Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
2001-10-30
2003-05-27
Palmer, Phan T. H. (Department: 2874)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S090000, C385S092000, C385S014000
Reexamination Certificate
active
06568862
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a coupling device for connecting an optical fiber to an optical transmitting or receiving unit and transmitting or receiving device having a coupling device. More specifically, the invention relates to a coupling device for coupling an optical fiber to an optical transmitting or receiving unit, in particular a laser diode. The coupling device has a main section with an accommodation opening to accommodate an optical fiber, and a section projecting like a step and having a flattened surface for fixing the transmitting or receiving unit. In addition, the invention relates to a transmitting or receiving unit having such a coupling device.
Janssen (U.S. Pat. No. 4,874,217) discloses a device for coupling a laser chip to an optical fiber. In this case, a hollow cylinder is adjoined by a semi-cylindrical projection that is fixed to it and on whose flattened side there is a plate-like platform to accommodate the laser chip. The optical fiber, whose end section is constructed as a taper, is disposed in a continuous opening in the long side of the hollow cylinder. The hollow cylinder has longitudinal and transverse incisions in the area of the projection, in order to make the latter deformable for adjusting the laser chip. The hollow cylinder and a further external sleeve of the hollow cylinder are made of metal, and the plate-like platform is produced substantially from diamond.
The drawbacks with the known device are a complex construction and the requirement for active adjustment, which is accomplished by deforming the semi-cylindrical projection. Because of the use of a taper at the end of the fiber, the active adjustment has to be conducted in this case with low tolerance. Adjustment errors in the light propagation direction on the order of magnitude of one micrometer (1 &mgr;m) already have the effect of considerable coupling losses in optical fibers having a taper. Separate positioning elements that contribute further to a complicated construction of the known device are necessary for the deformation of the semi-cylindrical projection necessary for the adjustment and for the fixing of an optimum adjustment.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a coupling device for connecting an optical fiber to an optical transmitting or receiving unit and transmitting or receiving device having a coupling device that overcome the herein-aforementioned disadvantages of the heretofore-known devices of this general type by coupling an optical fiber to a transmitting or receiving unit with a simple construction while being produced cost-effectively and with reduced effort.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a coupling device for coupling an optical fiber to an optical transmitting or receiving unit. The coupling device includes a main section with an accommodation opening for accommodating an optical fiber. A section is formed in one piece with the main section from nonconductive material, projects like a step, and has a flattened surface for directly mounting the transmitting or receiving unit. The optical transmitting or receiving unit projects like a step or a contact-making surface applied to the flattened surface. The flattened surface of the section projects like a step having a longitudinal notch for positioning the transmitting or receiving unit.
Consequently, according to the invention, a single-piece coupling device is provided which includes an electrically insulating material and in which the optical transmitting or receiving unit can be mounted directly on a portion projecting like a step or a contact-making surface applied to the latter.
The elements to be connected with an optical coupling are therefore mounted directly on a single-piece component. Separate components or additional electrical insulators can be omitted. The outlay on material and the overall size of the device are reduced considerably as compared with the prior art.
In addition, the flattened surface of the section projecting like a step has, according to the invention, a longitudinal notch, which is used for positioning the transmitting or receiving unit. The longitudinal notch passively aligns the transmitting or receiving element. Corresponding structures belonging to a transmitting or receiving element engage the longitudinal notch. Appropriate structuring is accomplished, for example, by etching, by grinding or by laser machining.
The passive alignment and centering of the transmitting and receiving component dispenses with the requirement for active adjustment transversely with respect to the longitudinal axis of the device. The transmitting or receiving element to be mounted is positioned automatically when it is placed on the projecting section.
In a preferred embodiment, the flattened surface of the section projecting like a step is located in a plane that intersects the extension of the accommodating opening in the main section. The longitudinal notch represents the continuation of the accommodation opening in the projecting section. The longitudinal axis is therefore produced automatically during the production of the device: it is the remaining part of the continuous accommodation opening in the main section. The material present above the (subsequently) projecting section is removed during the production. In this configuration, the longitudinal notch is produced in a very effective way by using structures that are already present.
In this embodiment, the flattened surface of the section projecting like a step merely must lie in one plane that intersects the extension of the accommodation opening of the main section. In this case, provision may be made for the accommodation opening to be intersected above or below its center. Depending on this, the longitudinal notch has a different width and depth.
In one embodiment, the accommodation opening is intersected not quite at its center, so that the axis of an optical fiber guided in the accommodation opening does not lie in the plane of the surface of the projecting section, which could make coupling light into or out of the optical fiber more difficult, depending on the construction.
In a preferred configuration, the section projecting like a step adjoins the main section rigidly, that is to say substantially without incisions or cutouts. The rigid connection of the section projecting like a step to the main section has the advantage that, after the transmitting or receiving unit has been fixed to the projecting section, there is defined positioning with respect to an optical fiber to be coupled on.
The step-like section preferably forms a vertical stop for the transmitting or receiving element. Positioning in the z-direction as it is placed on the step-like area therefore takes place directly via the surface formed by the step-like section.
In a preferred development of the invention, the section projecting like a step has a structured metallization. The metallization is here structured in as much as only specific structured areas are provided with a metallization, rather than the entire area of the step-like section. In particular, the structured metallization encompasses conductor tracks for making contact with the transmitting or receiving element. The structured metallization is used in particular to make electrical contact with the transmitting or receiving unit. However, it can likewise be used for fixing the transmitting or receiving unit on the projecting section, for example by soldering or bonding.
In a development of the invention, the area projecting like a step has depressions to accommodate fixers and/or contact-makers for the transmitting or receiving element. These depressions are produced, for example, by grinding or milling the projecting section. They mechanically fix the transmitting or receiving unit independently of the step of positioning the transmitting or receiving element.
In this case, for example, a material that performs the joining or fixing of
Kropp Jörg
Schulz Klaus
Stephan Jens
Greenberg Laurence A.
Infineon - Technologies AG
Mayback Gregory L.
Palmer Phan T. H.
Stemer Werner H.
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