JP2005274700A - Optical multiplexer/demultiplexer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical multiplexer/demultiplexer with which an increase or the like in the assembling time accompanied by centering operation is solved. <P>SOLUTION: The optical multiplexer/demultiplexer has a lens array block 10 comprising a plate-like block body 56, convex lenses 1-4 formed on one surface of the block body 56 and beam branching elements 11-14 held on a lens array face and on the optical paths of beams passing respective convex lenses 1-4 by respective holding structures 5-9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical multiplexer / demultiplexer that multiplexes / demultiplexes an optical signal, and is used, for example, as an optical communication module used for optical communication.

  FIG. 13 is a schematic configuration diagram of an example of a conventional optical multiplexer / demultiplexer. As shown in the figure, the conventional optical multiplexer / demultiplexer includes a first lens member 10 and a second lens member 11 which are arranged to face each other.

  The first lens member 10 is a plate-shaped transparent body, and a plurality of lens surfaces 101 </ b> A to 104 </ b> A are formed in a row on one surface of the plate-shaped transparent body, and the surface facing the second lens member 11. , The inclined surfaces 101B to 104B are formed in a line corresponding to the lens surfaces 101A to 104A on a one-to-one basis.

  The second lens member 11 is a plate-like transparent body, and a plurality of lens surfaces 111 </ b> A to 114 </ b> A are formed in a row on one surface of the plate-like transparent body, and the surface facing the first lens member 10. In the lens surfaces 111A to 114A, the inclined surfaces 111B to 114B are formed in a line corresponding to the lens surfaces 111A to 114A.

  A transparent filter film F is formed on the inclined surface 101B of the first lens member 10, and reflective films RF2 to RF4 are formed on the other inclined surfaces 102B to 104B, respectively. In addition, filters SR1 to SR4 are formed on the inclined surfaces 111B to 114B of the second lens member 11, respectively.

  The inclination direction of the inclined surfaces 101B to 104B in the first lens member 10 and the inclination direction of the inclined surfaces 111B to 114B in the second lens member 11 are obtained by converting the optical signal incident on the optical multiplexer / demultiplexer into one lens member. Each of the inclined surfaces is sequentially reflected from one lens member to the other lens member.

  The case where the light beam radiated from the optical port P0 to the first lens member 10 is demultiplexed by the second lens member 11 and output from the optical ports P1 to P4 will be described.

  First, when wavelength multiplexed light is incident on the first lens member 10 from the optical port P0, the wavelength multiplexed light is converted into parallel light by the lens surface 101A, passes through the transparent filter film F, and then enters the filter SR1. The wavelength multiplexed light that has entered the filter SR1 transmits only light in a specific wavelength range, and reflects light in other wavelength ranges. The light beam reflected by the filter SR1 is rereflected by the reflection surface RF2 and enters the filter SR2.

  In this way, after the light beam is incident on each of the filters SR1 to SR4, only the light beam in a specific wavelength region is transmitted and the operation of reflecting the light beam in the other wavelength region is repeated, whereby each of the filters SR1 to SR4 is made. The transmitted light in the wavelength range is re-condensed by the lens surfaces 111A to 114A, and the demultiplexed monochromatic light is output from the optical ports P1 to P4, respectively.

  Conversely, by inputting monochromatic rays having different wavelength ranges to the optical ports P1 to P4, wavelength multiplexed rays obtained by combining a plurality of monochromatic rays are output from the optical port P0.

  However, the conventional optical multiplexer / demultiplexer described above has several problems.

<It is necessary to align the optical port with the lens member>
In the conventional optical multiplexer / demultiplexer, the inclined surfaces 101B, 111B, etc. and the lens surfaces 101A, 111A, etc. are formed on both surfaces of a single glass member. For this reason, it is difficult to integrally form a structure for positioning the optical port P0 and the like on the lens surface side. Therefore, since it is necessary to position the optical port separately with respect to the lens member, alignment work is required, and there is a problem that assembly time increases.

<Smoothness of the entire inclined surface to which the filter is attached is required>
In the conventional optical multiplexer / demultiplexer, the surfaces of the inclined surfaces 111B and the like of the lens member to which the filter SR1 and the like are attached are in contact with the entire surface of the filter SR1 and the like. Since this contact surface corresponds to the optical path of propagating light, high smoothness and refractive index matching are required. Therefore, there is a problem that the processing cost of the lens member increases.

<Spherical aberration increases because the diffused light side is a lens surface>
In general, when a light beam from a point light source is converted into a parallel beam, it is desirable to dispose the lens so that the refraction of the peripheral beam is as small as possible. This is to avoid an increase in spherical aberration. Therefore, in order to reduce spherical aberration using a plano-convex lens, it is desirable to arrange a lens curved surface on the parallel light side and a lens plane on the point light source side. However, since the conventional optical multiplexer / demultiplexer has a curved lens surface on the optical port side, spherical aberration increases. Therefore, there is a problem that loss increases.

<It is necessary to offset the optical axis positions of the lens surfaces of the two lens members>
In the conventional optical multiplexer / demultiplexer, one medium is air and the other medium is a glass member with the filter SR1 and the like interposed therebetween. For this reason, the propagating light beam is refracted when entering the glass member from the air through the filter or entering the air from the glass member through the filter. Therefore, in order not to cause an excessive loss due to the optical axis shift, the lens surface optical axis positions of the two lens members must be slightly offset, and there is a problem that alignment and assembly time increase.

<Thickness of lens member is determined by member strength and transmission loss, and optical path length is limited>
In the conventional optical multiplexer / demultiplexer, the light beam that propagates between the lens surface 111A and the like and the filter SR1 and the like passes through the inside of the glass member. For this reason, it is necessary to reduce the thickness of the lens member in order to reduce the propagation loss. However, if the thickness is excessively thin, it is difficult to precisely process both surfaces of the lens member and maintain the strength thereafter. It becomes. Therefore, there is a problem that the degree of freedom in designing the thickness of the lens member is reduced, and the optical path length between the lens surface and the filter surface is restricted.

  The present invention has the problems as described above, that is, (1) an increase in assembly time associated with the alignment operation of the optical port, (2) an increase in processing cost of the lens member due to smooth inclined surface processing, and (3) a lens. The object is to solve problems such as an increase in optical loss due to the arrangement method of the surface, (4) an increase in assembly time due to the offset work, and (5) restrictions on the optical path length.

<First invention>
The optical multiplexer / demultiplexer according to the first invention is
A plate-shaped block body;
One or more convex lenses formed on one surface of the block body;
A holding structure that is formed on the block main body and that determines the position and angle of one or a plurality of light branching elements on the optical path of the light passing through each convex lens and on the same surface side as the one-side surface is integrally formed. An optical multiplexer / demultiplexer having a lens array block.

<Description of configuration and explanation of specific examples>
An optical multiplexer / demultiplexer is a device having a function of combining, for example, a plurality of monochromatic light beams into one wavelength multiplexed light beam and a function of branching, for example, a single wavelength multiplexed light beam into a plurality of monochromatic light beams. Further, the light beam splitting element is an element that transmits a light beam in a specific wavelength region among incident light beams and reflects a light beam in other wavelength regions.

  Specific examples of beam splitters in the case of using a specific wavelength range fixedly include a bandpass filter using a dielectric multilayer film, an edge filter, and a fine grating structure with a wavelength order periodically formed on the surface. A resonance mode filter or the like can be considered.

  In addition, the wavelength range to be transmitted can be changed independently for each beam splitter by external control. In that case, a wavelength tunable filter using the electro-optic effect or thermo-optic effect, or MEMS technology is used. An etalon filter or the like can be considered.

  Naturally, there may be a case where the wavelength range that transmits the light beam splitting element includes the entire wavelength range of the incident light beam. In this case, the light beam splitting element corresponds to an optical transmission window. On the contrary, a light beam splitting element that does not transmit all the wavelength ranges of incident light has a function equivalent to a planar reflecting surface.

  The wavelength spectrum width of monochromatic light is basically determined by the laser diode that is the light source, but if it passes through a wavelength selection filter or the like in the middle of transmission of the optical signal, it is corrected by the transmission spectrum of the wavelength selection filter. Is done.

  When the present invention is used as an optical demultiplexer, a plurality of externally input signals are incident on the inside as a single wavelength-multiplexed beam, and propagate through the interior by sequentially entering and reflecting each beam branching element. . At this time, the monochromatic light beam transmitted through each light beam branching element is coupled to a light receiving element such as an optical fiber or a photodiode, and is output again as a plurality of signals.

  On the other hand, when the present invention is used as an optical multiplexer, a plurality of signal lights input from the outside are transmitted by separate optical fibers or photoelectrically converted by separate light emitting elements such as laser diodes, Are input as monochromatic rays. These monochromatic light beams are introduced into each of the light beam splitting elements that are designed to transmit the wavelength range, and are then introduced into the respective light beams. Propagating inside while being combined sequentially. Then, after finally being combined into one wavelength multiplexed light beam, it is coupled to a light receiving element such as an optical fiber and is output to the outside again.

  In general, in the process of multiplexing / demultiplexing, optical systems and elements are designed so that the wavelength ranges of a plurality of monochromatic rays do not overlap each other. Also, an optical lens system etc. on the optical path connecting the light emitting / receiving point and the light beam splitting element for the purpose of efficiently coupling the light beam with the optical fiber or the light receiving / emitting element or converting the diffused light beam into a collimated light beam, etc. May be arranged. The first invention is characterized in that the structure for holding the optical lens system and the beam splitter is integrated on the same surface.

<Description of operation>
In the optical system of the optical multiplexer / demultiplexer, there is a problem that if the position and angle at which the beam splitter is arranged deviate from the design value, the coupling efficiency is lowered and the optical axis of the propagating beam is shifted. It is necessary to pay particular attention to the deviation of the arrangement angle and the deviation of the optical path length connecting the beam splitter and the lens.

  This is because the displacement of the arrangement angle causes an optical axis shift when the reflected light from the light beam splitting element enters another light beam splitting element, and the optical path length shift is the light beam transmitted through the light beam splitting element at the light receiving point. This is to cause a defocus when combining.

  In the first invention, in order to accurately and easily determine the arrangement angle and the optical path length, structures such as protrusions and depressions for holding the lens and the beam branching element are integrally formed in one lens array block. Is a feature. Furthermore, since the beam branching element holding structure and the lens curved surface are formed on the same surface of the lens array block, the opposite surface of the lens array block can be a uniform plane.

  Therefore, a block for arranging and fixing a light emitting / receiving element such as an optical fiber can be integrally formed on the uniform plane side of the lens array block.

  In addition, it is desirable to form an antireflection film for suppressing the Fresnel loss in the region where the propagating light beam is transmitted among the surfaces on both sides of the lens array block. Further, as the beam branching element holding structure, a structure that can fix the beam branching element of each channel independently is desirable. Assuming that a general-purpose filter chip with a standardized size and transmission spectrum is assumed as a beam splitter, an optical multiplexer / demultiplexer having an arbitrary multiplexing / demultiplexing spectrum can be reduced by simply replacing these chips. This is because it can be realized.

The effects of the first invention are as follows.
<Relative position and angle of beam splitter and lens can be positioned accurately and easily>
The structure and lens for accurately placing and fixing the light branching element are formed in one lens array block in advance, so that the light branching element can be assembled simply by pressing, butting and bonding. . That is, it is possible to arrange the beam branching elements with high accuracy and easily fix them without requiring any special mounting device or skill.

  Furthermore, since it is not necessary to prepare lenses for the number of channels separately, the number of parts can be reduced. Further, since all the lenses are integrated as a lens array block made of the same material, the thermal expansion coefficients of all the lenses are the same, and the deterioration of the optical characteristics accompanying the change in the environmental temperature can be suppressed.

<Easy injection molding because the microstructure is only on one side when molding the block>
When manufacturing a lens array block by injection molding using a mold, when forming the lens curved surface and the beam branching element holding structure on separate surfaces, there are at least two complicated molds corresponding to each surface shape. is necessary. On the other hand, in the present invention in which a complicated fine structure such as a lens curved surface and a beam branching element holding structure is formed on the same surface, a single complicated mold can be used. Therefore, the part manufacturing cost can be reduced.

<The beam branching element holding structure and the beam branching element have a narrow surface>
When the structure for determining the arrangement angle of the beam splitter is formed integrally with the lens array block, if the entire surface of the beam splitter is brought into surface contact with the surface of the lens array block, the contact surface corresponds to the optical path of the propagating beam. Therefore, high smoothness is required.

  On the other hand, in the first invention, since the structure for arranging the beam branching element is formed on the lens forming surface side of the lens array block, it cannot be brought into surface contact with the lens array surface. It is necessary to support and arrange and fix a part of the surface of the element. In this case, since the support point does not correspond to the optical path, smoothness is not necessary, and the required processing accuracy is reduced because it is only necessary to form a narrow support surface instead of the entire surface. Thereby, component manufacturing costs can be reduced.

<Use of lens that reduces spherical aberration is possible>
In general, when a diffused light beam from a light emitting point is used as a collimated light beam, spherical aberration increases unless a lens is arranged so as to minimize the refraction of the peripheral light beam. Therefore, when using a plano-convex lens, it is desirable to dispose a lens curved surface on the collimated ray side and a lens plane on the light emitting point side in order to reduce spherical aberration. In the first invention, since such an optical system can be realized, it is possible to reduce spherical aberration and optical loss.

<Because there is no beam tilt due to the difference in refractive index, there is no need to offset the optical axis of the lens>
When the refractive index of the medium in contact with both surfaces of the light branching element is different as in the prior art, a difference in refractive index occurs when the propagating light passes through the light branching element, and the propagating light is refracted. On the other hand, in the first invention, the medium in contact with both surfaces of the beam splitter is the same, generally air, and there is no difference in refractive index. For this reason, the optical axis of the propagating light beam is slightly shifted, but the optical axis is not refracted.

  Therefore, when the optical multiplexer / demultiplexer is constituted by two lens array blocks, the optical axis of the lens surface of the first lens array block for inputting / outputting monochromatic light and the wavelength multiplexing light for inputting / outputting Even if the optical axis of the lens surface of the second lens array block is not offset, excess loss due to optical axis deviation hardly occurs. Therefore, assembly is possible without increasing the alignment and assembly time.

<As for the lens block thickness, only the optical path portion needs to be thinned>
In order to reduce the propagation loss when the light beam passes through the lens, it is necessary to make the lens member as thin as possible. However, if the opposite side of the curved surface of the lens is an inclined surface for holding the beam branching element as in the prior art, it is not easy to reduce the thickness according to the processing accuracy and the inclination angle.

  On the other hand, in the first invention, since the opposite side of the lens curved surface is a uniform plane, it is relatively easy to reduce the thickness. Further, if the portion not corresponding to the optical path is made sufficiently thick, the strength of the lens array block itself can be maintained.

<Second invention>
An optical multiplexer / demultiplexer according to a second invention is the optical multiplexer / demultiplexer according to the first invention,
Further, the light receiving / emitting means fixing block for positioning the light receiving / emitting means for delivering the light to and from the optical multiplexer / demultiplexer is integrally formed on the surface of the lens array block opposite to the lens array surface. It is an optical multiplexer / demultiplexer.

<Description of configuration and explanation of specific examples>
The lens array surface is a surface on which a convex lens in the lens array block is formed. The light receiving / emitting means receives the propagation light inside the optical multiplexer / demultiplexer at the light receiving point and outputs it as a signal to the outside, or emits the signal from the outside of the optical multiplexer / demultiplexer as the light ray at the light emitting point. It is a means for inputting to the inside.

  As specific examples of the light receiving and emitting points, an optical fiber, a tip surface of an optical waveguide, and the like can be considered. For the light receiving point, the light receiving surface of the photodiode, and for the light emitting point, the light emitting surface of the laser diode can be considered. Furthermore, components in which these optical fibers, laser diodes, photodiodes and the like are combined with an optical lens system, that is, a tip fiber, a fiber collimator, a transmission system optical subassembly (TOSA), and a reception system optical subassembly (ROSA). It is also conceivable that a part such as can be regarded as a light emitting / receiving point.

<Description of operation and background>
For example, when the light receiving / emitting point is the tip surface of the optical fiber, if the position or angle at which the optical fiber is disposed with respect to the lens deviates from the design value, the coupling efficiency is lowered and the optical axis of the propagating light beam is shifted. Also, if special equipment and skills are required for alignment work to arrange optical fibers as designed, there is a problem that assembly time and assembly cost increase, and the number of channels of the optical multiplexer / demultiplexer increases. As the number of optical fibers increases, the problem increases. The second invention is characterized in that a light receiving / emitting means fixing block for solving such a problem is integrated with the lens array block.

The effects of the second invention are as follows.
<Precise positioning of light emitting / receiving means, simple fixing, multi-channeling, reduction of parts count>
For example, an optical fiber can be pressed, abutted, and bonded together by previously forming a fixed block with a fixed groove, for example, on the lens array block in order to arrange and fix the light emitting / receiving means as designed. The assembly is completed.

  In other words, the optical fiber can be accurately arranged with respect to the lens, and can be easily fixed without requiring any special alignment device or skill. In this case, since the processing accuracy used for the optical design of the lens and the positioning accuracy of the optical fiber can be realized at substantially the same level, the optical fiber can be arranged and fixed with very high accuracy.

  Further, if a plurality of fixing grooves are formed as necessary, an increase in assembly time can be suppressed even if the number of optical fibers increases. As a result, the relative position and angle of the light emitting / receiving means, the lens, and the light beam splitting element can be accurately and easily determined collectively by one lens array block having the light receiving / emitting means fixing block. The assembly time and cost of the optical multiplexer / demultiplexer can be greatly reduced.

<Third invention>
An optical multiplexer / demultiplexer according to a third invention is the optical multiplexer / demultiplexer according to the first or second invention,
The light branching element is an optical multiplexer / demultiplexer characterized in that a light incident / reflecting surface is tilted and held with respect to the lens array surface.

<Description of operation and background>
In the optical multiplexer / demultiplexer according to the third aspect of the invention, since the multiplexing / demultiplexing operation is performed using the transmitted beam and the reflected beam of the beam splitter, the monochromatic beam incident on the beam splitter (or transmitted through the beam splitter) The optical axis needs to be not perpendicular to the reflecting surface of the beam splitter, but oblique.

  Therefore, a virtual plane (hereinafter referred to as a filter array surface) that can be regarded as having a plurality of intersections between the optical axis of the beam splitter and the beam splitter surface, and each beam splitter reflection surface are parallel to each other. In some cases, the light receiving / emitting surface of the light emitting / receiving means is used in order to make the straight line connecting the light emitting / receiving points of the light emitting / receiving means for monochromatic light (hereinafter referred to as the light receiving / emitting point connecting line) parallel to the filter array surface. It cannot be parallel to the light receiving / emitting point connection line, and must be arranged obliquely. Therefore, when the light emitting point is a laser diode or the like, there arises a problem that it is difficult to arrange the light emitting points in an array.

  On the other hand, in the third invention, the shape of the light beam branching element holding structure formed in the lens array block is devised, and the surface of the light beam branching element with respect to the filter array surface (parallel to the lens array surface). By holding the filter so as to be inclined, it is possible to perform an optical design in which the light receiving / emitting point connecting line and the light receiving / emitting surface of the light receiving / emitting means are parallel while keeping the filter array surface and the light receiving / emitting point connecting line in parallel. .

The effects of the third invention are as follows.
<V-grooves, fiber arrays, and waveguides are easy to apply and can be easily integrated>
When a plurality of light receiving / emitting means are arranged in an array, the light receiving / emitting point connecting line and the light receiving / emitting surface of the light receiving / emitting means are parallel, that is, the light of the light received or emitted by the light receiving / emitting point connecting line and the light receiving / emitting means. Since the axis intersects perpendicularly, general-purpose optical fiber arrays, V-groove arrays for positioning optical fibers, array-shaped optical waveguides, etc. can be used as they are, and the end faces of these members need to be shaped obliquely There is no. Therefore, member cost can be reduced.

  In particular, when the lens array block and the V-groove array block for positioning the optical fiber are integrally formed, it is not necessary to form the V-groove obliquely with respect to the lens array surface. Can be manufactured.

<Easy positioning of light emitting / receiving means>
Also, during alignment work to improve coupling efficiency, there is no need to finely adjust both the position and angle at which the optical fiber or optical waveguide is placed. The placement angle is fixed vertically and only the placement position is finely adjusted. Just adjust. Therefore, the alignment time of the member can be reduced.

  In particular, when the light emitting means arranged in an array is a laser diode, the coupling efficiency is sensitive to the arrangement angle of the light emitting means and the displacement of the arrangement position, but it is possible to omit the adjustment of the arrangement angle. Greatly reduces alignment time.

<Fourth Invention>
The optical multiplexer / demultiplexer according to the fourth invention is the optical multiplexer / demultiplexer according to the first or second invention,
The light beam splitter is an optical multiplexer / demultiplexer characterized in that a light incident / reflecting surface is held parallel to the lens array surface.
According to the fourth aspect of the invention, a single reflecting surface can be used as the reflecting surface installed facing the lens array block.

<Fifth invention>
An optical multiplexer / demultiplexer according to a fifth invention is the optical multiplexer / demultiplexer according to any one of the first to fourth inventions,
An optical multiplexer / demultiplexer characterized in that one or a plurality of reflection / condensing elements are arranged on an optical path until a reflected light beam from a light beam splitting element enters another light beam splitting device.
<Sixth Invention>
An optical multiplexer / demultiplexer according to a sixth invention is the optical multiplexer / demultiplexer according to the fifth invention,
The optical multiplexer / demultiplexer is characterized in that the one or a plurality of reflective condensing elements are integrally formed as a reflective condensing element array block facing the lens array block.

<Description of configuration and explanation of specific examples>
A reflective condensing element is an element that reflects and collects incident light. Specific examples include a concave reflecting surface, a surface on the plane side of a plano-convex lens, and a Fresnel lens principle. A Fresnel mirror that applies the above can be considered. Moreover, a convex lens may be formed in the reflective condensing element array block, or a V-groove or the like for positioning and fixing the light emitting / receiving means may be formed on the back surface.

  In the optical multiplexer / demultiplexer, a light propagation region (hereinafter referred to as an optical waveguide unit) including an optical path where a light beam reflected by a certain light beam branching element enters another light beam branching element is preferably free space. However, in order to arrange all the light branching elements on the same filter array surface, it is necessary to interpose a reflective surface other than the light branching elements in the optical waveguide portion. This corresponds to a case where a part of has a function equivalent to that of the reflective condensing element.

<Description of operation and background>
Due to factors such as the size of the lens arranged in the immediate vicinity of the light emitting / receiving point, the size of the light branching element, or the mounting form of the light receiving / emitting means, there is a lower limit to the arrangement interval of adjacent monochromatic light beams. Therefore, in order to increase the number of channels of the optical multiplexer / demultiplexer or to reduce the light incident angle to the beam splitter for improving the filter characteristics, the optical path length between adjacent beam splitters and the light emitting point to the light receiving point The optical path length needs to be increased.

  However, signal light used in optical communication is generally a Gaussian beam, and as the optical path length increases, the beam diffuses and loss increases. In addition, in order to prevent this increase in loss, even if each lens of the optical multiplexer / demultiplexer is optically designed for each lens closest to the light receiving / emitting point, the optical path length from the lens to the light receiving / emitting point is not uniform in each channel. Another problem occurs.

  These problems can be solved by interposing an optical element having a function of condensing a light beam in the optical waveguide portion to make the beam diameter of the light beam incident on each light beam branching element uniform. In this invention, the reflective condensing element arranged in the optical waveguide section has the function.

The effects of the fifth and sixth inventions are as follows.
When an optical lens system is used as an optical element having a condensing function, propagation loss occurs depending on the material type such as glass or resin. However, when a reflective condensing element is used, light propagates in the air. Propagation loss is almost negligible. Accordingly, loss of optical power can be greatly reduced.

  In addition, when using an optical lens system, it is necessary to select a lens medium according to the wavelength range of the propagating light beam. However, if a reflective condensing element is used, the light beam is reflected by the medium surface and does not pass through the medium. There is no need to consider the refractive index of the medium, and the reflective condensing element can be designed by selecting an arbitrary medium. Therefore, it is possible to greatly improve the degree of freedom in selecting the material to be applied and the surface processing method, and it is possible to realize a reduction in manufacturing cost and an improvement in optical performance.

  Specifically, the following effects can be obtained. When manufacturing an optical lens having a target focal length, it is necessary to design three elements of the lens medium refractive index, the lens thickness, and the paraxial radius of curvature of the lens, and to suppress variations from the respective design values. Therefore, it is difficult to improve the yield of the lens, and it is difficult to measure and evaluate the focal length of the product, which increases the cost.

  On the other hand, when using a reflective condensing element, especially a concave mirror, only the paraxial radius of curvature of the concave surface is designed, and it is only necessary to suppress variations in the paraxial radius of curvature during manufacturing. The focal length of a product can also be evaluated simply by measuring the shape of the concave surface. That is, an optical element having a target focal length can be realized with high accuracy and low cost by using a reflective condensing element rather than an optical lens.

  Furthermore, when using an optical lens system, propagating light passes through both the air and the lens medium, resulting in Fresnel loss at the interface. However, when a reflective condensing element is used, the light does not pass through the medium interface. Therefore, there is no Fresnel loss. Of course, the reflection condensing element also has a reflection loss, but in general, the reflection loss can be easily made smaller than the Fresnel loss.

  Further, in the optical lens system, Fresnel loss occurs on both the incident surface and the exit surface, whereas in the reflective condensing element, reflection loss occurs only on the reflective surface. Therefore, the light condensing element can reduce light loss more than the optical lens system.

  Further, in order to suppress the Fresnel loss in the optical lens system, an expensive antireflection film such as a multilayer film is necessary. On the other hand, in the reflective condensing element, there are many kinds of metals that can be used as a reflective film, and the degree of freedom in the formation of the reflective film, such as vapor deposition and sputtering, is great. And manufacturing costs can be reduced.

<Wavelength independent and compatible with wide band>
When an optical lens system is used, chromatic aberration increases as the wavelength range of light rays incident on a lens having a certain radius of curvature increases. Further, the wavelength range in which one lens medium can transmit light is limited.

  On the other hand, when a reflective condensing element such as a concave mirror is used, chromatic aberration does not occur even if the wavelength range of the light beam is widened. In addition, the wavelength range of the light beam that can be reflected can be significantly broadened compared to the lens by using a metal reflective film or the like. Therefore, the multiplexing / demultiplexing operation can be performed with the same optical system even in a wide communication wavelength range such as 0.8 to 1.55 μm.

<Channel homogeneity, incidence angle / filter pitch flexibility, multi-channel>
By optically designing the reflective condensing element arranged in the optical waveguide unit according to the arrangement interval of adjacent monochromatic light rays, that is, the arrangement interval of the light beam branching elements and the light beam incident angle to the light beam branching element, all the light beams The beam diameter of the light incident on the branch element can be made the same.

  Furthermore, the coupling efficiency in all the channels can be improved and homogenized by optically designing the light emitting / receiving point, the radius of curvature of the nearest lens, the optical path length between elements, and the like corresponding to the beam diameter. In addition, since this optical design does not depend on the number of channels, the theoretical limitation can be removed for the multi-channel optical multiplexer / demultiplexer.

  These optical designs can be implemented arbitrarily according to the incident angle of the light beam to the beam branching element and the arrangement interval of the beam branching element. Therefore, the filter characteristics can be improved by reducing the incident angle, and the flexibility of the arrangement interval of the beam branching element can be improved. It is feasible at the same time.

<Position deviation can be corrected>
In the case where there is no reflective condensing element in the optical waveguide portion, the positional deviation of the light emitting point causes an increase in the optical axis deviation of the light beam incident on the light receiving point as the optical path length increases, thereby increasing the loss. However, since the reflective condensing element is arranged on the optical path of the optical waveguide unit, the positional deviation of the light emitting point is corrected every time the propagating light beam is reflected on the reflective condensing element of the optical waveguide unit.

  Therefore, even if the optical path length is extended, the optical axis misalignment of the light incident on the light receiving point is suppressed. Can be suppressed within a practically acceptable range. Thereby, the alignment time of the light receiving and emitting points for reducing the loss can be reduced.

<Seventh Invention>
An optical multiplexer / demultiplexer according to a seventh invention is the optical multiplexer / demultiplexer according to any one of the first to fourth inventions,
An optical multiplexer / demultiplexer having two lens array blocks and arranged so that the lens array surfaces of the lens array blocks face each other.

<Eighth Invention>
An optical multiplexer / demultiplexer according to an eighth invention is the optical multiplexer / demultiplexer according to the third invention,
The holding structure for holding the beam splitter is:
A step-shaped projection structure formed on the lens array surface of the plate-shaped block body, having a rod shape having a long axis perpendicular to the lens array direction and an upper surface inclined in the lens array direction and a low step portion and a high step portion. The optical multiplexer / demultiplexer is arranged with the convex lenses interposed therebetween.

<Ninth Invention>
An optical multiplexer / demultiplexer according to a ninth invention is the optical multiplexer / demultiplexer according to the third invention,
The holding structure for holding the beam splitter is:
A step-shaped protrusion structure formed on the lens array surface of the plate-shaped block main body and including a low step portion and a high step portion along the lens array direction is formed at each end portion along the lens array direction in the block main body. It is formed with a convex lens sandwiched from all sides.
In the optical multiplexer / demultiplexer, the upper surfaces of the low and high steps are inclined in the lens array direction.

<Tenth Invention>
An optical multiplexer / demultiplexer according to a tenth aspect of the invention is the optical multiplexer / demultiplexer according to the third aspect of the invention,
The holding structure for holding the beam splitter is:
A step-shaped protrusion structure formed on the lens array surface of the plate-shaped block main body and including a low step portion and a high step portion along the lens array direction is formed at each end portion along the lens array direction in the block main body. It is formed with a convex lens sandwiched from all sides.
In the optical multiplexer / demultiplexer, the upper surfaces of the low and high step portions are inclined in the lens array direction and extend along the lens array direction.

<Eleventh invention>
An optical multiplexer / demultiplexer according to an eleventh aspect of the invention is the optical multiplexer / demultiplexer according to the third aspect of the invention,
The holding structure for holding the light beam branching element is a protruding structure having a curved surface formed at regular intervals corresponding to the convex lenses at both ends along the lens array direction of the lens array surface of the plate-like block main body. And an optical multiplexer / demultiplexer having a rod-like protrusion structure formed between the convex lenses and having a long axis perpendicular to the lens array direction.

<Twelfth Invention>
An optical multiplexer / demultiplexer according to a twelfth invention is the optical multiplexer / demultiplexer according to the third invention,
The lens array block has one or more planar grooves formed along the lens array direction in the plate-like block body, the convex lens formed on the bottom surface of the groove, and the plate-like shape. And a holding structure that protrudes from the lens array surface of the block body, has a long axis perpendicular to the lens array direction, and has an upper surface that is inclined in the lens array direction, and is arranged with the convex lenses interposed therebetween. This is an optical multiplexer / demultiplexer.

<13th invention>
An optical multiplexer / demultiplexer according to a thirteenth invention is the optical multiplexer / demultiplexer according to the second invention,
The light emitting / receiving means is an optical fiber,
In the optical multiplexer / demultiplexer, the light receiving / emitting means fixing block is formed with a linear V-shaped groove perpendicular to a surface opposite to the lens array surface for positioning and fixing the optical fiber. is there.

  As described above, according to the optical multiplexer / demultiplexer according to the present invention, (1) filter and optical fiber assembly and alignment time reduction, (2) lens member processing cost reduction, and (3) optical loss. (4) Improvement of the degree of freedom of the distance between the lens array surface and the beam splitter array surface, (5) Improvement of coupling efficiency and homogenization of variation between channels, (6) Expansion of applicable wavelength range, (7) Multi-channel optical multiplexer / demultiplexer, (8) Improvement of filter characteristics, (9) Arbitrary multiplexing / demultiplexing spectrum can be easily realized, (10) Degree of freedom of adjacent arrangement interval of optical elements of each channel (11) Improvement of positioning accuracy of the light branching element and optical fiber, (12) Improvement of focal length accuracy by the reflective condensing element, (13) Expansion of material and processing method of the reflective condensing element, 14) Reduction of parts count, (15) Environment It is possible to provide effects such as suppression of deterioration in characteristics during degrees change. As a result, it is possible to significantly reduce the loss and cost of the optical multiplexer / demultiplexer.

  Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings. However, the following embodiments do not limit the present invention.

<First Embodiment>
FIG. 1 is a schematic configuration diagram of an optical multiplexer / demultiplexer according to the first embodiment of the present invention. In the figure, light rays propagating through the optical multiplexer / demultiplexer are conceptually shown.

  As shown in FIG. 1, the optical multiplexer / demultiplexer according to the first embodiment transmits a light beam including a specific wavelength range and a lens 20 for inputting / outputting wavelength-multiplexed light rays and other than the specific wavelength range. The light splitting elements 11 to 14 that reflect the light, the reflecting surfaces 21 to 23 that reflect the light, and the first lens array block 10 are configured. In addition, optical fibers 15 to 19 are coupled to the optical multiplexer / demultiplexer so that wavelength multiplexed light or monochromatic light can be input and output.

  The first lens array block 10 includes lenses 1 to 4 for inputting / outputting monochromatic light beams, and light beam branching element holding structures 5 to 9 protruding from the lens array block main body and holding the light beam branching elements 11 to 14. In the first lens array block 10, the lenses 1 to 4 and the beam branching element holding structures 11 to 14 are alternately arranged. That is, for example, the lens 1 is disposed between the protruding beam branching element holding structure 5 and the beam branching element holding structure 6, and the other lenses 2 to 4 have two protruding beam branching element holding structures, respectively. Arranged between.

  Further, for example, the light beam branching element 11 is held at both ends on the upper surfaces of the protruding light beam branching element holding structure 5 and the light beam branching element holding structure 6, and the other light beam branching elements 12 to 14 are also 2 respectively. Two projecting beam branching element holding structures hold both ends thereof. As a result, the lenses 1 to 4 and the beam splitters 11 to 14 corresponding to them are arranged in pairs (four pairs in FIG. 1) and arranged in the lens array block body. The lenses 1 to 4 are lenses that are convex toward the beam splitters 11 to 14.

  The optical fiber 15, the lens 20, and the reflecting surfaces 21 to 23 are on the side of the beam splitters 11 to 14 held by the first lens array block 10, and the optical fibers 16 to 19 are held by the beam splitters 11 to 14. It is installed on the opposite side to the side where it was done.

  When the optical multiplexer / demultiplexer according to this embodiment is used as a demultiplexer, the operation principle of the demultiplexer is as follows. The wavelength multiplexed light propagating through the optical fiber 15 from the outside of the optical multiplexer / demultiplexer is guided into the optical multiplexer / demultiplexer and enters the lens 20 as a slightly diffused wavelength multiplexed light. The wavelength multiplexed light is collimated by the lens 20 and then enters the light beam splitting element 11.

  The wavelength-multiplexed light incident on the light beam splitting element 11 is transmitted through the light beam splitting element 11 with a light having a specific wavelength range, becomes a monochromatic light beam, enters the lens 1, is condensed on the lens 1, and is coupled to the optical fiber 16. And output to the outside of the optical multiplexer / demultiplexer.

  A wavelength-multiplexed light beam composed of light beams outside the specific wavelength range is reflected without being transmitted by the light beam splitting element 11 and propagated to the reflection surface 21. The wavelength multiplexed light propagated to the reflecting surface 21 is reflected by the reflecting surface 21 and enters the light beam splitting element 12.

  The wavelength-multiplexed light incident on the light beam splitting element 12 is transmitted through the light beam splitting element 12 with a light having a specific wavelength range, becomes a monochromatic light beam, enters the lens 2, is condensed on the lens 2, and is coupled to the optical fiber 17. And output to the outside of the optical multiplexer / demultiplexer.

  By repeating the above process, the wavelength multiplexed light incident from the optical fiber 15 can be extracted from the optical fibers 16 to 19 as a plurality of demultiplexed monochromatic light beams.

  Further, when the optical multiplexer / demultiplexer according to the present embodiment is used as a multiplexer, it corresponds to a case where the traveling directions of the wavelength multiplexed light and the monochromatic light in the demultiplexing operation described above are reversed. That is, by inputting monochromatic rays to the optical fibers 16 to 19 from the outside of the optical multiplexer / demultiplexer, the plurality of monochromatic rays can be extracted from the optical fiber 15 as a multiplexed wavelength multiplexed ray.

  About the optical path of the light beam propagating between the reflecting surfaces 21 to 23 and the light beam branching elements 11 to 14, the optical path length between the reflecting surface and the light beam branching device, the interval between the adjacent light beam branching devices, It can be uniquely determined by fixing two of the three elements of the light incident angle. Therefore, in general, it is desirable to shorten the optical path length and reduce the light incident angle to the light branching element. However, these designs are limited by the size of the light branching elements 11 to 14 and the lenses 1 to 4. Is done.

  Each of the optical fibers 16 to 19 of each channel passes through a straight line connecting end faces of the adjacent optical fibers (surfaces formed by cutting perpendicularly to the optical fiber axis, the same shall apply hereinafter) and end faces of the respective optical fibers. The optical axes of the light beams are arranged so as to be orthogonal to each other, and the optical path lengths between the lenses 1 to 4 and the end faces of the corresponding optical fibers 16 to 19 are the same in each channel.

  Therefore, the collimated light beam can be obtained so that the highest possible coupling efficiency can be obtained regardless of whether the optical fiber 16 has the shortest optical path length or the optical fiber 19 has the longest optical path length. It is necessary to optically design the diameter.

  Convergent light (in the case of a demultiplexer) or diffused light (in the case of a multiplexer) propagates between the end faces of the optical fibers 16 to 19 and the lenses 1 to 4, so that the beam as designed is propagated. In order to achieve this, it is necessary to precisely determine the relative position and angle between the optical fiber and the lens. Therefore, it is desirable to form a structure for simply and accurately fixing the optical fibers 16 to 19 in the lens array block 10 (described in detail in FIG. 12).

  In the present embodiment, the optical fibers 16 to 19 for inputting / outputting monochromatic light, the lenses 1 to 4, and the light branching elements 11 to 14 are arranged on one straight line. Can be collectively arranged in an array, and each optical element can be easily arranged, formed and fixed.

  In the present embodiment, the number of beam branching elements is four, the number of lenses is five, the number of reflecting surfaces is three, and the number of optical fibers is five. However, the present invention is limited to these numbers. It is not limited. The light receiving and emitting points for wavelength multiplexed light and monochromatic light are not limited to optical fibers, and some or all of the light receiving and emitting points may be light receiving and emitting elements such as laser diodes and photodiodes. Furthermore, a configuration may be adopted in which a plurality of light emitting points and light receiving points exist in one optical multiplexer / demultiplexer.

  FIG. 2 is a schematic configuration diagram of the optical multiplexer / demultiplexer according to the first embodiment, and shows an example in which two lens array blocks having the same shape are used. In the figure, light rays propagating through the optical multiplexer / demultiplexer are conceptually shown. As shown in FIG. 2, the first lens array block 10 and the second lens array block 27 are manufactured by injection molding using the same mold and have the same shape.

  The first lens array block 10 holds the beam splitters 11 to 14 in its holding structure, and the second lens array block 27 holds the reflecting surfaces 21 to 23 in its holding structure. The blocks 10 and 27 are arranged so that the surfaces holding the light beam splitting elements or the reflecting surfaces are opposed to each other, and further, the relative positions of the blocks 10 and 27 are adjusted so that the blocks made of members of the same shape can be obtained. An optical multiplexer / demultiplexer can be configured by using it.

  By optimizing the optical design of the lens, the second lens array block 27 can use a member having the same shape as that of the first lens array block 10, and the reflecting surfaces 21 to 23 are arranged in place of the beam splitter. Thus, an optical multiplexer / demultiplexer can be configured by making them face each other. Accordingly, positioning of the reflecting surface can be performed accurately and easily, so that the assembly time can be shortened. Here, the reason for optimizing the optical design of the lens is, for example, that the lens 20 shown in FIG. 1 does not need to be a lens having the same radius of curvature as the lens 4, but the lens 20 shown in FIG. 2 is the same as the lens 4. This is because the blocks 10 and 27 cannot be formed into the same shape member unless the radius of curvature is set to, and optimization is required under such restrictions.

  Further, in the optical multiplexer / demultiplexer shown in FIG. 2, not only the beam splitters 11 to 14 but also the reflecting surfaces 21 to 23 can be positioned accurately and easily, so that the assembly time can be further reduced. Further, by molding the blocks 10 and 27 as a single unit, after molding as a united block, it is not necessary to adjust the relative positions of the blocks, and the assembly time can be further reduced.

<Second Embodiment>
FIG. 3 is a schematic configuration diagram of an optical multiplexer / demultiplexer according to the second embodiment of the present invention, which is an application example of the first embodiment. In the figure, light rays propagating through the optical multiplexer / demultiplexer are conceptually shown.

  As shown in FIG. 3, in the second embodiment, concave mirrors 24 to 26 that are reflective condensing elements are used instead of the reflective surfaces 21 to 23 in the first embodiment. Other members are the same as those in the first embodiment.

  In order to increase the number of channels of the optical multiplexer / demultiplexer, it is necessary to increase the optical path length between adjacent beam splitters. In addition, when the pitch between adjacent channels cannot be reduced, the optical path length between adjacent beam splitters is increased in order to reduce the beam incident angle to the beam splitter for the purpose of improving the filter characteristics. There is a need. However, as the optical path length increases, the light beam diffuses and the loss increases.

  On the other hand, in the second embodiment, by applying the concave mirrors 24 to 26 and optimizing the curvature radius of the mirror, the beam diameters of the light beams incident on the light beam branching elements 11 to 14 are made uniform. It is possible to suppress an increase in loss.

  FIG. 4 is a schematic configuration diagram of the optical multiplexer / demultiplexer according to the second embodiment, and shows an example in which a reflection condensing element array block is formed by integrating a plurality of concave mirrors. In the figure, light rays propagating through the optical multiplexer / demultiplexer are conceptually shown.

  In the reflective condensing element array block 55, concave mirrors 24 to 26 and lenses 20 for inputting / outputting wavelength-multiplexed rays are arranged in a line and integrally formed. Therefore, by adjusting the relative position of the reflective condensing element array block 55 with respect to the first lens array block 10, the positions of the concave mirrors 24 to 26 and the lens 20 can be accurately determined collectively, so that the assembly time can be reduced. The number of parts can be reduced.

  Further, by molding the blocks 10 and 55 as a single unit, it is not necessary to adjust the relative positions of the blocks after molding as a united block, and the assembly time can be further reduced.

<Third Embodiment>
FIG. 5 is a schematic configuration diagram of an optical multiplexer / demultiplexer according to the third embodiment of the present invention, which is an application example of the first embodiment. In the figure, light rays propagating through the optical multiplexer / demultiplexer are conceptually shown.

  As shown in FIG. 5, in 3rd Embodiment, the reflective surface 28 which integrated these reflective surfaces into one sheet is used instead of the reflective surfaces 21-23 in 1st Embodiment. In the first lens array block 10, lenses 20 for inputting / outputting wavelength-multiplexed rays are formed in a line along with the lenses 1-4.

  The beam splitters 11 to 14 have the beam splitter / element holding structures 5 to 9 such that the light incident / reflecting surfaces thereof are parallel to the surfaces of the first lens array block 10 in which the lenses 1 to 4 and 20 are aligned. Retained. Further, the integrated reflecting surface 28 is a light incident / reflecting surface of the light branching elements 11 to 14 on the side of the light branching elements 11 to 14 held by the first lens array block 10. It is installed so as to be parallel to.

  The optical fiber 15 for inputting / outputting wavelength-multiplexed rays is installed on the opposite side of the reflecting surface 28 with the first lens array block 10 interposed between the optical fibers 16 to 19 for inputting / outputting monochromatic rays.

  A line connecting light receiving and emitting points (points for receiving and emitting light rays at the end face) in each of the optical fibers 15 to 19 is parallel to the filter array surface and the reflecting surfaces of the light beam splitting elements 11 to 14, while the optical fibers 15 to 15 are connected. The light emitting / receiving surface (end surface) of 19 is not parallel. That is, the optical fibers 15 to 19 are arranged so that their light receiving and emitting surfaces are inclined with respect to the filter array surface.

  Since the beam splitters 11 to 14 are parallel (not inclined) to the lens array surface or the filter array surface, a single flat plate 28 can be used as the reflecting surface.

  In the optical multiplexer / demultiplexer according to the present embodiment, since all the optical fibers 15 to 19 are arranged on one surface of the optical multiplexer / demultiplexer, it is suitable for mounting the optical multiplexer / demultiplexer on the corner of the package or the like. Yes.

<Fourth Embodiment>
FIG. 6 is a schematic configuration diagram of an optical multiplexer / demultiplexer according to the fourth embodiment of the present invention, which is an application example of the third embodiment. In the figure, light rays propagating through the optical multiplexer / demultiplexer are conceptually shown.

  As shown in FIG. 6, the optical multiplexer / demultiplexer according to the fourth embodiment has substantially the same configuration as the block 10 instead of the reflecting surface 28 in the third embodiment, together with the first lens array block 10. The second lens array block 27 is used. Furthermore, the optical fibers 33 to 36 are also coupled to the block 27 side.

  The second lens array block 27 includes lenses 61 to 64 that input and output a monochromatic light beam, and light beam branching elements 29 to 32 that are held in a protruding light beam branching element holding structure. Although the lens 20 is not provided in the second lens array block 27, this is because wavelength multiplexed light is input / output from the block 10 side in this embodiment. In order to manufacture the block 27 with the same mold as that of the block 10, the lens 20 may be provided in the block 27. In this case, the lens 20 provided in the block 27 may not be used, or the lens may be used by inputting / outputting wavelength multiplexed light from the block 27 side.

  As in the optical multiplexer / demultiplexer according to the present embodiment, instead of the reflecting surface 28, a lens array block 27 configured to hold the light beam splitting elements 29 to 32 and the lenses 61 to 64 is installed, and further the light. By arranging the fibers 33 to 36, the number of channels of the optical multiplexer / demultiplexer can be doubled.

<Fifth Embodiment>
FIG. 7 is a schematic perspective view of a lens array block of an optical multiplexer / demultiplexer according to the fifth embodiment of the present invention, which can be applied as the lens array block in the first and second embodiments.

  As shown in FIG. 7, the lens array block 10 of the optical multiplexer / demultiplexer according to the fifth embodiment includes a plate-like block main body 56 and protruding light rays formed on one side of the block main body 56 at a constant interval. It consists of the branching element holding structures 5 to 9 and convex lenses 1 to 4 provided between the adjacent beam branching element holding structures with a certain interval.

  The beam splitter holding structures 5 to 9 each have a rod-like and two-step staircase shape having a long axis perpendicular to the lens array direction, and the staircase shape is a terrace surface 6a to 9a having a low step (low step portion). It consists of terrace surfaces 5b-9b of high tiers (high tiers). Further, the beam branching element holding structures 5 to 9 are formed so that the lower terrace surfaces and the higher terrace surfaces are alternately arranged along the lens array direction.

