JP2004252244A - Optical fiber collimator array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber collimator array which can be assembled with high accuracy at low cost. <P>SOLUTION: The optical fiber collimator array has an optical fiber collimator array 2A which is arranged with a plurality of optical fibers 5 in a specified direction, a microlens array 3A arranged with a plurality of microlenses 9 in a specified direction and a spacer 4A which is arranged between the array 2A and the array 3A and has a prescribed thickness. The peripheral parts of substrates 6 and 10 respectively constituting the array 2A and the array 3A are provided with guide bores 7a and 7c of a cylindrical shape and guide pins 11 having external diameter dimensions approximately equal to the bore diameter of the guide bores 7a and 7c are inserted into the guide bores 7a and 7c of the array 2A and the array 3A, and thereby the array 2A and the array 3A are aligned and fixed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical fiber collimator array, and is used, for example, in a connection between an optical function circuit such as an optical switch, an isolator, and a semiconductor laser module in an optical communication system and an optical fiber.
[0002]
[Prior art]
Due to a rapid increase in data traffic, there is a demand for an increase in the capacity of a backbone network. A large-capacity optical network using WDM (Wavelength division multiplexing) technology has already been introduced into the transmission path portion of the network. However, in the node portion, a method has been adopted in which an optical signal is once converted into an electric signal, a route is switched by a switch using a conventional electric circuit, and then converted back to an optical signal and returned to the network. I have.
[0003]
It has been pointed out that the cost and power consumption of such an apparatus for converting an electric signal into an optical signal or an optical signal into an electric signal greatly increase with an improvement in the signal band (see "AS. Morris III, "In search of transparent networks", IEEE Spectrum, pp. 47-51, Oct. 2001). Then, in order to solve this problem, the introduction of an optical switch that switches an optical signal as light is being actively promoted. In particular, a free space type optical switch that uses a light beam for connection inside a switch and for connection between switches can be configured in a large-scale optical switch in a compact manner. Expected.
[0004]
FIG. 4 is a schematic diagram showing an example of a conventional free-space optical switch (see Non-Patent Document 1).
The free space type optical switch mainly includes an optical fiber collimator array 21, a micro movable mirror array 26 having a plurality of micro movable mirrors, and a fixed mirror 27 fixed at a predetermined position and angle.
[0005]
The optical fiber collimator array 21 includes an optical fiber array 22 holding a plurality of optical fibers, a microlens array 23 having a plurality of microlenses, and a spacer disposed between the optical fiber array 22 and the microlens array 23. 24. Each of the micro movable mirrors of the micro movable mirror array 26 is an active element formed on a semiconductor substrate by using a micromachine manufacturing technique, and dynamically changes the tilt angle θ of the mirror surface shown in FIG. Is what you can do. In FIG. 4, for the sake of simplicity, components (optical fibers, microlenses, and micro movable mirrors) arranged one-dimensionally are shown, but an optical fiber array 22, a micro lens array 23, and a micro movable mirror array are shown. Reference numeral 26 denotes a plurality of optical fibers, microlenses, and micro movable mirrors, each of which is two-dimensionally arranged.
[0006]
Arrows a, b, c, and d shown in FIG. 4 indicate the traveling directions of the light beam 25. Specifically, the light beam 25 emitted from each optical fiber constituting the optical fiber collimator array 21 is converted into parallel light by the micro lens of the micro lens array 23 and reaches the micro movable mirror of the micro movable mirror array 26. (Arrow a). The light beam 25 reflected by the micro movable mirror reaches the fixed mirror 27 (arrow b), is reflected by the fixed mirror 27, reaches another micro movable mirror (arrow c), and is reflected by another micro movable mirror. Then, the traveling direction is changed to reach the microlens (arrow d), and the light is finally focused on the optical fiber by the microlens. At this time, by changing the tilt angle θ of the micro movable mirror, the traveling direction of the light beam 25 can be changed, and an optical signal can be guided to a desired optical fiber.
[0007]
The connection loss and crosstalk generated inside such a conventional optical switch are caused by the amount of misalignment between the optical components constituting the optical switch, particularly, the optical fiber array and the microlens array constituting the optical fiber collimator array. Depends on the amount of displacement. For this reason, the conventional optical switch requires a two-dimensional optical fiber array in which optical fibers are arranged with high precision and a two-dimensional microlens array in which microlenses are arranged with high precision. There is a need for a highly accurate alignment technique with a microlens array.
