JPH03197906A - Method for adjusting optical axis of optical signal reception module - Google Patents

Abstract

PURPOSE:To allow the easy, simple and rapid adjustment of a gap by disposing an optical system of a microminiature type connected to a monitor camera into a package and monitoring the gap from the lateral in such a manner that the gap corresponds diametrically to the length of the optical path connecting the light exit part of an optical fiber and the light incident part of a photodetector. CONSTITUTION:The optical axis adjusting device fully automatically adjusts the optical axis by monitoring the gap (optical path length) of the photodetector 2 fixed in the inside bottom of the package 1 and the optical fiber 2 from the lateral so as to adjust the gap. The optical fiber 3 is moved in its longitudinal direction and the photodetecting surface direction of the photodetector 2 by a computer 9, etc., to the prescribed initial position from the image data obtd. by monitoring the optical fiber 3 and the photodetector 2 from the lateral. The gap adjustment in a direction Z is executed by monitoring the gap from the lateral and adjusting the gap to the optimum length so as to diametrically correspond to the above-mentioned length. The accuracy is, therefore, excellent. Since the operation is simple and easy, the efficiency of the adjusting operation is improved overall. The reliability of the optical axis adjusting operation of the optical signal reception module is greatly improved.

Description

[Detailed Description of the Invention] [Summary] An object of the present invention is to provide an optical axis adjustment method for an optical receiving module, which allows adjustment work to be performed accurately and quickly without any particular inconveniences of conventional methods. For the purpose of
An optical axis adjusting means is inserted through the side wall of the package so as to be substantially parallel to the light receiving surface of the light receiving element fixedly installed in the package, and the optical axis adjustment means is configured to convert the optical path direction so that the light emitted from the optical fiber can enter the light receiving element. In an optical receiving module that adjusts the optical axis of an optical fiber and a light receiving element through a The length of the optical path connecting to the light incidence section is monitored from the side so as to be directly opposite to the length of the optical path, so that the length of the optical path becomes an optimum length.

[Industrial application field]

In the present invention, an optical fiber having a slope for changing the direction of the optical path at its tip is inserted through the side wall of the package so as to be substantially parallel to the light receiving surface of a light receiving element fixed in the package, and the direction of the optical path is changed. The present invention relates to an optical axis adjustment method in an optical receiving module that adjusts the optical axes of an optical fiber and a light receiving element through an optical axis adjusting means so that the light emitted from the optical fiber can enter the light receiving element.

[Conventional technology]

When optically coupling a photodetector and an optical fiber, the photodetector is placed on the same plane as electronic components such as a preamplifier IC, and the optical fiber is There is a structural type that uses a slope formed at the tip to convert the optical path by 90 degrees and couple the light. Then, as part of the front axis adjustment, adjustment (xy
Directional adjustment) can be performed relatively easily by measuring the tolerance curve between the optical output on the optical fiber side and the photoelectric output on the light receiving element side. On the other hand, adjustment by moving the optical fiber in a direction perpendicular to the light-receiving surface of the light-receiving element, in other words, adjustment of the length of the optical path connecting the light-emitting part of the optical fiber and the light-input part of the light-receiving element (Z-direction adjustment or gap adjustment)
This is done by observing the optical fiber and light-receiving surface from above using a microscope, based on the difference in the depth of focus.

[Problem to be solved by the invention]

However, the measurement of the depth of focus in the gap (two-way) adjustment and the movement adjustment based on the depth of focus require extremely high levels of skill due to the required accuracy, and therefore, it is difficult to improve and improve this adjustment work. Highly desired.

In view of these points, the present invention allows the above-mentioned gap adjustment (adjustment to optimize the optical path length) to be performed easily, conveniently, and quickly, and achieves good adjustment accuracy equivalent to or better than conventional adjustment methods. An object of the present invention is to provide a method for adjusting the optical axis of an optical receiving module that can obtain the following.

[Means to solve the problem]

In order to solve the above problems, a method for adjusting the optical axis of an optical receiving module according to the present invention is such that an optical fiber having a sloped surface for changing the direction of the optical path at its tip is substantially parallel to the light receiving surface of a light receiving element fixed in a package. The optical axis of the optical fiber and the light receiving element is adjusted through the optical axis adjusting means so that the optical path direction is changed so that the light emitted from the optical fiber can enter the light receiving element. In the optical receiver module, an ultra-compact optical system connected to a monitor camera is inserted and arranged inside the package, and is directly opposed to the length of the optical path connecting the light output part of the optical fiber and the light input part of the light receiving element. The structural feature is that this is monitored from the side so that the optical path length becomes the optimum length.

[For production]

An ultra-compact optical system connected to a monitor camera is placed directly in front of the length of the optical path connecting the light output part of the optical fiber and the light input part of the light receiving element, and is monitored from the side. Since the optical axis is adjusted based on this, the adjustment accuracy is improved and the adjustment time can be shortened.

〔Example〕

The present embodiment will be described below with reference to the drawings.

FIG. 1 is an overall schematic configuration diagram of an embodiment of the optical axis adjustment device for an optical receiving module according to the present invention, and FIG.
FIG. 3 is a cross-sectional view taken along the line in the direction of the arrow.

