JP2005173213A - Optical collimator and optical component using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical collimator which can be easily applied to a tape fiber and an optical component using the optical collimator. <P>SOLUTION: An optical collimator 10 provided with a tape fiber 12 constituted of collectively covering a plurality of optical fibers 13 with a coat and a plurality of collimator lenses 11 connected to the end faces 13a of respective optical fibers 13 of the tape fiber 12 is used. In addition, an optical collimator 20 provided with 1st and 2nd tape fibers 22, 24 respectively constituted of collectively covering a plurality of optical fibers 23, 25 with coats and a plurality of collimator lenses 21 connected to the end faces 23a, 25a of respective optical fibers 23, 25 of the tape fibers 22, 24 and constituted so that any one of the optical fibers 23 of the 1st tape fiber 22 and any one of the optical fibers 25 of the 2nd tape fiber 24 are connected to the end faces 21b on the same side of the collimator lenses 21 is also used. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical functional component used in the field of optical communication, and more particularly to an optical collimator that optically couples optical fibers with a collimator lens and an optical component using the same.

2. Description of the Related Art In recent years, wavelength division multiplexing (hereinafter, abbreviated as “WDM”) technology for multiplexing and transmitting a plurality of optical signals having different wavelengths in both directions or in one direction is becoming widespread. In the WDM technology, a plurality of optical signals having different wavelengths are combined and combined into a wavelength-multiplexed optical signal, or the wavelength-multiplexed optical signal is split into a plurality of optical signals having different wavelengths. An optical multiplexer / demultiplexer is used.
As the optical multiplexer / demultiplexer, as shown in FIG. 4, two optical fiber collimators 110 and 120 (hereinafter sometimes simply referred to as “optical collimators”) are arranged so as to face each other, and a dielectric is provided between them. An optical multiplexer / demultiplexer 101 having a configuration in which an optical functional element 102 such as a multilayer filter is disposed is known (for example, see Patent Document 1).

An optical multiplexer / demultiplexer 101 shown in FIG. 4 includes an optical functional element 102 having an optical multiplexing / demultiplexing function, and first and second collimating lenses 111 and 121 disposed on both sides of the optical functional element 102. The optical functional element 102 and the first and second collimating lenses 111 and 121 are accommodated in a cylindrical holder 103.
A ferrule 112 is bonded to the end surface of the first collimating lens 111 opposite to the optical functional element 102. An optical fiber 113 serving as a C port is inserted into the ferrule 112 and connected to the first collimating lens 111 with an adhesive or the like. The first optical collimator 110 includes the first collimating lens 111, a ferrule 112, and a C-port optical fiber 113.
A ferrule 122 is joined to the end surface of the second collimating lens 121 opposite to the optical functional element 102. An optical fiber 123 serving as a B port and an optical fiber 125 serving as an A port are separately inserted into the ferrule 122 and connected to the second collimating lens 121 by an adhesive or the like. The second optical collimator 120 includes the second collimating lens 121, a ferrule 122, a B port optical fiber 123, and an A port optical fiber 125.
According to such an optical multiplexer / demultiplexer 101, when light multiplexed in wavelength (for example, λ ₁ + λ ₂ ) is incident from the A port 125, this light is transmitted through the second collimating lens 121 to the optical functional element. 102 is irradiated and demultiplexed by the optical functional element 102 according to the wavelength. The light λ ₁ reflected by the optical functional element 102 is emitted to the B port 123, and the light λ ₂ transmitted through the optical functional element 102 is emitted to the C port 113 through the first collimator lens 111.
Conversely, when light having a wavelength λ ₁ is incident on the B port 123 and light having a wavelength λ ₂ is incident on the C port 113, the light λ ₁ and λ ₂ are combined by the optical functional element 102, and A The light is emitted from the port 125 as wavelength-multiplexed light (λ ₁ + λ ₂ ).