[0008]
FIG. 5 is a perspective view showing an example of a conventional optical fiber collimator array (see Non-Patent Document 2).
The configuration of the conventional optical fiber collimator array 31 shown in FIG. 5 will be briefly described. An optical fiber array 32 holding a plurality of optical fibers 35, a microlens array 33 having a plurality of microlenses 36, It comprises a spacer 34 disposed between the optical fiber array 32 and the microlens array 33. A method of manufacturing the conventional optical fiber collimator array 31 having such a configuration will be described with reference to FIG.
[0009]
First, the microlens array 33 is bonded and fixed to a spacer 34 having a space at the center. Next, the microlens array 33 to which the spacer 34 is attached and the optical fiber array 32 are brought close to each other, and the optical axis positions of the optical fibers 35 constituting the optical fiber array 32 and the corresponding microlenses 36 are substantially the same. To be arranged. Then, a laser light source is connected to the optical fibers 35 at the four corners of the optical fibers 35 constituting the optical fiber array 32, and the shape of the light beam emitted through the microlens array 33 and the intensity center position are determined by the laser light source wavelength. The position of the micro lens array 33 is adjusted while monitoring using a monitor camera or the like having high sensitivity. When a desired light beam propagation characteristic is obtained, the optical fiber array 32 is bonded and fixed to the spacer 34 to which the microlens array 33 is fixed at that position.
[0010]
[Non-patent document 1]
D. T. Neilson, et al. , "Fully provisioned 112x112 micro-mechanical optical crossconnect with 35.8 Tb / s demonstrated capacity", in procedures of the Federation of Fiber Optic Corporation. 202-204, 2000
[Non-patent document 2]
Yamamoto and 6 others, “3-D MEMS large-scale optical switch”, IEICE Technical Report, PS2002-55, pp. 35-40, 2002
[0011]
[Problems to be solved by the invention]
However, in the conventional optical fiber collimator array 31 shown in FIG. 5, the alignment between the optical axes of the optical fibers 35 forming the optical fiber array 32 and the microlenses 36 forming the microlens array 33 is performed. Not only high accuracy of several μm (micron) or less is required, but also the effect of shrinkage of the adhesive when performing adhesive fixing cannot be ignored. The production of parts with such high-precision alignment and precise management of the contraction state of the adhesive is not suitable for mass production, and it is not easy to reduce the production cost.
[0012]
Further, when assembling an optical switch or the like, it is necessary to change the thickness of the spacer 34 for adjusting the propagation state of the light beam as needed due to a change in the layout of the optical components. However, in the conventional optical fiber collimator array 31, since each component is bonded and fixed, this adjustment, that is, the thickness of the spacer 34 cannot be changed.
[0013]
The present invention has been made in view of the above problems, and has as its object to provide an optical fiber collimator array that can be assembled with high accuracy and at low cost.
[0014]
[Means for Solving the Problems]
An optical fiber collimator array according to the present invention that solves the above problems includes an optical fiber array in which a plurality of optical fibers are arranged in a certain direction, a microlens array in which a plurality of microlenses are arranged in a certain direction, A plurality of cylindrical guide holes are provided between the fiber array and the microlens array, the spacers having a predetermined thickness, and a plurality of cylindrical guide holes are provided around a substrate constituting each of the optical fiber array and the microlens array. The optical fiber array and the micro lens array are inserted by inserting a guide pin having an outer diameter approximately equal to the hole diameter of the guide hole into each of the guide holes of the optical fiber array and the micro lens array which are arranged opposite to each other. Are positioned and fixed.
[0015]
In addition, the optical fiber collimator array according to the present invention that solves the above-mentioned problem has a long cross-sectional shape of at least one guide hole of one of the substrates constituting the optical fiber array and the microlens array. It is characterized by having a hole shape.
[0016]
In addition, the optical fiber collimator array according to the present invention that solves the above-mentioned problems, both or one of the substrates constituting the optical fiber array and the microlens array is made of a material having a high elastic modulus such as a polymer resin. It is characterized by the following.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of an optical fiber collimator array according to the present invention will be described with reference to the drawings.
[0018]
(Example 1)
FIG. 1 shows an example of an embodiment of an optical fiber collimator array according to the present invention, in which each component constituting the optical fiber collimator array is shown in a perspective view.
The optical fiber collimator array 1A according to the present invention mainly includes an optical fiber array 2A, a microlens array 3A, and a spacer 4A disposed between the optical fiber array 2A and the microlens array 3A and having a predetermined thickness. It consists of.
[0019]
The optical fiber array 2A has a plurality of optical fibers 5 and a fiber alignment substrate 6 having a plurality of holes formed at regular intervals in the center, and each optical fiber 5 is arranged in a fixed direction. Then, the fiber alignment substrate 6 is bonded and fixed to a plurality of holes. Furthermore, guide holes 7a having a cylindrical shape (circular cross section) are provided at two locations around the fiber alignment substrate 6. The microlens array 3A is composed of a microlens array substrate 10 having a plurality of microlenses 9 arranged at regular intervals and in a constant direction at a central portion. Guide holes 7b each having a circular cross section are provided. The spacer 4A has a hollow portion 8 in the center thereof through which an optical signal passes, and the same cylindrical shape (circular shape) as described above is also provided at two places on the substrate of the spacer 4A which is a peripheral portion of the hollow portion 8. (Cross section) guide hole 7c is provided. In the present embodiment, the optical fibers 5 and the microlenses 9 are arranged two-dimensionally and at equal intervals. However, the present invention is not necessarily limited to these forms, and the present invention can be applied.
[0020]
The guide holes 7a, 7b, and 7c (guide holes) are located at the same position when the fiber alignment substrate 6 and the microlens array substrate 10 are overlapped with the spacer 4A interposed therebetween. Is formed. By inserting guide pins 11 having outer dimensions substantially equal to the diameters of the guide holes 7a, 7b, 7c into these guide holes 7a, 7b, 7c, the optical fiber array 2A and the microlens array 3A can be easily connected. It is possible to perform positioning and close contact fixing. The number of guide holes 7a, 7b, 7c in each substrate is not necessarily limited to two, but may be plural. Further, the guide hole 7c of the spacer 4A does not necessarily have to be the same size as the guide holes 7a and 7b, and may be any size as long as the guide pin 11 can be inserted. Further, if the hollow portion 8 can be reliably secured and the optical fiber array 2A and the microlens array 3A can be accurately positioned and fixed, it is not always necessary to provide them.
[0021]
Next, a method of assembling the optical fiber collimator array according to the present invention will be described with reference to FIG.
First, as shown in FIG. 2A, the microlens array 3A and the spacer 4A are aligned and overlapped, and the guide pins 11 are inserted from the guide holes 7b of the microlens array 3A into the guide holes 7c of the spacer 4A. Next, as shown in FIG. 2B, the position of the optical fiber array 2A is overlapped with the position of the microlens array 3A and the spacer 4A, and the guide pin 11 is inserted into the guide hole 7a of the optical fiber array 2A. Finally, as shown in FIG. 2C, the components are closely fixed.
[0022]
As described above, in the method for assembling the optical fiber collimator array according to the present invention, since the alignment between the optical fiber array 2A and the microlens array 3A is performed using the guide pins 11, it is not necessary to use an adhesive, and Since no fine adjustment by a monitor camera or the like is required, the assembly of the optical fiber collimator array 1A can be completed by an extremely simple method. Further, since the alignment position between the optical fiber array 2A and the microlens array 3A is determined by the guide pins 11, it is not necessary to consider the influence of the optical axis shift due to the contraction of the adhesive unlike the related art.
[0023]
Generally, the distance in the optical axis direction between the output end face of the optical fiber and the main surface of the microlens array has a different optimum value depending on the optical system constituting the optical switch or the like. In the conventional optical fiber collimator array, since the components were bonded and fixed, it was not possible to change to spacers having different thicknesses. However, in the optical fiber collimator array according to the present invention, the guide pins 11 were used. Since the components are tightly fixed to each other, the spacer 4A can be removed, and a spacer having a different thickness can be changed as needed. That is, the distance in the optical axis direction between the optical fiber emitting end face and the main surface of the microlens array can be appropriately changed according to the optical system to be used.