In short, the optical axis adjustment device of this embodiment can be summarized as package 1.
Regarding the gap (optical path length) adjustment between the light receiving element 2 fixedly installed at the internal bottom part of the optical fiber 3 and the optical fiber 3, this length is monitored from the side and is fully automatically adjusted.

An optical fiber 3 having a slope for changing the direction of the optical path at its tip end is inserted through the side wall of the package 1 and arranged parallel to the light receiving surface of the light receiving element 2 .

Further, the optical fiber 3 is connected to a known three-dimensional fine movement drive bag f (XYZ stage) 5 via an arm 4 etc., and is connected to the in-plane (XY) direction parallel to the light receiving surface of the light receiving element 2 and perpendicular thereto. (Z) direction. Note that 6 is a holder for actually fixing the optical fiber 3 to the package 1 after adjusting the optical axis.

The XYZ stage (three-dimensional fine movement drive device) 5 is a commercially available so-called fine movement table with a built-in motor and the like.

The Y and Z axes are combined so that they are perpendicular to each other, and are actually driven by a commercially available XYZ stage controller 8.

The XYZ stage controller 8 is connected to a computer 9 and is controlled by instructions from the computer 9.

The ultra-compact optical system 11, which can be inserted from above into the package 1 during optical axis adjustment, consists of a small right-angle prism 12, a microlens system 13, etc., and connects the light output part of the optical fiber 3 and the light input part of the light receiving element 2 The length of the optical path connecting the (gap)
It is placed in an empty space between the side wall of the package 1, the optical fiber 3, and the light receiving element 2 so that it can be monitored while directly facing the optical fiber (FIG. 2). At the top of the optical system 11, the optical system 1
1, a monitor camera 15 is connected which converts a subject image formed on an internal photoelectric conversion element into a time-series electric signal and outputs the signal as a video signal. Monitor camera 1
5 includes an image processing device 16 and a monitor television 1 to which a video signal outputted by the video signal is input and performs binarization image processing or the like on the video signal to measure a target physical quantity (gap).
7 is connected. The image processing device 16 is adapted to provide the image data to the computer 9 connected thereto.

The process of actually adjusting the optical axis between the optical fiber and the light receiving element using the apparatus of this embodiment having the above configuration will be described.

First, the optical system 11 is inserted into the package 1 from above and placed in a predetermined position, and then the optical fiber 3 is slowly inserted into the package 1.

Next, from the image data obtained by monitoring the optical fiber 3 and the light-receiving element 2 from the side, the computer 9 or the like determines the direction of the optical fiber 3 in its longitudinal direction (for example, the X direction) and in the direction of the light-receiving surface of the light-receiving element 2 ( X direction) to a predetermined initial position (at this time, the gap between the optical fiber 3 and the light receiving element 2 is set to about 20 microns)
.

Next, the light source 19 connected to the other external end of the optical fiber 3 is caused to emit light so that it enters the light receiving element 2, and a bias voltage is applied to the light receiving element 2 to determine the tolerance curve of the photoelectric output. Read by computer 9,
Based on this, rough adjustment of the optical fiber 3 in the XY plane direction is performed.

Then, the gap is adjusted again based on the image processing data (to about 10 microns), the tolerance curve is measured, and the optical fiber 3 is finally adjusted in the X and Y directions so as to be at the center of the curve.

Through the above steps, the optical axis position adjustment of the optical fiber 3 in the X, Y, and X directions with respect to the light receiving element 2 is completed. Regarding the gap adjustment in the X direction, the accuracy is excellent because the length is naturally monitored from the side facing directly and the optimal length is determined based on that. Further, since the work is simple and simple, the efficiency of the adjustment work is generally improved.

Needless to say, without using the computer 9,
Semi-automatic adjustment work such as moving the optical fiber 3 manually or mechanically while visually observing the monitor camera 17 can be performed according to the present invention.

〔Effect of the invention〕

As described above, according to the present invention, the gap between the optical fiber and the light-receiving element is observed in a natural manner and adjustment is performed based on the gap, which is excellent in terms of accuracy and workability. credibility will be significantly improved.

[Brief explanation of drawings]

FIG. 1 is an overall schematic configuration diagram of an embodiment of the optical axis adjustment device for an optical receiving module according to the present invention, and FIG.
FIG. 3 is a cross-sectional view taken along the line in the direction of the arrow. 1... Package, 2... Light receiving element, 3...
Optical fiber, 11... Optical system, 16... Image processing device. 5...XYZ stage, 15...monitor camera,

Claims (1)

[Claims] 1. An optical fiber (3) having a sloped surface for changing the direction of the optical path is fixed in a package (1), and a light receiving element (2) is attached.
) is inserted through the side wall of the package (1) so that it is approximately parallel to the light-receiving surface of the optical fiber (3).
) through the optical axis adjusting means so that the light emitted from the light receiving element (2) can enter the light receiving element (2).
2) In the optical receiving module that performs optical axis adjustment, an ultra-compact optical system (11) connected to a monitor camera (15)
is inserted into the package (1), and the optical fiber (
3) The length of the optical path connecting the light emitting part and the light incidence part of the light receiving element (2) is monitored from the side so as to directly face the length of the optical path, so that the length of the optical path becomes the optimum length. A method for adjusting the optical axis of an optical receiving module, characterized by: