JP3343756B2 - Manufacturing method of collimator for optical circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a collimator for an optical circuit, and more particularly to a method for manufacturing a collimator for an optical circuit that collects light emitted from an optical fiber, converts the light into a parallel beam, and outputs the parallel beam. .

[0002]

2. Description of the Related Art FIG. 3 is a schematic view showing a method for manufacturing a conventional optical circuit collimator (in this case, an optical fiber collimator). As shown in FIG. 3, a conventional optical fiber collimator (referred to as a second collimator) 20 is an optical fiber 7a and an optical fiber collimator 1 which is manufactured by optically coupling with the optical fiber 7a. Optical adjustment for coupling and coupling the parallel beam 2 output from the first optical fiber collimator (referred to as a first collimator) 1 to the output side optical fiber 7 attached to the second collimator 20 with minimum loss. It was manufactured by.

That is, in FIG. 3, an optical lens 3 receiving a parallel beam 2 is fixed to a lens holder 4,
This lens holder 4 is fixed to the sleeve 5. In this case, a ferrule 6 to which an optical fiber 7 is fixed is inserted into the sleeve 5. The above-mentioned optical adjustment is performed while holding the sleeve 5 and adjusting the axis in the xy direction and the angle adjustment in the xz plane and the yz plane while the ferrule 6 to which the optical fiber 7 is fixed is attached to the sleeve 5. 5
And the light condensed by the optical lens 3 is coupled to the fiber 7 with minimum loss, and the ferrule 6 is fixed to the sleeve 5 in this state. The above is the outline of the method of manufacturing the conventional optical fiber collimator.

[0004]

However, in the above-described conventional method for manufacturing an optical fiber collimator, the second method for receiving the light emitted from the first collimator 1 in order to manufacture a pair of optical fiber collimators. Collimator 2
The second collimator 20 is axially adjusted in the xy plane, and two angles are adjusted in the xz plane and the yz plane while moving the optical fiber 7 constituting 0 in the sleeve 5 in the z-axis direction. Is required. Such a complicated adjustment requires a great deal of man-hours and causes an increase in manufacturing cost.

[0005]

[0006]

A method for manufacturing a collimator for an optical circuit according to the present invention comprises a first optical lens and a first optical lens .
In a method of manufacturing a collimator for an optical circuit in which a second collimator is optically coupled to a first collimator constituted by an optical element and a predetermined collimator facing distance by an optical adjustment means, the collimator is fixed in a sleeve of the second collimator. The second
The distance between the optical lens and the second optical element inserted into the ferrule fixed in the sleeve, and the relationship between the opposing distances of the collimators, are prepared in advance with the condition characteristics that minimize the coupling loss opposing the collimators. place, combined optical axis of the second collimator is disposed on the optical axis of the first collimator, the
The reflected return light of the optical lens end face of the second optical lens and the optical element end face of the second optical element is detected, and the reflected return light is detected.
The distance between the second optical lens and the second optical element was measured from the output, by applying the conditions characteristic during the measurement, and a second optical lens corresponding to the desired collimator facing distance a
The position of the ferrule is adjusted and fixed so that the distance between the two optical elements is obtained.

In the method for manufacturing an optical fiber collimator just described, the optical element of the second collimator is constituted by one of a light emitting element and a light receiving element comprising an optical fiber or an optical semiconductor element or an optical waveguide. Is also good.

[0008]

According to the present invention, the second optical lens of the second collimator to be coupled to the first collimator is provided.
The distance between the second optical element, and leave Prepare a condition characteristic relationship collimator facing distance to minimize the collimator opposed coupling loss previously, the second optical fixed to the second collimator in the sleeve The second light inserted into the optical lens end face of the lens and the ferrule fixed in the sleeve
Detecting the reflected return light of the optical device end face academic elements, the reflection
From the detection of the return light, the second optical lens and the second optical element
And measuring the distance between the second light beams corresponding to the desired collimator facing distance using the above-mentioned condition characteristics during this measurement.
Since the position of the ferrule is adjusted and fixed so that the distance between the optical lens and the second optical element is obtained, the optical characteristics of the collimator for an optical circuit are almost the same in a combination of the same type of lens and optical element. The manufacturing method becomes uniform. Therefore, troublesome optical adjustment is not required.

