Optics: measuring and testing – By alignment in lateral direction – With light detector
Reexamination Certificate
2002-01-03
2004-11-02
Smith, Zandra V. (Department: 2877)
Optics: measuring and testing
By alignment in lateral direction
With light detector
Reexamination Certificate
active
06813023
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to alignment of optical devices. More particularly this invention relates to apparatus and method for the automatic optical alignment of two linear structures.
2. Description of the Related Art
In the past, the assembly and manufacture of optical assemblies having a linear array of optical elements has been time consuming and prone to quality control problems. The latest developments in optical cross-connect assemblies have only magnified these problems. Precisely engineered optical receiver arrays are required in these assemblies. A general demand for more precisely constructed assemblies having greater reliability has translated into a demand for better manufacturing apparatus and processes.
Optical devices of the type addressed by the present invention currently in use involve an array of optical fibers having light transmitted therethrough. The light exiting the end faces of the fibers is transmitted through a plurality of waveguides, which produce a diffraction pattern. The diffracted light is collimated by focusing optics, and then falls on a detector array.
In order to equalize the signals falling on individual elements of the detector array, it is necessary that the detector array be precisely aligned with respect to the axis of the waveguides and the focusing optics. Optimizing the alignment has heretofore been a tedious, labor intensive process. In some applications the detector array is positioned manually, and adjustment of the input elements is performed using a manual technique. This is because the cross section of the detectors is large enough to permit manual manipulation.
SUMMARY OF THE INVENTION
It is therefore a primary object of some aspects of the present invention to improve the manufacture of optical linear arrangements.
It is another object of some aspects of the present invention to automate the alignment of two linear optical arrangements relative to one another with a high degree of precision.
There is thus provided in accordance with a preferred embodiment of the invention a method of alignment, which includes the steps of:
holding a first optical element in opposition to a second optical element for interalignment therewith, the second optical element including a plurality of receivers including a first marginal receiver and a second marginal receiver, the first optical element having a first axis and a second axis, and the second optical element having a third axis and a fourth axis,
detecting a plurality of light signals that pass from the first optical element to the second optical element, the light signals including a first light signal that impinges on the first marginal receiver, and a second light signal that impinges on the second marginal receiver,
in a first phase of operation the first optical element is rotated about a Y-axis until the second axis is in a parallel alignment with the fourth axis and in a second phase of operation the first optical element is displaced along the Y-axis and
while displacing the first optical element along the Y-axis, recording a signal strength of one of the first light signal and the second light signal and displacing the first optical element along a Z-axis until the signal strength has an optimal value.
There is also provided in accordance with a preferred embodiment of the present invention a computer software product, which includes a computer-readable medium in which program instructions are stored and the program instructions are read by a computer, wherein the computer is connected to an alignment apparatus. The alignment apparatus includes a chuck holding a first optical element thereon, the first optical element opposing a second optical element for interalignment therewith, the second optical element includes a plurality of receivers, which includes a first marginal receiver and a second marginal receiver, the first optical element having a first axis and a second axis, the second optical element having a third axis and a fourth axis, a plurality of detectors, each of the detectors detecting light emitted from the first optical element that impinges on one of the receivers, the detectors include a first detector that detects the light impinging on the first marginal receiver, and a second detector that detects the light impinging on the second marginal receiver, a first actuator for displacing the chuck on a Y-axis, the first actuator being driven by a first motor, a second actuator for displacing the chuck on a Z-axis, the second actuator being driven by a second motor, a third actuator for rotating the chuck about the Y-axis, the third actuator being driven by a third motor, wherein the computer receives a plurality of signals from the detectors, the signals including a first signal from the first detector, a second signal from the second detector, the computer transmitting control signals to energize the first motor, the second motor, and the third motor and the instructions, when read by the computer, causes the computer to perform the steps of: in a first phase of operation, energizing the third motor to rotate the chuck about the Y-axis until the second axis is in a parallel alignment with the fourth axis and in a second phase of operation energizing the first motor to displace the chuck along the Y-axis, while performing the step of energizing the first motor, recording a response of one of the first detector, the second detector and energizing the second motor to displace the chuck along the Z-axis until a first function of the response has an optimal value.
There is further provided in accordance with a preferred embodiment of the present invention an alignment apparatus, which includes a chuck holding a first optical element thereon, the first optical element opposing a second optical element for interalignment therewith, the second optical element including a plurality of receivers including a first marginal receiver and a second marginal receiver, the first optical element having a first axis, the second optical element having a second axis, a plurality of detectors, each of the detectors detecting light emitted from the first optical element that impinges on one of the receivers, the detectors include a first detector that detects the light impinging on the first marginal receiver, and a second detector that detects the light impinging on the second marginal receiver, a first actuator for displacing the chuck on a Y-axis, the first actuator being driven by a first motor, a second actuator for displacing the chuck on a Z-axis, the second actuator being driven by a second motor, a third actuator for rotating the chuck about the Y-axis, the third actuator being driven by a third motor, a computer, receiving a plurality of signals from the detectors, the signals including a first signal from the first detector, a second signal from the second detector, the computer transmitting control signals to energize the first motor, the second motor, and the third motor, computer program instructions being stored in the computer, which instructions. When the instructions are read by the computer, the computer performs the steps of: in a first phase of operation energizing the third motor to rotate the chuck about the Y-axis until the first axis is in a parallel alignment with the second axis and in a second phase of operation energizing the first motor to displace the chuck along the Y-axis. While performing the step of energizing the first motor, recording a response of one of the first detector, the second detector and energizing the second motor to displace the chuck along the Z-axis until a first function of the response has an optimal value.
There is further provided in accordance with yet another preferred embodiment of the present invention an alignment apparatus, which includes a chuck holding a first optical element thereon, the first optical element opposing a second optical element for interalignment therewith, the second optical element being carried on a substrate, the second optical element including a plu
Matmon Guy
Rephaeli Eli
Shekel Eyal
Chiaro Nerwork Ltd.
Ladas & Parry
Smith Zandra V.
Stock, Jr. Gordon J.
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