  Each beam branching element is installed with its both ends held on the adjacent high terrace surface and the lower terrace surface so as to cover each lens 1 to 4. That is, both ends of each beam branching element are held by the high terrace surface 5b and the low terrace surface 6a, similarly the terrace surfaces 6b and 7a, the terrace surfaces 7b and 8a, and the terrace surfaces 8b and 9a.

  In this way, since the light beam branching elements are installed across the high level terrace surface and the low level terrace surface that are installed with a certain interval, each light beam splitting element is connected to the plate-shaped block body 56. Will be installed at an angle. Each terrace surface is an inclined surface having the same angle as the inclination angle of the light beam branching element in order to hold the light beam branching element with the surface. Thus, in this embodiment, the position and angle of each beam splitter are determined and fixed by each terrace surface.

  The beam splitter holding structure 5 does not have a lower terrace surface. Further, the light beam branching element is not held on the terrace surface 9 b of the higher stage of the light beam branching element holding structure 9.

  In this embodiment, since each light branching element holding structure is formed between adjacent lenses, it is sufficient to prepare a light branching element that is slightly larger than the lens diameter. Therefore, the area of the beam splitter can be reduced, and the manufacturing cost can be reduced.

<Sixth Embodiment>
FIG. 8 is a schematic perspective view of a lens array block of an optical multiplexer / demultiplexer according to the sixth embodiment of the present invention, which is an application example of the fifth embodiment. Further, it can be applied as a lens array block in the first and second embodiments.

  As shown in FIG. 8, the lens array block 10 according to the sixth embodiment has a rod-shaped beam branching element holding structure in the fifth embodiment in which the rod-shaped central portion is eliminated. In other words, the light-branching element holding structure 5 is located on a vertical bisector (not limited to a bisector) perpendicular to a line connecting the lens top surfaces of adjacent lenses and located at both ends of the block body 56. Two to 9 are formed.

  It is assumed that the light branching element holding structures 5 and 9 are formed on the opposite side of the lens 2 with the lens 1 in between, or on the opposite side of the lens 3 with the lens 4 in between. And follow the above description. The shape of the light beam branching element holding structures 5 to 9 is the same as that described in the fifth embodiment, such as a two-step staircase shape and a low and high stepped terrace surface.

  In the lens array block according to the sixth embodiment, the light beam branching element holding structures 5 to 9 do not exist as a barrier between adjacent lenses, and the adjacent light beam branching element holding structures have a predetermined interval. Thus, the effective area of the lenses 1 to 4 can be increased, or the arrangement interval between adjacent lenses can be reduced.

<Seventh Embodiment>
FIG. 9 is a schematic perspective view of a lens array block of an optical multiplexer / demultiplexer according to the seventh embodiment of the present invention, which is an application example of the sixth embodiment. Further, it can be applied as a lens array block in the first and second embodiments.

  As illustrated in FIG. 9, the lens array block 10 according to the seventh embodiment includes terrace surfaces 6 a to 9 a and 5 b to constitute the light beam branching element holding structures in the light beam branching element holding structure in the sixth embodiment. The shape 9b is elongated in the lens array direction. The shape of the light beam branching element holding structures 5 to 9 is the same as that described in the fifth embodiment, such as a two-step staircase shape and a low and high stepped terrace surface.

  In the lens array block according to the seventh embodiment, since the beam branching element holding structures 5 to 9 do not exist as a barrier between adjacent lenses, the effective area of the lenses 1 to 4 is increased, or the adjacent lens The arrangement interval can be narrowed. Further, when the lens array block 10 is manufactured by injection molding using a mold, since the areas of the terrace surfaces 6a to 9a and 5b to 9b are increased, the beam branching element holding structures 5 to 9 are easily formed. be able to.

<Eighth Embodiment>
FIG. 10 is a schematic perspective view of the lens array block of the optical multiplexer / demultiplexer according to the eighth embodiment of the present invention, which can be applied as the lens array block in the first and second embodiments.

  As shown in FIG. 10, the lens array block 10 of the optical multiplexer / demultiplexer according to the eighth embodiment includes a plate-like block main body 56 and a convex lens 1 formed on one side of the block main body 56 with a constant interval. 4 and protrusion-shaped light beam splitting element anti-slip structures 41 to 44 provided between adjacent lenses, and bumps formed at regular intervals corresponding to the light beam branching element anti-slip structures 41 to 44, respectively. It consists of the light-branching-element holding structures 37-40 of a shape (1/4 spherical shape). The bump shape may be, for example, a half spherical shape, and may be a structure having a curved shape.

  Each of the protruding beam branching element anti-slip structures 41 to 44 has a rod-like shape having a long axis perpendicular to the lens array direction. Further, the beam branching element holding structures 37 to 40 are on a vertical bisector (not limited to a bisector) perpendicular to a line connecting the lens top surfaces of adjacent lenses, and at both ends of the block main body 56. Two are formed at each position.

  The formation position of the light beam splitting element anti-slip structure 44 is as described above on the assumption that the lens is located on the opposite side of the lens 3 with the lens 4 in between. Further, the formation position of the beam branching element holding structure 37 is based on the above description on the assumption that the lens is located on the opposite side of the lens 2 with the lens 1 in between.

  FIG. 10 shows that a unit (for example, the lens 1, the anti-slip structure 41, and the holding structure 37) composed of a lens, a light-branching element anti-slip structure, and a light-branching element holding structure is divided into four units on the block body 56. It has a formed structure.

  Each light beam branching element is installed with its both ends held by the corresponding light beam branching element anti-slip structure and the light beam branching element holding structure so as to cover each lens 1 to 4. That is, both ends of each beam splitter are held by the anti-slip structure 41 and the holding structure 37, similarly by the structures 42 and 38, the structures 43 and 39, and the structures 44 and 40.

  One end of the beam branch element is supported at two points substantially on the top surface of the beam branch element holding structure (for example, 37) formed as a pair, and the other end is a corresponding beam branch element anti-slip structure (for example, 41). The surface of the block body 56 between the lens and the lens (for example, 1) is in contact with the line and supported by the corresponding beam branching element non-slip structure (for example, 41) so as not to slide toward the adjacent lens (for example, 2). Yes.

  In this way, since the light beam branching element is installed across the light beam branching element holding structure and the light beam splitting element anti-slip structure that are installed with a fixed interval, each light beam branching element is attached to the plate-like block main body 56. It will be installed with an inclination. In the present embodiment, the position and the inclination angle of the light beam branching element are adjusted according to the radius of the bump-shaped light beam branching element holding structure and the distance between the holding structure and the light beam splitting element anti-slip structure.

  In this embodiment, since the beam branching element holding structures 37 to 40 are formed in a bump shape, it is easier to form than the step-shaped structure, and the manufacturing cost of the lens array block can be reduced. Furthermore, since the inclination angle of the beam branching element can be adjusted and determined by the radius of the bump, the accuracy of the inclination angle can be improved.

<Ninth Embodiment>
FIG. 11 is a schematic perspective view of a lens array block of an optical multiplexer / demultiplexer according to the ninth embodiment of the present invention, which can be applied as the lens array block in the first and second embodiments.

  As shown in FIG. 11, the lens array block 10 of the optical multiplexer / demultiplexer according to the ninth embodiment includes a plate-like block main body 56 and protruding light beams formed on one side of the block main body 56 with a constant interval. Formed on the bottom surfaces of the branch element holding structures 5 to 9 and the shallow groove structures 51 to 54 provided between the beam branching element holding structures adjacent to each other with a certain interval. Consists of convex lenses 1-4.

  The groove structures 51 to 54 are substantially square in plan shape, and the depth is such that the top surface of the convex lenses 1 to 4 formed on the bottom surface of the groove does not protrude higher than the surface of the block body 56. ing. Further, each of the projecting beam branching element holding structures 5 to 9 has a rod shape having a long axis perpendicular to the lens array direction, and the upper surface thereof is a surface inclined in the lens array direction.