At present, the application range of WDM technology is expanding not only to backbone networks but also to access networks. For optical components such as optical multiplexer / demultiplexers, miniaturization, high density, and low price (low cost) ) Demands are increasing more than ever before. At the same time, in an optical communication system using a tape fiber, an optical multiplexing / demultiplexing device having a number of optical multiplexers / demultiplexers corresponding to the number of optical fibers of the tape fiber (for example, 2, 4, 8, etc.) is mounted. A module is sought.
An example of a conventional optical multiplexing / demultiplexing module is shown in FIG. In the optical multiplexer / demultiplexer module 201 shown in FIG. 5, the same number of optical multiplexers / demultiplexers 202 as the number of optical fibers of the tape fiber are arranged in the box 203, and the optical multiplexer / demultiplexers 202 are drawn from both sides. The optical fibers 213, 223, and 225 are taped to correspond to the A port 225, B port 223, and C port 213 for the optical multiplexer / demultiplexer 202, respectively, and become tape fibers 212, 222, and 224.
US Pat. No. 4,213,677

However, in the optical multiplexing / demultiplexing module as shown in FIG. 5, the assembly work such as the handling of the optical fiber and the tape formation of the optical fiber is troublesome, and the optical fiber may be damaged during these operations. .
Other methods for realizing the optical multiplexing / demultiplexing module include a configuration using an optical fiber coupler in place of the optical multiplexer / demultiplexer in the optical multiplexing / demultiplexing module shown in FIG. 5, or a planar light waveguide (PLC). Some circuits have realized the function of multiplexing and demultiplexing. However, these methods may not satisfy the requirements regarding optical characteristics such as transmission loss and isolation. Further, in the case of an optical multiplexing / demultiplexing module configured using an optical fiber coupler, as in the optical multiplexing / demultiplexing module shown in FIG. is there.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical collimator that can be easily applied to a tape fiber and an optical component using the same.

In order to solve the above-mentioned problems, the present invention comprises a tape fiber formed by collectively covering a plurality of optical fibers, and a plurality of collimating lenses connected to the end faces of the respective optical fibers of the tape fiber. An optical collimator is provided.
Further, the present invention comprises first and second tape fibers formed by collectively covering a plurality of optical fibers, and a plurality of collimating lenses connected to end faces of the respective optical fibers of the tape fibers, The collimating lens is provided with an optical collimator in which one of the optical fibers of the first tape fiber and one of the optical fibers of the second tape fiber are connected to the end face on the same side. To do.
In the optical collimator, the collimating lens may be mainly composed of quartz glass, and the end face of the optical fiber and the collimating lens may be directly fused.
Furthermore, the present invention provides an optical component comprising the above optical collimator, another optical collimator disposed to face the optical collimator, and an optical functional element inserted between the optical collimators. To do.

In the optical collimator of the present invention, since the optical fiber taped in advance is connected to the collimating lens, for example, when introduced (adopted) in an optical communication system using a tape fiber, the optical fiber of the optical communication system and the present invention are used. The optical fiber collimator can be used simply by fusion splicing, so that it does not take time to tape the optical fiber and is excellent in workability. In addition, by using the optical collimator of the present invention, it is possible to realize miniaturization and high density of optical components.
According to the optical collimator constructed by directly fusing the collimating lens mainly composed of quartz glass with the end face of the optical fiber of the tape fiber, a smaller and more reliable optical collimator can be realized.
According to the optical component of the present invention, the optical component can be reduced in size and density. In addition, a smaller optical functional element such as a dielectric multilayer filter can be used, so that the manufacturing cost can be reduced and the cost can be reduced.

The present invention will be described below with reference to the drawings based on the best mode.
FIG. 1 is a schematic configuration diagram illustrating an example of an optical collimator according to the present invention. FIG. 2 is a schematic configuration diagram showing another example of the optical collimator of the present invention. FIG. 3A is a schematic configuration diagram showing an example of the optical component of the present invention. FIG. 3B is a front view of the optical component shown in FIG.
An optical component 1 shown in FIGS. 3A and 3B includes an optical functional element 2 such as a dielectric multilayer filter, and first and second optical collimators disposed on both sides of the optical functional element 2. 10 and 20.

