JP2005070368A - Optical multiplexer/demultiplexer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical multiplexer/demultiplexer that can be easily assembled in the reduced number of processes, in a multiple level structure for arraying filters in selecting optical signal wavelengths, that can be easily and precisely aligned in optical systems, and that can be small-sized through a simple structure as well as advantageous costwise. <P>SOLUTION: This optical multiplexer/demultiplexer is constituted such that a waveguide array 1 forms optical waveguides Ei in lines on a substrate 10 of glass or the like and that the levels of a wavelength selecting stage are each connected by such plurality of waveguides Ei. The substrate 10 is structured so that the proximity to the end of each waveguide Ei is formed in a reflection area at 45° angle and that the optical path with the end of each waveguide Ei is changed at 90° to match with light in the thickness direction of the substrate. In this waveguide array 1, there are arranged successively in superposition a lens array Bx, a filter Fi, a lens array Ax and a fiber array Px, making each level of the wavelength selecting stage. In the waveguide array 1 and the lens arrays Ax, Bx, a position marker 2 is installed for the purpose of positioning. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical multiplexer / demultiplexer that superimposes and separates so-called wavelength-multiplexed optical signals, and more specifically, employs a multi-stage configuration in which filters for wavelength selection of optical signals are arranged. And improvement of the arrangement of each stage.

  As for optical communication, wavelength multiplexing communication technology for multiplexing and transmitting optical signals of different wavelengths is well known, and is actively developed for ultra-large capacity. In the wavelength multiplexing communication system, a technique for superposing and separating optical signals is indispensable, and various systems for optical multiplexer / demultiplexers have been proposed.

  There are many methods for wavelength selection in the optical multiplexer / demultiplexer. As an example, there are a method using a multilayer filter for selecting a wavelength, a method using a fiber grating that periodically irradiates an optical fiber with an excimer laser, and a method using wavelength dispersion of an arrayed waveguide. For example, Patent Document 1 proposes a method using a filter for selecting a wavelength.

  As shown in FIG. 1, the optical multiplexer / demultiplexer using the filter has a multistage configuration in which optical systems are arranged corresponding to the wavelengths λi of the optical signal, and each stage i has a port Pi of the optical signal, A filter Fi that transmits the wavelength λi and reflects the light of the wavelengths λ1 to λi−1 is provided, and collimating lenses Ai and Bi are provided before and after the filter Fi, respectively. The collimator lens Bi on the rear side of the filter Fi is connected to the other stage, and two connection ports are provided at a position shifted from the lens main axis toward the collimator lens Bi, and one is a connection port Ci-1 with the previous stage. The other is a connection port Di + 1 to the next stage, and an optical fiber is connected to each of the connection ports to connect to the other stage. Therefore, each stage starts from the port P2, and the port P1 corresponding to the wavelength λ1 is one connection port C1 facing the port P2.

  An optical fiber is connected to each of the ports P1,..., Pn, and optical signals having wavelengths λ1,. The wavelength λ1 incident from the port P1 passes through the collimating lens B2 and becomes parallel light, and travels toward the fill evening F2. Since the filter F2 transmits the wavelength λ2 and reflects the wavelength λ1, the wavelength λ1 from the port P1 side is reflected and returns to the port P1 side. Here, since the port P1 is shifted from the principal axis of the collimating lens B2, the wavelength λ1 reflected and returned is condensed on the connection port D3 with the next stage. On the other hand, the wavelength λ2 emitted from the port P2 passes through the collimator lens A2 and becomes parallel light, passes through the filter F2, and is condensed at the connection port D3 with the next stage. Therefore, the two wavelengths λ1 and λ2 pass through the connection port D3 with the next stage, and the combined optical signal goes to the next stage (connection port C2).

  The same operation is performed at the next stage, and the combined wavelengths λ1 and λ2 emitted from the connection port C2 are reflected by the fill lens F3 through the collimating lens lens B3 and returned to the port C2 side to be connected to the next stage at the shift position. Condensed to port D4. The wavelength λ3 emitted from the port P3 passes through the collimator lens A3, passes through the filter F3, and is condensed on the connection port D4 with the next stage. Therefore, the connection port D4 with the next stage has three wavelengths λ1, The optical signal combined with λ2 and λ3 passes and goes to the next stage (connection port C3).

  By repeating the above, in the final stage, the optical signal combined with the wavelengths λ1,..., Λn passes through the final connection port Dn + 1, and the optical signal combined with all wavelengths is output.

On the contrary, when the optical signal obtained by combining all the wavelengths λ1,..., Λn is incident from the final connection port Dn + 1, the wavelengths λn,. λ1 is condensed, and each wavelength can be extracted and demultiplexed.
JP-A-11-281903

  However, since the optical multiplexer / demultiplexer using the filter described above has a multi-stage configuration in which optical systems are arranged corresponding to the wavelength λi of the optical signal, the number of components increases according to the number of stages, and these are assembled. There is a problem that man-hours are required for manufacturing. Then, the optical system must be aligned at each stage. If the number of stages increases, the man-hours for optical axis alignment become very large, which is complicated and expensive.

  Of course, there is a demand for miniaturization as an optical device, and each element is miniaturized. However, it is not easy to assemble and align microparts in multiple stages, resulting in poor workability and high yield. There is nothing good in terms of manufacturing.

  The present invention has been made in view of the above-described background, and the object of the present invention is to solve the above-described problems and reduce the number of man-hours in a multi-stage configuration in which filters for wavelength selection of optical signals are arranged. It is an object of the present invention to provide an optical multiplexer / demultiplexer that can be easily assembled, can be easily aligned with an optical system, can be obtained with high accuracy, can be downsized with a simple configuration, and is advantageous in terms of cost.

  In order to achieve the above-described object, in the optical multiplexer / demultiplexer according to the present invention, the optical signal having a plurality of different wavelengths is superposed on one another, and the combined optical signal is converted into an optical signal having each wavelength again. The optical signal is arranged in multiple stages corresponding to the wavelength λi of the optical signal, and each stage i transmits the optical signal port Pi and the wavelength λi from the wavelength λ1. a filter Fi that reflects the light of λi−1, collimating lenses Ai and Bi are provided in front of and behind the filter Fi, respectively, and the collimating lens Bi on the rear side of the filter Fi is connected to the other stage. Two connecting ports facing the lens Bi are provided at a position shifted from the lens main axis, one is a connecting port with the previous stage, the other is a connecting port with the next stage, and an optical path is connected to each of the connecting ports. Connect In the optical multiplexer / demultiplexer, a plurality of the collimating lenses are arranged in a line to form a lens array, and light serving as an input / output port of light having wavelength λi and light having wavelengths λ1,. A plurality of fibers are formed in a row to form a fiber array, and the optical path connecting the lenses is formed as a waveguide array by forming a plurality of fibers in a row on a substrate such as glass as a light waveguide. The waveguide array is provided with light guide means for matching the light in the thickness direction of the substrate at the end of each waveguide, and the lens array is arranged so as to overlap the waveguide array.

  The light guide means may be configured such that the vicinity of the end portion of each waveguide in the waveguide array is ground at 45 ° or is ground and polished, and a reflective film is provided on the surface. Further, the lens array and the waveguide array can be integrally formed on the same substrate. Further, it is more preferable that a position marker is provided on each of the lens array and the waveguide array, and that the position markers are aligned to align each collimating lens and each waveguide.

  Each lens of the lens array can be formed by an ion exchange method, a dry etching method, or a mold transfer method. Each lens of the lens array can be formed by a manufacturing method in which a resin is heat-melted to obtain a hemispherical shape due to surface tension, or a manufacturing method in which the resin is dropped and solidified by a microdispenser. Each waveguide of the waveguide array can be formed by an ion exchange method, a polymer formation method, a flame deposition method, or a CVD method.

  In the present invention, a plurality of elements such as waveguides and collimating lenses are formed in an array to form an array part, so that each element in the array part such as a waveguide array or a lens array is correctly arranged in a predetermined position. Can be obtained. In addition, since a position marker is provided on an array component such as a waveguide array or a lens array, it can be correctly assembled by using this as a reference.