[0024]
The amount of displacement between the optical fiber 5 and the optical axis of the microlens 9 is determined by the position of the guide hole 7a formed in the optical fiber array 2A and the position of the guide hole 7b formed in the optical fiber optical axis and the microlens array 3A. It depends on the relative displacement between the position and the optical axis of the microlens, and the difference (clearance) between the diameter of the guide holes 7a and 7b and the outer diameter of the guide pin 11.
[0025]
(Example 2)
FIG. 3 is a perspective view showing another example of the embodiment of the optical fiber collimator array according to the present invention, in which the vicinity of the guide hole 12 is enlarged in the drawing. The basic configuration of the optical fiber collimator array of the present embodiment is almost the same as the optical fiber collimator array of the first embodiment shown in FIG. The typical part is explained.
[0026]
As shown in FIG. 3, the optical fiber collimator array 1B of this embodiment mainly includes an optical fiber array 2A, a microlens array 3B, and a spacer arranged between the optical fiber array 2A and the microlens array 3B. 4A. The difference from the optical fiber collimator array 1A of the first embodiment shown in FIG. 1 is that in the microlens array 3A of the optical fiber collimator array 1A shown in FIG. 1, the guide hole 7b is a through hole having a simple circular cross section. On the other hand, in the microlens array 3B of the optical fiber collimator array 1B of the present embodiment, one of the guide holes 12 is a through hole having an elongated cross section. The other guide hole 7b of the microlens array 3B of the present embodiment is a through hole having a circular cross section equivalent to the guide hole 7b of the microlens array 3A of the first embodiment.
[0027]
The guide hole 12 is, as shown in an enlarged view in FIG. 3, a through hole having an oblong oval cross section, so that the guide pin 11 can be disposed at an appropriate position inside the guide hole 12. Has become. That is, in order to insert the guide pin 11 into the guide hole 12 more easily, the hole diameter of the guide hole 12 is made slightly larger than the outer diameter of the guide pin 11, and a clearance is provided.
[0028]
In order to easily insert the guide pin into the guide hole, it is usually necessary to make the hole diameter of the guide hole slightly larger than the outer diameter of the guide pin to provide a clearance. If the clearance is small, it becomes difficult to insert the guide pin. On the other hand, if the clearance is large, the deviation of the optical axis between the optical fiber and the microlens in the optical fiber collimator array is increased. Further, in consideration of the position of the guide hole formed on the optical fiber array and the microlens array, and the influence of the relative displacement between the optical fiber optical axis and the microlens optical axis, it is further necessary to reduce the clearance. difficult.
[0029]
In order to solve such a problem, in this embodiment, the cross-sectional shape of at least one of the two guide holes 7b and 12 formed in the microlens array 3B is set to be a long hole shape, and the guide hole 12 is formed. The required clearance is increased, and the influence of the increase in the amount of displacement of the optical axis between the optical fiber and the microlens due to the size of the clearance is suppressed.
[0030]
That is, at least one of the guide holes 12 of one of the substrates (the microlens array substrate 10 of the microlens array 3B in this embodiment) of the substrates constituting the optical fiber array 2A and the microlens array 3B, respectively. The cross-sectional shape is a long hole, the clearance is increased, and the adjusting side for alignment is used, and the cross-sectional shape of the guide hole 7a on the other side (in this embodiment, the fiber alignment substrate 11 of the optical fiber array 2A). Is circular and used as a reference side for alignment. With such a configuration, despite the provision of a clearance in the guide hole 12 to facilitate insertion of the guide pin 11, the size of the clearance has as little influence as possible on the alignment accuracy between the optical fiber and the microlens. It has no effect.
[0031]
(Example 3)
Still another example of the embodiment of the optical fiber collimator array according to the present invention will be described.