As shown in FIG. 1, the first optical collimator 10 includes a tape fiber 12 in which a plurality of optical fibers 13, 13,... Are collectively covered, and each optical fiber 13, 13,. And a plurality of collimating lenses 11 connected to each other.
The number of optical fibers of the tape fiber 12 is not particularly limited, for example, 2 cores, 4 cores, 8 cores, etc., but here, 4 optical fibers (4 optical fibers 13) are used.
The optical fibers 13, 13,... Are bare optical fibers exposed by removing the resin coating 12 a at the tip of the tape fiber 12. The resin coating 12a of the tape fiber 12 is made of an ultraviolet curable resin or the like. Specifically, a plurality of primary coatings provided on the outer circumference of each bare optical fiber 13 and a plurality of optical fibers (optical fiber cores) with the primary coating, And a secondary coating that collectively coats. The end face 13a of each optical fiber 13, 13, ... is connected to one end face 11b of the different collimating lens 11, respectively. The type of the optical fiber 13 is not particularly limited, such as a single mode optical fiber or a polarization maintaining optical fiber.
In the first optical collimator 10, the end surface 11a opposite to the end surface 11b of the collimating lens 11 to which the optical fiber 13 is connected is a joint end surface (open surface).

As shown in FIG. 2, the second optical collimator 20 includes a first tape fiber 22 formed by covering a plurality of optical fibers 23, 23,... And a plurality of optical fibers 25, 25,. A second tape fiber 24 that is collectively covered and a plurality of collimating lenses 21 to which the optical fibers 23 and 25 of the first and second tape fibers 22 and 24 are connected are provided. Each collimating lens 21 is connected to one end face 21b of the first tape fiber 22 and one of the second tape fibers 24 on the same end face 21b.
The number of optical fiber cores of the tape fibers 22 and 24 is not particularly limited, for example, 2 cores, 4 cores, 8 cores, and the like. 25 is 4 each). The types of the optical fibers 23 and 25 are not particularly limited, such as a single mode optical fiber and a polarization maintaining optical fiber.
The optical fibers 23, 23,..., 25, 25,... Are bare optical fibers exposed by removing the resin coatings 22 a, 24 a at the tips of the tape fibers 22, 24.

The end face 23a of each optical fiber 23, 23,... Of the first tape fiber 22 is connected to one end face 21b of a different collimating lens 21, respectively. Further, the end surfaces 25a of the optical fibers 25, 25,... Of the second tape fiber 24 are connected to one end surface 21b of a different collimating lens 21, respectively. That is, the number of collimating lenses 21 (four in this case) is equal to the number of optical fiber cores of the tape fibers 22 and 24.
In this optical collimator 20, an end face 21a opposite to the end face 21b on the side where the optical fibers 23 and 25 of the collimator lens 21 are connected is a joining end face.

  The collimating lenses 11 and 21 used in the above-described optical collimators 10 and 20 have a cylindrical shape, and the refractive index increases as the distance from the optical axis (center axis) increases and decreases as the distance from the optical axis approaches the outer periphery. For example, GRIN lenses (also referred to as rod lenses, gradient index lenses, etc.) that gradually change and are distributed are exemplified. Light rays propagating through this type of GRIN lens travel along a sinusoidal optical path. The period of the sinusoidal optical path is called one pitch. The length of the collimating lens 11 is preferably a length represented by (2n + 1) / 4 pitch, such as about 0.25 pitch or about 0.75 pitch (where n is an arbitrary integer).

The outer diameter (lens diameter) of the collimating lenses 11 and 21 is not particularly limited as long as the collimating lens and the optical fiber can be optically connected, but the outer diameter (cladding diameter) of a general bare optical fiber is about Since the core diameter is 125 μm and the core diameter is about 10 μm, in order to connect the cores of two optical fibers to the end face of one collimating lens, the minimum is about 135 μm (the outer diameter and the core diameter of the optical fiber). Lens diameter) is required. Preferably, the lens diameter is about twice the outer diameter of the optical fiber.
In addition, as shown in FIGS. 1 and 2, each optical collimator has a lens diameter approximately equal to the optical fiber pitch d (interval between the central axes of adjacent optical fibers) in the tape fibers 12, 22, and 24. 10 and 20, it is preferable because when the collimating lenses 11 and 21 are aligned, the bending of the optical fibers 13, 23 and 25 can be suppressed to be small, and the insertion loss can be reduced.
From the above viewpoint, when the outer diameter of the bare optical fiber is about 125 μm, the lens diameter is preferably about 250 μm. Further, when the outer diameter of the bare optical fiber is about 80 μm, the lens diameter is preferably about 160 μm.