  In addition, since the waveguide array is provided with light guide means for aligning the light in the thickness direction of the substrate with respect to each waveguide, other components such as a lens array can be sequentially stacked on the waveguide array. . Therefore, since the other components are arranged facing the waveguide array, the configuration becomes compact.

  In the optical multiplexer / demultiplexer according to the present invention, a plurality of elements, such as waveguides and collimating lenses, are formed in an array to form an array part, so that each element in the array part is properly arranged in a predetermined position. Can get to. In addition, since a position marker is provided on an array component such as a waveguide array or a lens array, it can be correctly assembled by using this as a reference. As a result, it can be easily assembled with a small number of man-hours, and it is not necessary to align each element individually as in the prior art, and the optical system can be easily aligned and obtained with high accuracy.

  In addition, since the waveguide array is provided with light guide means for aligning the light in the thickness direction of the substrate with respect to each waveguide, other components such as a lens array can be sequentially stacked on the waveguide array. . Accordingly, since other components are arranged facing the waveguide array, the configuration becomes compact, and the size can be reduced by a simple configuration, which is advantageous in terms of cost.

  2 and 3 show a first embodiment of the present invention. In the present embodiment, the optical multiplexer / demultiplexer has a multi-stage configuration in which optical systems are arranged corresponding to the wavelength λi of the optical signal, and each stage i includes a port Pi, a collimating lens Ai, a filter Fi, and a collimating lens. Bi is arranged in order, and a plurality of these are arranged in an array for each element to form an array part, and the array parts are assembled in order.

  That is, as shown in FIG. 2B, the optical multiplexer / demultiplexer is assembled by sequentially superimposing the lens array Bx, the filter Fi, and the lens array Ax on the waveguide array 1 serving as an optical path connected to the other stages. The fiber array Px is assembled so as to face the lens array Ax. Since these are provided at each end of the waveguide Ei of the waveguide array 1, two sets are assembled on the waveguide array 1. Further, the optical multiplexer / demultiplexer of this embodiment is configured to input / output five waves up to wavelengths λ1,..., Λ5, one of the two sets on the waveguide array 1 is the λ1, λ3, λ5 side, and the other is λ2. , Λ4, λa side.

  In the waveguide array 1, optical waveguides Ei are formed in a row on a substrate 10 such as glass, and the respective stages are connected by the plurality of waveguides Ei. As shown in FIG. 3, each waveguide Ei is formed by photolithography with both ends of the belt-like pattern positioned at a predetermined condensing point. The waveguide array 1 is provided with a position marker 2 for alignment.

  The substrate 10 of the waveguide array 1 is provided with a reflective film 11 by grinding or polishing the side edge to a 45 ° inclined surface on the side where the end of each waveguide Ei faces. That is, the vicinity of the end portion of each waveguide Ei is formed on a 45 ° reflection surface, and the optical path to the end portion of each waveguide Ei is converted by 90 ° to match the light in the thickness direction of the substrate 10. Accordingly, these serve as light guide means for guiding the alignment of light, and in the waveguide array 1, the lens array Bx, the fill film Fi, the lens array Ax, and the fiber array Px can be arranged in this order.

  Each waveguide Ei of the waveguide array 1 can be formed by various methods. For example, the waveguide Ei can be formed by an ion exchange method, a polymer forming method, a flame deposition method, or a CVD method.

  In the present embodiment, the lens arrays Ax and Bx are formed by arranging three collimating lenses Ai and Bi in a line and arranging the two pairs on the waveguide array 1. More specifically, one is an array in which the lens array B135 and the lens array A135 face each other, and the other is an array in which the lens array B24a and the lens array A24a face each other.

  The lens arrays Ax and Bx are formed by photolithography, and position markers 2 are provided at both ends of the array of collimating lenses Ai and Bi. The collimating lenses Ai and Bi of the lens arrays Ax and Bx may be formed by, for example, an ion exchange method, a dry etching method, or a mold transfer method. The lenses Ai and Bi of the lens arrays Ax and Bx can also be formed by a manufacturing method in which a resin is melted to obtain a hemispherical shape by surface tension, or a method in which the resin is dropped and solidified by a microdispenser. .

  In this embodiment, the fiber array Px is formed by arranging three ports in a line and arranging them on the waveguide array 1, with one being an array of ports P1, P3, and P5 and the other being a port. The arrangement is P2, P4, and Pa.

  The filter Fi has a characteristic of transmitting the wavelength λi and reflecting the light having the wavelengths λ1 to λi−1, and is formed on the glass plate. The filter Fi is disposed between the lens array Bx and the lens array Ax, but is not necessary for the first and last stages, that is, not disposed at positions facing the ports P1 and Pa.

* Multiplexing operation and demultiplexing operation As described above, the configuration in which each array component is assembled on the waveguide array 1 in order is as shown in FIG. 4 when the optical system is viewed from the side of each port Pi. This is substantially the same as the multistage configuration shown in FIG.

  That is, an optical fiber is connected to each of the ports P1,..., P5, and optical signals having wavelengths λ1,. The wavelength λ1 incident from the port P1 passes through the lens A1, and no filter is disposed on the λ1 stage. Therefore, the wavelength λ1 passes through the collimating lens B1 facing the light as it is, and is collected and reflected by the reflection film 11 of the substrate 10. The light enters the waveguide E1 that matches the reflected light. Furthermore, this wavelength λ1 is emitted from the other end through the waveguide E1, reflected by the reflective film 11, and then directed to the next stage (λ2 stage).

  The reflected light enters the collimating lens B2 from a position shifted from the lens main axis and travels toward the fill evening F2. Since the film evening F2 reflects the wavelength λ1 and transmits the wavelength λ2, the light from the waveguide E1 is reflected back by the film evening F2 and again passes through the collimating lens B2 to be connected to the next stage (λ3 stage). Condensed to the waveguide E2. Then, the wavelength λ2 emitted from the port P2 passes through the collimating lens A2, the filter lens F2, and the collimating lens B2 in order, and is condensed on the waveguide E2 whose optical path is aligned. , And the combined optical signal goes to the next stage (λ3 stage).

  In this way, the wavelengths λ1,..., Λ5 from the ports P1,. The wavelengths λ1,..., Λ5 are collected at the port Pa of the stage, and an optical signal obtained by combining all wavelengths is output.

  On the other hand, when the demultiplexing operation is reversed, when an optical signal obtained by combining all the wavelengths λ1,..., Λ5 is emitted from the port Pa at the last stage, the ports P1,. The wavelengths λ1,..., Λ5 are condensed and the wavelengths can be extracted and demultiplexed.

  Thus, since a plurality of elements such as the waveguide Ei and the collimating lenses Ai and Bi are formed in an array to form an array part, an array such as the waveguide array 1, the lens arrays Ax and Bx, and the fiber array Px is provided. Each element in the part can be obtained in a state of being correctly arranged in a predetermined position. Further, since the position marker 2 is provided on the array components such as the waveguide array 1 and the lens arrays Ax and Bx, it can be correctly assembled by using this as a reference.

  As a result, it can be easily assembled with a small number of man-hours, and it is not necessary to align each element individually as in the prior art, and the optical system can be easily aligned and obtained with high accuracy.

  In addition, since the waveguide array 1 is provided with light guide means for matching the light in the thickness direction of the substrate 10 with respect to each waveguide Ei, the other components (lens array Bx, fill filter Fi, lens array Ax, The fiber array Px) can be assembled on the waveguide array 1 in order. Therefore, since other components are arranged facing the waveguide array 1, the configuration becomes compact, and the size can be reduced by a simple configuration, which is advantageous in terms of cost.

  5 and 6 show a second embodiment of the present invention. As in the first embodiment, the second embodiment employs a configuration that inputs and outputs five waves up to wavelengths λ1,. In this embodiment, the collimating lens Ai forms two arrays of three rows on the base plate to form one array component (lens array 3), and the collimating lens Bi is located on the waveguide array 4 side. Two rows of three are integrally formed. The other components are the same as those of the first embodiment described above, and the same reference numerals are given and the description thereof is omitted. In this case, there are two array parts, a lens array 3 and a waveguide array 4, and a filter Fi is disposed between them to overlap each other.

* Positioning in Overlapping Direction As shown in FIG. 5B, the waveguide array 4 and the lens array 3 are provided with an abutting portion 5 on the opposing surfaces of the both, and the abutting portion 5 is attached when they are superimposed. It is the structure which touches. The abutting portion 5 can be formed by leaving the surface in photolithography for forming the collimating lenses Ai and Bi, and serves as a reference surface at the height position.

  In other words, since the filter Fi is formed on a glass plate, the plane accuracy is sufficiently high, and the abutting portion 5 is brought into contact with the surface at the time of assembly. Therefore, the waveguide array 4, the filter Fi, and the lens array 3 are simply stacked. The position and the tilt position are aligned in a predetermined manner, and the assembly is completed.

  Thus, by forming the collimating lens Bi directly on the waveguide array 4 side, there is an advantage that a part of the alignment work at the time of manufacturing can be omitted.

  In the present embodiment, as described above, there are two array parts, alignment can be performed by simply superimposing the waveguide array 4, the filter Fi, and the lens array 3, and the assembly is completed. Therefore, the number of alignment steps can be further reduced. Therefore, the effect of reducing the cost is great, the configuration is further simplified, and the size can be further reduced.

It is a block diagram which shows the prior art example of an optical multiplexer / demultiplexer. It is the top view (a) and sectional drawing (b) of the optical multiplexer / demultiplexer which show 1st Embodiment. FIG. 3 is a plan view of the waveguide array shown in FIG. 2 viewed from the lens array side. It is a block diagram of the optical multiplexer / demultiplexer shown in FIG. It is the top view (a) and sectional drawing (b) of the optical multiplexer / demultiplexer which show 2nd Embodiment. It is the top view which looked at the waveguide array shown in FIG. 5 from the lens array side.

Explanation of symbols

1, 4 Waveguide array 2 Position marker 3, Ax, Bx Lens array 5 Abutting portion 10 Substrate 11 Reflective film Ai, Bi Collimator lens Fi Filter Ei Waveguide Pi Port Px Fiber array

Claims (5)

A combination of superposing a plurality of optical signals of different wavelengths into one, and a demultiplexing of the combined optical signal into optical signals of the respective wavelengths again,
The optical system is arranged in multiple stages corresponding to the wavelength λi of the optical signal,
Each stage i has an optical signal port Pi and a filter Fi that transmits the wavelength λi and reflects the light of the wavelengths λ1 to λi−1.
Collimating lenses Ai and Bi are provided before and after the filter Fi,
The collimator lens Bi on the rear side of the filter Fi is connected to the other stage,
Two connection ports are provided at a position shifted from the lens main axis toward the collimating lens Bi, one of which is a connection port with the previous stage and the other is a connection port with the next stage. In the optical multiplexer / demultiplexer connected to the stage,
A plurality of collimating lenses are formed in a line to form a lens array;
A plurality of optical paths are formed in a row on a substrate such as glass as light waveguides to form a waveguide array. The waveguide array includes light in the thickness direction of the substrate at the end of each waveguide. An optical multiplexer / demultiplexer characterized in that a light guide means for matching is provided, and the lens array is disposed so as to overlap the waveguide array.   2. The light guide means according to claim 1, wherein the vicinity of the end of each waveguide in the waveguide array is ground at 45 ° or is ground and polished, and a reflective film is provided on the surface. Optical multiplexer / demultiplexer.   The optical multiplexer / demultiplexer according to claim 1, wherein the lens array and the waveguide array are integrally formed on the same substrate.   The collimating lens and each waveguide are aligned with each other by providing a position marker on each of the lens array and the waveguide array, and aligning the position markers. Optical multiplexer / demultiplexer.   5. The optical multiplexer / demultiplexer according to claim 1, wherein each lens of the lens array is formed by a manufacturing method in which a resin is thermally melted to obtain a hemispherical shape by surface tension.

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