The optical fiber collimator array of the present embodiment may have substantially the same configuration as the first and second embodiments shown in FIGS. However, the present embodiment is characterized in that a material having a relatively high elastic modulus such as a polymer resin is used as a material of the fiber alignment substrate and the microlens array substrate constituting the optical fiber array. Generally, the material of the fiber alignment substrate and the microlens array substrate constituting the optical fiber array is made of an inelastic material, for example, metal or glass, and in this case, a guide pin is inserted into the guide hole. Requires a relatively large clearance, which may increase the amount of optical axis deviation between the optical fiber and the microlens with the size of the clearance. In order to avoid this problem, in this embodiment, both or one of the fiber alignment substrate and the microphone lens array substrate is manufactured using a polymer resin material having a relatively high elastic modulus.
[0032]
By adopting such a configuration, it is not necessary to increase the clearance of the guide hole, so that the accuracy of the optical axis alignment between the optical fiber and the microlens is maintained, and the insertion of the guide pin into the guide hole or from the guide hole. Extraction becomes easy.
[0033]
【The invention's effect】
According to the first aspect of the present invention, in the optical fiber collimator array, a plurality of cylindrical guide holes are provided around a substrate constituting each of the optical fiber array and the microlens array, and the hole diameter of the guide holes is provided. By inserting guide pins having an outer diameter approximately equal to that of the optical fiber array and the microlens array arranged opposite to each other, the optical fiber array and the microlens array are aligned and tightly fixed. As a result, the influence of shrinkage of the adhesive or the like was eliminated to improve the alignment accuracy between the optical axes of each optical fiber and each microlens, and to simplify the assembly and reduce the time required for assembly. It can be manufactured at low cost. In addition, since each component is tightly fixed using a guide pin without using an adhesive or the like, the spacer can be removed, and the thickness of the spacer can be appropriately changed according to the optical component, and the light beam can be removed. Can be adjusted.
[0034]
According to the second aspect of the present invention, at least one of the substrates constituting the optical fiber array and the microlens array has a slot-shaped cross-sectional shape of at least one guide hole. When assembling the fiber collimator array, even if the mechanical clearance required for inserting the guide pins is expanded or the accuracy of the position of the guide hole is reduced, each optical fiber and each micro lens In this case, the influence of the deterioration in the accuracy of the alignment between the optical axes can be reduced.
[0035]
According to the invention according to claim 3, both or one of the substrates constituting each of the optical fiber array and the microlens array is made of a material having a high elastic modulus such as a polymer resin. The guide pins can be easily inserted and removed without lowering the accuracy of the alignment between the optical axes of the microlenses.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of an embodiment of an optical fiber collimator array according to the present invention.
FIG. 2 is a diagram illustrating a method of assembling the optical fiber collimator array of FIG. 1;
FIG. 3 is a perspective view showing another example of the embodiment of the optical fiber collimator array according to the present invention.
FIG. 4 is a schematic diagram showing an example of a conventional free space optical switch.
FIG. 5 is a perspective view showing an example of a conventional optical fiber collimator array.
[Explanation of symbols]
1A, 1B Optical fiber collimator array 2A Optical fiber array 3A, 3B Micro lens array 4A Spacer 5 Optical fiber 6 Fiber alignment substrate 7a, 7b, 7c Guide hole 8 Hollow portion 9 Micro lens 10 Micro lens array substrate 11 Guide pin 12 Guide hole

Claims (3)

An optical fiber array in which a plurality of optical fibers are arranged in a certain direction, a microlens array in which a plurality of microlenses are arranged in a certain direction, arranged between the optical fiber array and the microlens array, In an optical fiber collimator array having a spacer having a predetermined thickness,
A plurality of cylindrical guide holes are provided in the peripheral portion of the substrate constituting each of the optical fiber array and the microlens array,
By inserting a guide pin having an outer diameter dimension substantially equal to the hole diameter of the guide hole into each of the guide holes of the optical fiber array and the microlens array arranged opposite to each other, the optical fiber array and the An optical fiber collimator array, wherein the optical fiber collimator array is aligned and fixed with a microlens array. The optical fiber collimator array according to claim 1,
An optical fiber collimator array, wherein at least one of the guide holes of one of the substrates constituting the optical fiber array and the microlens array has a long hole shape in cross section. The optical fiber collimator array according to claim 1 or 2,
An optical fiber collimator array, wherein at least one of the substrates constituting the optical fiber array and the microlens array is made of a material having a high elastic modulus.

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