The connection method between the optical fibers 13, 23, 25 and the collimating lenses 11, 21 is not particularly limited. For example, a method of directly connecting by fusion, a method of bonding using an ultraviolet curable adhesive, A method of supporting an optical fiber using a ferrule, a glass capillary, a V-groove substrate, or the like can be employed.
Preferably, when each optical fiber 13, 23, 25 is a silica-based optical fiber and each collimating lens 11, 21 is mainly composed of quartz glass, end faces 13a, 23a, 25a of each optical fiber 13, 23, 25 are preferred. It is preferable that the end faces 11b and 21b of the collimating lenses 11 and 21 are directly fusion-connected. When a silica-based optical fiber and a collimating lens mainly composed of silica glass are fused and connected, there is no difference in the linear expansion coefficient between the two, so the fusion strength decreases due to the strain generated during cooling. There will be no problem of ending up. Moreover, since no adhesive is used, resistance to high-intensity light can be obtained.

  The length of exposure of the bare optical fibers 13, 23, 25 from the tape fibers 12, 22, 24 is not particularly limited, but the bending radius of the optical fibers 13, 23, 25 depends on the optical characteristics of the optical fiber (bending loss, etc.). It is preferable that the permissible bending radius is such that can be maintained. From the viewpoint of miniaturization of the optical collimator and prevention of damage to the optical fiber, it is preferable that the exposed length of the bare optical fiber is as short as possible.

  In the optical component 1 shown in FIG. 3, the first optical collimator 10 and the second optical collimator 20 are arranged to face each other such that the joint end faces 11 a and 21 a of the collimating lenses 11 and 21 face each other. . The optical functional element 2 is disposed so as to be inserted between the joint end surface 11 a of the collimator lens 11 of the first optical collimator 10 and the joint end surface 21 a of the collimator lens 21 of the second optical collimator 20.

As the optical functional element 2, for example, an optical filter made of a dielectric multilayer film or the like can be used.
In general, the dielectric multilayer filter is composed of a dielectric material such as SiO ₂ , TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O _{5, and the} like with a high refractive index component and a low refractive index component (or three or more kinds of dielectrics). Body) is appropriately selected and used, and several to several hundred layers are laminated in a predetermined film thickness and in a predetermined order. The dielectric multilayer filter can realize various optical characteristics according to the type, film thickness, order, etc. of the dielectric. For example, a filter element having a property of reflecting light of a predetermined wavelength band and transmitting light of another predetermined wavelength band can be used as an optical multiplexing / demultiplexing element.
When an optical multiplexer / demultiplexer is used as the optical functional element 2, the optical component 1 can be used as an optical multiplexer / demultiplexer.

In the optical component 1 shown in FIG. 3, one optical functional element 2 is disposed so as to straddle between a plurality of pairs of collimating lenses. As a result, the number of optical functional elements 2 can be reduced and the cost can be reduced. As an example of the dimensions of the optical functional element 2, for example, when the optical fiber diameter is 125 μm, the lens diameter is 250 μm, and the lens length is 1.0 mm, a = 0.5 mm, b = 1.3 mm, c = 0.5 mm optical functional element 2 (see FIG. 3) can be used.
In addition, an optical functional element can also use a separate element for every pair of lenses comprised of the collimating lens 11 of the first optical collimator 10 and the collimating lens 21 of the second optical collimator 20 facing each other.