[0009]

FIG. 1 is a schematic explanatory view of a second collimator showing one embodiment of a method of manufacturing a collimator for an optical circuit according to the present invention. First, it is known that the opposing loss characteristic of the collimator is determined by the distance between the lens and the fiber when the central axis of the lens constituting the collimator and the central axis of the optical fiber are on the same axis. Also, by using this principle, a condition for minimizing the opposing loss is found, and by setting the condition specifically,
Adjustments related to the manufacturing method are performed.

Therefore, in the embodiment shown in FIG. 1, the lens 8 constituting the second collimator, the ferrule 10 to which the fiber 9 is fixed, and the center axis of the lens 8 and the center axis of the optical fiber 9 are aligned. And a sleeve 11. In this collimator configuration, first, the lens 8 is fixed to the sleeve 11, and the distance between the end face 8 a of the lens 8 and the end face 9 a of the optical fiber 9 is set to be equal to the incident light 12 incident from the end face 9 b of the optical fiber 9. End face 9a of fiber 9
The ferrule 10 and the sleeve 11 are fixed at a predetermined distance at which the minimum opposing loss can be obtained, while detecting the reflected return light generated from the lens end face 8a and measuring the optical distance between the reflection points.

Since the present predetermined distance differs depending on the type of the lens constituting the collimator, the type of the optical fiber, and the facing distance of the collimator, the characteristic depends on the combination of these conditions. Ask for it. FIG. 2 shows an example of this characteristic. The horizontal axis of the characteristic diagram of FIG. 2 is the distance between the collimators, and the vertical axis is the set distance d (the above-described predetermined distance) between the lens and the optical fiber.

The characteristic diagram of FIG.
This is an example of characteristics in the case of a 5 mm spherical lens and a 1.3 zero dispersion single mode fiber (core diameter 10 μm, relative refractive index difference 0.3%). Here, the collimator facing distance is 5 to 5
When the distance is set to 5 mm, the distance d between the lens and the fiber at which the minimum opposing loss is obtained is shown. In addition, the collimator facing distance refers to the distance between the facing end faces of the collimator 20 and the collimator 1 that are coupled to each other, for example, in FIG.

As is apparent from FIG. 2, the relationship between the facing distance of these collimators and the distance between the lens and the fiber can be approximated by a straight line. Therefore, in the optical adjustment for manufacturing the collimator, for example, the characteristic diagram of FIG. 2 is used, and when the opposing distance of the desired collimator is, for example, 40 mm, the distance between the lens and the fiber may be set to 665 μm. For the optical measurement described above, a commercially available measuring instrument (for example, H
P-8504A: Precision Reflectometer) can be used.

In this embodiment, the adjustment for performing the above-mentioned measurement allows the desired collimator facing distance to be adjusted.
Since the distance d between the lens 8 and the optical fiber 9 can be adjusted with an accuracy within ± 5 μm, a sufficiently low-loss optical circuit collimator can be manufactured.

In the above embodiment, the BK-7 diameter is 2.5 m.
An example using a spherical lens of m and a 1.3 zero-dispersion single mode fiber has been described, but a characteristic diagram or data showing the relationship as shown in FIG. 2 in some combinations of lenses and fibers constituting a collimator. Can be determined by measuring the distance between the lens end face and the position where the reflected return light is generated on the fiber end face, and the same optical adjustment can be performed using this.

As described above, according to the above-described embodiment, the ferrule 10 in which the optical fiber 9 is fixed to the center axis thereof is moved in the sleeve 11 so that the two reflection returns of the lens end face 8a and the optical fiber end face 9a are performed. Since the position between the lens 8 and the optical fiber 9 is adjusted to a predetermined distance while measuring the position from the light, the ferrule 10 is fixed to manufacture an optical fiber collimator.
With this combination, an optical fiber collimator having substantially uniform optical characteristics can be manufactured in a large amount in a short time. And since troublesome optical adjustment is not required,
An inexpensive optical fiber collimator can be provided. Further, according to the manufacturing method of the optical fiber collimator as in this embodiment, even if the optical fiber collimator is arbitrarily selected, the distance between the optical fiber 9 and the lens 8 is adjusted and fixed to a constant value with high accuracy. Therefore, a collimator facing characteristic with low coupling loss can be obtained, so that even if it becomes unusable due to an accident such as a fiber break, there is an advantage that another collimator can be supplied immediately to cope with it.

