Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
2000-10-06
2003-04-01
Epps, Georgia (Department: 2873)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S088000
Reexamination Certificate
active
06540413
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a fiber-optic transmitting component in which, by means of an internal polarization filter, a defined proportion of the light output emitted by a light-emitting device can be set precisely and coupled into an optical fiber.
A specific class of fiber-optic transmitting components has a light-emitting component, a tubular or cylindrically shaped housing surrounding the component, and an adjusting sleeve that is fixed to the housing on the light output side. An optical fiber can be inserted and fixed in a suitable manner into the adjusting sleeve at its end facing away from the housing. Such a fiber-optic transmitting component is also referred to as a receptacle laser. The light-emitting device generally includes a semiconductor laser and optical elements, such as prisms and at least one lens, by means of which the beam of radiation emitted by the semiconductor laser can be deflected and focused onto the input end of the optical fiber fixed in the adjusting sleeve. By contrast, other fiber-optic transmitting components, specifically so-called pigtail lasers, do not have an adjusting sleeve but a fiber flange which includes a central passage opening in which an optical fiber is permanently mounted.
In the case of these fiber-optic transmitting elements, it is often desirable to ensure, during the manufacture, that only a defined proportion of the light output emitted by the light-emitting component is coupled into the optical fiber. However, without an adjustable distance between the optical fiber and the respective light-emitting component, it is very difficult or virtually impossible to set a defined, preselected input coupling level into the optical fiber during the adjusting stage, because a large number of variables determines this input coupling. Hitherto, in the case of receptacle lasers this problem has been solved by the light-emitting components, that is to say generally the semiconductor lasers, being measured and selected with regard to their emission characteristics (focal point, squint angle) and emitted power. For the purpose of the adjustment, the characteristic laser diode is assigned a suitable adjusting sleeve with the appropriate length to the fiber stop. Given the tolerances which occur in this case and which add up in each case, the respective input coupling can be set only over a wide tolerance band. The components with the desired input coupling then have to be selected by means of a measurement with a correspondingly low yield if a specific input coupling window is required in the application. In addition, a high logistical outlay for keeping stocks of different adjusting sleeves is necessary.
In order to make it possible to set the input coupling during the adjustment, some manufacturers use an additional connecting element (additional sleeve) and set the input coupling by means of axial displacement of the fiber guide. This is consequently possible only with an additional adjustment process and with the abovementioned additional sleeve as an additional mounting element. This impairs the overall mechanical stability of the component and increases the total manufacturing costs of the component as a result of the additional adjustment step and the additional mounting element.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a fiber-optic transmitting component and a method for its assembly, which overcomes the above-mentioned disadvantages of the heretofore known devices and methods of this general type in which, during manufacture, it is possible to set a defined input coupling of the light output emitted by a light-emitting device into an optical fiber in a purposeful, precise manner and without any increased expenditure on adjustment, manufacture and costs.
With the foregoing and other objects in view there is provided, in accordance with the invention, a fiber-optic transmitting component from the class of receptacle lasers, having a light-emitting device, which is surrounded by a housing, and an adjusting sleeve which, at its one end, is connected to the housing and extends in the direction of a main emission direction of the beam of radiation emerging from the housing from the light-emitting device, and, at its other end, an optical fiber can be inserted and fixed in such a way that the beam of radiation can be coupled into the optical fiber, the adjusting sleeve having, at its one end, a base plate with a central opening, and a polarization filter that covers the opening being fixed indirectly or directly to the base plate.
In accordance with another object of the invention, there is provided a fiber-optic transmitting element from the classes of pigtail lasers, in which, instead of the aforementioned adjusting sleeve, a fiber flange is connected at its one surface to the housing and, at its other surface, an optical fiber is fixed in a central opening in the fiber flange in such a way that a beam of radiation emerging from the housing from the light-emitting device can be coupled into the optical fiber.
Accordingly, the fiber flange is shaped like the aforementioned base plate of an adjusting sleeve, but an optical fiber is permanently mounted in the central opening.
When setting the proportion of the light output that is coupled into the optical fiber, use is therefore made of the fact that the light-emitting device contains a semiconductor laser which emits a beam of radiation with a defined direction of polarization. The angular position of the polarization filter therefore determines the transmitted proportion of the beam of radiation through the polarization filter, and therefore the proportion of the radiation coupled into the optical fiber.
In accordance with an added object of the invention, there is provided a method of assembling a fiber-optic transmitting component. This method is based on the fact that the laser housing and the adjusting sleeve or the fiber flange with the polarization filter fixed to it are available as separate components and are then fixed to each other.
The method of assembling a fiber-optic transmitting component on the basis of the receptacle laser has the following method steps: manufacturing the light-emitting component and installing it in the housing; manufacturing the adjusting sleeve and fixing the polarization filter to the base plate of the sleeve; starting up the light-emitting device and aligning the adjusting sleeve axially with the main emission direction of the light-emitting device with the fiber plugged into the adjusting sleeve; measuring the light output of the optical radiation that has passed through the polarization filter in the glass fiber that is plugged in, as a function of an axial angular position of the adjusting sleeve; and fixing the adjusting sleeve to the housing at an axial angular position as soon as the light output assumes a previously determined value at this axial angular position.
The method of assembling a fiber-optic transmitting component on the basis of the pigtail laser differs from the abovementioned method in the fact that, instead of the adjusting sleeve, a fiber flange is manufactured, an optical fiber is mounted in the central opening of the fiber flange and a polarization filter that covers the central opening is fixed to the surface facing the light-emitting device.
It is preferable for the housing and the adjusting sleeve or the fiber flange to be cylindrically symmetrical, and for the axes of the cylinders and the main emission direction to coincide. An embodiment which is practical for fixing the housing and the adjusting sleeve consists in the housing and the adjusting sleeve each having a mounting flange, that is to say a fixing face that extends in the radial direction over the entire periphery and at which they can be fixed to each other. During the alignment and adjustment operation, the two components can be placed against each other at their mounting flanges and rotated in relation to each other until the desired light output has been achie
Althaus Hans Ludwig
Hartl Alfred
Reill Joachim
Epps Georgia
Greenberg Laurence A.
Hanig Richard
Infineon - Technologies AG
Locher Ralph E.
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