According to the optical multiplexer / demultiplexer (optical component) 1 configured as described above, each optical fiber 25 of the second tape fiber 24 of the second optical collimator 20 is similar to the optical multiplexer / demultiplexer shown in FIG. , 25,... Are A ports, and each optical fiber 23, 23,... Of the first tape fiber 22 of the second optical collimator 20 is B port, and each optical fiber of the tape fiber 12 of the first optical collimator 10 is. 13, 13,... Function as C ports.
Here, the positions at which the optical fibers 13, 23, 25 serving as the ports A to C are connected to the collimator lenses 11, 21 are B when the light incident from the A port 25 is reflected by the optical multiplexing / demultiplexing element 2. It is determined that the light emitted from the port 23 and incident from the A port 25 is emitted from the C port 13 when passing through the optical multiplexing / demultiplexing device 2. In this optical component 1, the collimating lens and the optical fiber are accommodated and held in an appropriate holder or housing (housing) so that the collimating lenses 11 and 21 and the optical fibers 13, 23 and 25 are maintained in the above-described arrangement. A configuration can also be employed.

Hereinafter, the operation of the optical multiplexer / demultiplexer 1 of this embodiment will be described.
When the wavelength multiplexed light (for example, λ ₁ + λ ₂ ) is incident from the A port 25, this light is irradiated to the optical functional element 2 through the second collimating lens 21, and the optical functional element according to the wavelength. 2 is demultiplexed. The light λ ₁ reflected by the optical functional element 2 is emitted to the B port 23 via the second collimating lens 21, and the light λ ₂ transmitted through the optical functional element 2 is transmitted to the C port via the first collimating lens 11. 13 is emitted.
Conversely, when light having a wavelength λ ₁ is incident on the B port 23 and light having a wavelength λ ₂ is incident on the C port 13, the light λ ₁ and λ ₂ are combined by the optical functional element 2, and A The light is emitted from the port 25 as wavelength-multiplexed light (λ ₁ + λ ₂ ).

When introducing (adopting) the optical collimator or optical component of the above-described embodiment into an optical communication system using a tape fiber, the tape fiber of the optical communication system and the optical collimator of the present invention or the tape fiber of the optical component are fusion-connected. Only available.
Since the optical fiber taped in advance is connected to the collimating lens, it does not take time to tape the optical fiber as in the prior art, and is excellent in workability.
In addition, since a plurality of collimating lenses are arranged in each optical collimator, a smaller optical functional element can be used. In addition, since the number and size of expensive optical functional elements can be suppressed, material costs and manufacturing costs can be reduced, and the cost of optical components can be reduced.

By downsizing the optical collimator, it is possible to reduce the size and density of the optical component.
According to the optical collimator configured by directly fusion-connecting the collimating lens mainly composed of quartz glass with the end face of the optical fiber of the tape fiber, a smaller and lower loss optical collimator can be realized.

  The optical collimator and the optical component of the present invention can be used for various components used in the optical communication field and the optical measurement field, for example.

It is a schematic block diagram which shows an example of the optical collimator of this invention. It is a schematic block diagram which shows the other example of the optical collimator of this invention. It is (a) schematic block diagram which shows an example of the optical component of this invention, (b) It is a front view. It is a schematic block diagram which shows an example of the conventional optical multiplexer / demultiplexer. It is a schematic block diagram which shows an example of the conventional optical multiplexing / demultiplexing module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical component, 2 ... Optical functional element, 10 ... Optical collimator, 11 ... Collimating lens, 12 ... Tape fiber, 13 ... Optical fiber (C port), 13a ... End face of optical fiber, 20 ... Optical collimator, 21 ... Collimator Lens, 21b ... End face of collimating lens, 22 ... First tape fiber, 23 ... Optical fiber (B port), 23a ... End face of optical fiber, 24 ... Second tape fiber, 25 ... Optical fiber (A port), 25a: End face of the optical fiber.

Claims (4)

  An optical collimator comprising: a tape fiber formed by collectively covering a plurality of optical fibers; and a plurality of collimating lenses connected to end faces of the respective optical fibers of the tape fiber.   A plurality of collimating lenses connected to end faces of the respective optical fibers of the tape fiber, the collimating lenses being the same; An optical collimator, wherein one of the optical fibers of the first tape fiber and one of the optical fibers of the second tape fiber are connected to an end face on the side.   3. The optical collimator according to claim 1, wherein the collimating lens is mainly composed of quartz glass, and an end face of the optical fiber and the collimating lens are directly fused and connected.   The optical collimator according to claim 1, another optical collimator arranged to face the optical collimator, and an optical functional element inserted between the optical collimators. Optical parts.

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