In addition to the fiber collimator composed of the lens and the optical fiber as in the above-described embodiment,
A lens and, for example, a semiconductor laser element, a collimator composed of a light emitting element such as an LED, and a lens and, for example, a PI
The present invention can be applied to a collimator constituted by a light receiving element such as an N-PD or an APD, or a collimator for an optical circuit constituted by a lens and an optical waveguide.

[0018]

As described above, according to the present invention, the first
The second collimator to try to bind to the collimator
The relationship between the distance between the second optical lens and the second optical element , and the relationship between the opposing distances of the collimators, is prepared in advance to have a condition characteristic that minimizes the coupling loss opposing the collimators, and is fixed in the sleeve of the second collimator. The reflected return light of the optical lens end face of the second optical lens and the optical element end face of the second optical element inserted in the ferrule fixed in the sleeve is detected . With optical lens
The distance between the second optical element was measured, using the conditions described above characteristics during the measurement, between the second optical lens and the second optical element corresponding to the desired collimator facing distance Since the position of the ferrule is adjusted and fixed so that the distance can be obtained, a large number of optical circuit collimators with almost uniform optical characteristics can be used in a combination of the same type of lens and optical element. The effect of being able to manufacture with is obtained. And since troublesome optical adjustment is not required,
An inexpensive optical circuit collimator can be provided. Further, according to the method of manufacturing a collimator for an optical circuit according to the present invention, even if the optical fiber collimator is arbitrarily selected , the distance between the optical element and the lens is adjusted and fixed to a constant value with high accuracy. Therefore, a collimator facing characteristic with low coupling loss is obtained, so that even if the fiber cannot be used due to an accident such as fiber breakage, another collimator can be immediately supplied to cope with the advantage.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a second collimator showing one embodiment of a method for manufacturing an optical circuit collimator according to the present invention.

FIG. 2 is a characteristic diagram showing a condition relationship in which opposing coupling loss between a collimator opposing distance and a lens-fiber distance is the minimum.

FIG. 3 is a schematic view illustrating a method of manufacturing a conventional optical circuit collimator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical fiber collimator (1st optical fiber collimator) 2 Parallel beam 3 Optical lens 4 Lens holder 5,11 Sleeve 6,10 Ferrule 7,7a, 9 Optical fiber 8 Lens 8a, 9a, 9b End face 12 Incident light 13 Reflection return Light 20 Optical fiber collimator (second collimator)

Claims (4)

(57) [Claims] 1. An optical circuit collimator for optically coupling a second collimator to a first collimator comprising a first optical lens and a first optical element via a predetermined collimator facing distance by an optical adjustment means. of the manufacturing method, the second secured within the second collimator sleeves
The distance between the optical lens and the second optical element inserted in the ferrule fixed in the sleeve, and the relationship between the opposing distances of the collimator, preliminarily prepare a condition characteristic that minimizes the coupling loss opposing the collimator. place the first collimators combined optical axis of the second collimator on an optical axis arranged, said second optical lens end face of the optical lens and the second light
Detecting the reflected return light of the optical device end face of the academic element, the said second optical lens from the detection of the reflected return light
The distance between the second optical element and the second optical lens corresponding to the desired collimator facing distance is measured by applying the condition characteristic during the measurement.
A method for manufacturing a collimator for an optical circuit, comprising adjusting and fixing a position of the ferrule so that a distance between the ferrule and a second optical element is obtained. 2. The method for manufacturing a collimator for an optical circuit according to claim 1, wherein said optical element is an optical fiber. 3. The method according to claim 1, wherein the optical element is one of a light emitting element and a light receiving element. 4. The method according to claim 1, wherein the optical element is an optical waveguide.