Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
1998-05-20
2001-01-30
Schuberg, Darren (Department: 2872)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S066000, C385S078000
Reexamination Certificate
active
06179483
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a coupling apparatus (receptacle) of a light emitting element such as a laser diode and an optical fiber. The present invention also relates to a method for adjusting optical fiber position using the same.
2. Description of the Related Art
Recently, laser drawing apparatuses using multi-laser beams have been proposed in which a group of light sources consisting of a plurality of laser emitters and a plurality of optical fibers are provided to increase the drawing speed.
In a multi-laser beam drawing apparatus using optical fibers as a light source, the laser beam emitted from the semiconductor laser and made incident upon the incident surface of the optical fiber is partly reflected by the incident surface. If the reflected light is made incident upon the semiconductor laser, the laser emission is disturbed, thus resulting in a change in the intensity of the laser beams, etc. To avoid this, the incident surface of the optical fiber is cut along a plane inclined with respect to the center axis of the optical fiber to form an oblique incident surface, so that the light reflected thereby does not reach the semiconductor laser, as shown in FIG.
4
.
In the prior art shown in
FIG. 4
, a laser diode (LD)
156
is secured to a lens holder
116
which holds a coupling lens
136
through an LD holder
126
. The lens holder
116
is provided with an adjusting ring
166
secured thereto. The optical fiber
20
is held by a ferrule
196
so that the center axis of the optical fiber at the incident surface thereof is inclined with respect to the optical axis of the coupling lens
136
at a predetermined inclination angle. The ferrule
196
is press-fitted in the adjusting ring
166
which is secured to the lens holder
116
. The incident surface of the optical fiber
20
is defined by an oblique surface
20
a
inclined at a predetermined inclination angle with respect to a plane perpendicular to the center axis thereof. The optical fiber
20
is held in such a way that the incident surface
20
a
thereof is not normal to the optical axis O
1
.
The ferrule
196
which holds the optical fiber
20
is not parallel with the optical axis O
1
of the coupling lens
136
and is moved in the direction parallel with the center axis of the optical fiber
20
to adjust the position of the incident surface (core surface)
20
a
of the optical fiber
20
. However, since the direction of the movement of the optical fiber
20
is inclined with respect to the optical axis O
1
, if the ferrule
196
is slid to move the incident surface
20
a
to the focal point of the coupling lens
136
, not only does the distance between the incident surface
20
a
and the coupling lens
136
in the optical axis direction change, but also the distance between the center of the incident surface
20
a
and the optical axis O
1
also varies. Consequently, it is difficult to adjust the incident surface
20
a
of the optical fiber
20
to the focal point f of the coupling lens
136
.
Moreover, to establish a highly precise positional relationship between the laser diode
156
and the optical fiber
20
at the connection therebetween, the LD holder
126
and the adjusting ring
166
are independently moved along the contact surfaces thereof with the lens holder
116
in the prior art. Upon completion of the adjustment, the LD holder
126
and the adjusting ring
166
are welded to the coupling lens holder
116
, for example, by a YAG laser to prevent the accidental movement thereof. Therefore, if the laser diode
156
is broken, it is difficult to replace the laser diode alone. Upon replacement of the broken LD
156
, if the LD holder
126
is detached from the lens holder
116
without detaching the adjusting ring
166
to which the ferrule
196
and the optical fiber
20
are secured from the lens holder
116
, it is difficult to readjust the position of the incident surface
20
a
of the optical fiber
20
, as mentioned above.
The emission surfaces of the light sources are united in the form of a fiber array. Therefore, if a laser diode of one of the light sources is broken, it is difficult to repair or replace the LD since the laser receptacle cannot be disassembled. Furthermore, since the fiber array cannot be disassembled, the entirety of the laser sources must be replaced in spite of the fact that the remaining fibers are normal.
It is possible to secure the adjusting ring
166
to the lens holder
116
by means of screws in place of welding. However, the relative position therebetween may be changed due to the force produced in the rotation direction or forward movement direction of the screws when the screws are fastened or loosened.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a coupling apparatus for a light emitting element and an optical fiber in which the position of the optical fiber can be easily adjusted during the assembling operation.
Another object of the present invention is to provide a simple coupling apparatus of a light emitting element and an optical fiber in which the assembling and disassembling thereof can be easily carried out.
According to an aspect of the present invention, there is provided a coupling apparatus for coupling a holder, to which the light emitting element and a coupling lens are secured, with the optical fiber. This coupling apparatus includes a ferrule which holds the optical fiber and is inclined at a predetermined angle with respect to the optical axis of the coupling lens. Preferably, the incident end surface of the optical fiber is inclined at a predetermined angle with respect to a plane that is normal to the optical axis of the coupling lens.
Also provided is a support member that includes: an adjustable ring which is movable and adjustable in a plane perpendicular to the optical axis of the coupling lens and which is secured to the lens holder; a ferrule ring supported within the adjusting ring, wherein the ferrule ring is movable in a direction parallel with the optical axis of the coupling lens; and a ferrule holder which is detachably press-fitted into the ferrule ring so as to be movable in a direction parallel with the optical axis of the coupling lens. The ferrule is held by the ferrule holder at an inclined position with respect to the optical axis and is movable together with the ferrule holder in a direction parallel with the optical axis.
Alternatively, the support member can include: an adjustable ring which is movable and adjustable in a plane perpendicular to the optical axis of the coupling lens and which is secured to the lens holder; a ferrule ring supported within the adjusting ring, wherein the ferrule ring is movable in a direction parallel with the optical axis of the coupling lens; and wherein the ferrule is held in the ferrule ring at an inclined position with respect to the optical axis and is movable together with the ferrule ring in a direction parallel with the optical axis. The ferrule holder and the adjusting ring can be made of metal and can be secured to the lens holder by laser welding. Alternatively, the ferrule holder is made of metal and the adjusting ring is made of a ceramic material, so that the ferrule holder and the adjusting ring are secured to each other by an adhesive.
According to another aspect of the present invention, there is provided a coupling apparatus for a light emitting element and an optical fiber which includes: a lens holder to which the light emitting element, a coupling lens and the optical fiber are to be secured; an adjusting ring which is movable and adjustable in a plane perpendicular to the optical axis of the coupling lens and which is secured to the lens holder upon completion of the positional adjustment between the adjusting ring and the lens holder; a ferrule ring which is fitted inside the adjusting ring, movable in a direction parallel with the optical axis of the coupling lens and which is secured to the adjusting ring upon completion of positional adjustment between the ferrule ring
Asahi Kogaku Kogyo Kabushiki Kaisha
Pitney Hardin Kipp & Szuch LLP
Schuberg Darren
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