example the principles of the invention.
REFERENCES:
patent: 4895433 (1990-01-01), Takahashi et al.
patent: 5074682 (1991-12-01), Uno et al.
patent: 5172271 (1992-12-01), Sinclair
patent: 5221839 (1993-06-01), Braun
patent: 5757993 (1998-05-01), Abe
patent: 6055112 (2000-04-01), Campbell-Miller et al.
patent: 6253007 (2001-06-01), Laughlin
patent: 6263133 (2001-07-01), Hamm
patent: 6408115 (2002-06-01), McIntyre
patent: 6445939 (2002-09-01), Swanson et al.
patent: 2002/0094162 (2002-07-01), Li et al.
patent: 2002/0159693 (2002-10-01), Wolak et al.
“SELFOC Product Guide”, Sep. 1993, NSG Europe XP002190689.
Marsh & Fischmann & Breyfogle LLP
Nippon Sheet Glass Co. Ltd.
Stafira Michael P.
Valentin Juan D
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