Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
1999-02-19
2001-08-28
Lee, John D. (Department: 2874)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S137000
Reexamination Certificate
active
06282351
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical module comprising an optical fiber whose cladding surface is coated with carbon, and a method of making the optical module.
2. Related Background Art
Employed in optical modules is a bared optical fiber stripped of a resin coated on the side face thereof, so that the cladding surface is exposed. The bared optical fiber is used in the optical module, while the bared optical fiber is inserted in a ferrule. The ferrule and the optical fiber whose side face is covered with the ferrule are mounted to an optical module substrate.
SUMMARY OF THE INVENTION
Having studied the prior art, the inventor has found the following problems.
When the bared optical fiber is mounted on the optical module substrate, the bared optical fiber is bent within a permissible range of radius of curvature so that no excess bending stress is applied thereto. Since the bared optical fiber is bent within a predetermined range of radius of curvature, the part of bared optical fiber not covered with the ferrule cannot be shortened. Therefore, it has been impossible for the optical module substrate mounted with the bared optical fiber to reduce its size. The size of the optical module substrate has been one factor preventing the optical module from reducing its dimensions.
It is thus an object of the present invention to provide an optical module that can reduce the dimensions thereof, and a method of making the optical module.
The optical module in accordance with the present invention comprises an optical module substrate, a carbon-coated optical fiber, a ferrule, and an optical device. The carbon-coated optical fiber has the outer periphery of its cladding coated with carbon. The coating thickness of carbon is within the range of 0.03 &mgr;m to 0.05 &mgr;m, for example. The optical module substrate has first, second, and third regions along a predetermined axis. This substrate is provided with a ferrule support groove in the first region, an optical fiber support groove in the second region, and a device mount portion in the third region. The carbon-coated optical fiber is mounted on the optical fiber support groove. The side face of the carbon-coated optical fiber is covered with the ferrule. The ferrule is mounted on the ferrule support groove. In the device mount portion, the optical device is placed so as to be optically coupled with the optical fiber.
When the carbon-coated optical fiber is employed as the optical fiber placed on the optical module substrate, then the radius of curvature permitted to the optical fiber in the placement can be lowered. As a result, the part of optical fiber not covered with the ferrule can reduce its length, whereby the optical fiber support groove can be shortened. Hence, the optical module substrate would attain a smaller size.
The ferrule support groove supports the ferrule by two faces thereof, whereas the optical fiber support groove supports the carbon-coated optical fiber by two faces thereof. The device mount portion includes a position marker for determining the position at which the optical device is to be mounted.
The optical module substrate can comprise the ferrule support groove and the optical fiber support groove on the same surface of the optical module substrate. In this case, the optical module substrate is preferably formed from a silicon substrate.
The optical module substrate can have a connection groove formed so as to separate the first region and the second region from each other. The connection groove can have a portion deeper than the ferrule support groove.
The optical module substrate can have a positioning groove formed so as to separate the second region and the third region from each other.
The optical module substrate can have a base having the ferrule support groove and a platform having the optical fiber support groove and the device mount portion. The platform is mounted on the base.
The method of making an optical module comprises the steps of: preparing a substrate having first, second, and third regions placed along a predetermined axis; mounting an optical device on a device mount portion of the substrate; placing a carbon-coated optical fiber in an optical fiber support groove, said carbon-coated optical fiber being inserted and secured to a ferrule; securing an end portion of the carbon-coated optical fiber placed in the optical fiber support groove to the substrate; and placing the ferrule with the carbon-coated optical fiber inserted therein in a ferrule support groove.
If the carbon-coated optical fiber is used, the carbon-coated optical fiber can be bent with a curvature smaller than that permitted in the conventional bared optical fiber when the carbon-coated optical fiber is placed in the optical fiber support groove while bending. The part of the carbon-coated optical fiber extending from the ferrule can be placed in the short optical fiber support groove of the small-sized substrate.
The method of making an optical module can comprise a step of forming the ferrule support groove in the first region, the optical fiber support groove in the second region, and a marker for mounting the optical device in the third region.
This step of forming can have a step of collectively forming the ferrule support groove, optical fiber support groove, and marker along a predetermined axis. The ferrule support groove supports the ferrule by two faces thereof, whereas the optical fiber support groove supports the carbon-coated optical fiber by two faces thereof.
Also, the method can have a step of forming a connection groove that separates the first region and the second region from each other and intersects the predetermined axis.
Further, the method can have a step of forming a positioning groove that separates the second region and the third region from each other and extends in a direction intersecting the predetermined axis. The positioning groove can be used to define the position of an end portion of the carbon-coated optical fiber.
The step of securing has a step of providing a UV curing resin between the substrate and a securing member which is ultraviolet(UV)-transparent, and a step of irradiating the UV-curing resin with ultraviolet ray so as to cure the UV-curing resin. Using the UV-transparent securing member and the UV-curing resin makes it easier to position the optical fiber with respect to the substrate and secure the optical fiber to the substrate.
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Go Hisao
Yoneyama Shunichi
Connelly-Cushwa Michelle R.
Lee John D.
McDermott & Will & Emery
Sumitomo Electric Industries Ltd.
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