  Each light beam branching element is installed with its both ends held by adjacent light beam branching element holding structures so as to cover each lens 1 to 4 formed in the groove structures 51 to 54. That is, both ends of each beam branching element are held by the beam branching element holding structures 5 and 6, similarly the structures 6 and 7, the structures 7 and 8, and the structures 8 and 9.

  One end of the beam branch element is supported by a surface on the upper surface of the beam branch element holding structure (for example, 5), and the other end is a lens (for example, 1) covered by the beam branch element in the adjacent beam branch element holding structure (for example, 6). ) Side surface and the surface of the block main body 10 by a line, and supported by an adjacent beam branching element holding structure (for example, 6) so as not to slide toward the adjacent lens (for example, 2). The light beam branching element is not held on the upper surface of the light beam branching element holding structure 9.

  In this way, each beam branching element is installed across the upper surface of the beam branching element holding structure and the side surface (and the surface of the block body) of the holding structure adjacent to the beam branching element holding structure. It will be installed at an angle. Further, the upper surface of each beam branching element holding structure is an inclined surface having the same angle as the tilt angle of the beam branching element in order to hold the beam branching element with the surface.

  In this embodiment, since each light branching element holding structure is formed between adjacent lenses, it is sufficient to prepare a light branching element that is slightly larger than the lens diameter. Therefore, the area of the beam splitter can be reduced, and the manufacturing cost can be reduced. Furthermore, since the lens formed inside the groove structure and the light beam branching element do not interfere with each other, the inclination angle of the light beam branching element can be reduced.

<Tenth Embodiment>
FIG. 12 is a perspective schematic external view of a lens array block of an optical multiplexer / demultiplexer according to the tenth embodiment of the present invention, which can be applied as the lens array block in the first and second embodiments.

  As shown in FIG. 12, the lens array block 49 of the optical multiplexer / demultiplexer according to the tenth embodiment includes a portion of the lens array block 10 (see FIG. 8) described in the sixth embodiment and an optical fiber. It consists of the part of the block 57 to fix. These two blocks 10 and 57 are integrally formed such that the block 57 for fixing the optical fiber is positioned on the back side of the surface of the lens array block 10 on which the lenses 1 to 4 are formed.

  The block 57 for fixing the optical fiber has V grooves 45 to 48 for fixing the optical fiber on the surface thereof. The V grooves 45 to 48 are formed on the lenses 1 to 4 formed in the lens array block 10. It is linearly formed.

  According to the lens array block 49 according to the present embodiment, the relative positions and angles of the light beam splitting elements, the lenses 1 to 4 and the optical fiber (light emitting / receiving point) can be determined and fixed in a lump. It is possible to greatly reduce the assembly time of the duplexer.

  The V grooves 45 to 48 are formed most easily when the linear axis is formed so as to be perpendicular to the lens array surface (perpendicular to the main body surface of the block 10). However, it may be formed obliquely with respect to the lens array surface according to circumstances, and may be formed so that the inclination angle becomes a plurality of angles.

  Further, by forming the V grooves 45 to 48 relatively deeply, not only the optical fiber but also the transmitting or receiving optical subassembly mounted on the cylindrical housing can be easily positioned and fixed accurately. it can. The groove shape is not limited to the V-groove, and may be a U-groove or a concave groove.

  As described above, as a method for forming the lens, the beam branching element holding structure, the V-groove, and the like described in each embodiment, a cutting process in which a substrate is directly cut into a target shape or a mold having a target shape is cut. An injection molding method in which a resin or the like is poured into the mold and heated and molded can be considered. However, when a large number of the same lens array block is manufactured, an injection molding method is suitable.

  The present invention has been described with reference to the case where the present invention is applied to an optical multiplexer / demultiplexer. However, the present invention uses a beam splitter having a function of transmitting a specific amount of light among incident rays and reflecting the remaining amount of light. Even when the present invention is applied to such a device, that is, an optical coupler or an optical distributor, it is possible to provide substantially the same effect as that of the optical multiplexer / demultiplexer.

It is a schematic block diagram of the optical multiplexer / demultiplexer which concerns on 1st Embodiment. It is a schematic block diagram of the optical multiplexer / demultiplexer which concerns on 1st Embodiment, and is the example comprised using two lens array blocks of the same shape. It is a schematic block diagram of the optical multiplexer / demultiplexer which concerns on 2nd Embodiment, and is an application example of 1st Embodiment. It is a schematic block diagram of the optical multiplexer / demultiplexer which concerns on 2nd Embodiment, and is the example comprised using the reflective condensing element array block which integrates a some concave mirror. It is a schematic block diagram of the optical multiplexer / demultiplexer which concerns on 3rd Embodiment, and is an application example of 1st Embodiment. It is a schematic block diagram of the optical multiplexer / demultiplexer which concerns on 4th Embodiment, and is an application example of 3rd Embodiment. FIG. 10 is a schematic perspective view of a lens array block of an optical multiplexer / demultiplexer according to a fifth embodiment. It is a perspective schematic structure figure of the lens array block of the optical multiplexer / demultiplexer which concerns on 6th Embodiment. It is a perspective schematic structure figure of the lens array block of the optical multiplexer / demultiplexer which concerns on 7th Embodiment. It is a schematic perspective view of the lens array block of the optical multiplexer / demultiplexer according to the eighth embodiment. It is a schematic perspective view of the lens array block of the optical multiplexer / demultiplexer according to the ninth embodiment. It is a perspective schematic external view of the lens array block of the optical multiplexer / demultiplexer which concerns on 10th Embodiment. It is a schematic block diagram of an example of the conventional optical multiplexer / demultiplexer.

Explanation of symbols

1-4 Lens for inputting / outputting monochromatic light 5-9 Beam branching element holding structure 6a-9a Lower terrace surface 5b-9b High terrace surface 10 First lens array block 11-14 Beam branching element 15 -19 Optical fiber 20 Lens for inputting / outputting wavelength multiplexed light 21-23 Reflecting surface 24-26 Concave mirror as reflection condensing element 27 Second lens array block 28 Reflecting surface 29-32 Beam splitter 33-36 Optical fiber 37 to 40 Bump-shaped light branching element holding structure 41 to 44 Light branching element anti-slip structure 45 to 48 V groove for fixing an optical fiber 49 Lens array block 51 to 54 in which an optical fiber fixing block is integrated Structure 55 Reflective condensing element array block 56 Block body 57 Block for fixing optical fiber 61-64 single Lens for inputting and outputting light rays

Claims (13)

A plate-shaped block body;
One or more convex lenses formed on one surface of the block body;
A holding structure that is formed on the block main body and that determines the position and angle of one or a plurality of light branching elements on the optical path of the light passing through each convex lens and on the same surface side as the one-side surface is integrally formed. An optical multiplexer / demultiplexer comprising a lens array block. In the optical multiplexer / demultiplexer according to claim 1,
Further, the light receiving / emitting means fixing block for positioning the light receiving / emitting means for delivering the light to and from the optical multiplexer / demultiplexer is integrally formed on the surface of the lens array block opposite to the lens array surface. Optical multiplexer / demultiplexer. The optical multiplexer / demultiplexer according to claim 1 or 2,
An optical multiplexer / demultiplexer characterized in that the light beam splitting element is held such that a light incident / reflecting surface is inclined with respect to the lens array surface. The optical multiplexer / demultiplexer according to claim 1 or 2,
The optical beam splitter is characterized in that the light incident / reflecting surface is held parallel to the lens array surface. The optical multiplexer / demultiplexer according to any one of claims 1 to 4,
An optical multiplexer / demultiplexer, wherein one or a plurality of reflection condensing elements are arranged on an optical path until a reflected light beam from a light beam splitting element enters another light beam splitting device. The optical multiplexer / demultiplexer according to claim 5,
The optical multiplexer / demultiplexer, wherein the one or a plurality of reflection condensing elements are integrally formed as a reflection condensing element array block facing the lens array block. The optical multiplexer / demultiplexer according to any one of claims 1 to 4,
2. An optical multiplexer / demultiplexer comprising two lens array blocks, the lens array surfaces of the lens array blocks being opposed to each other. In the optical multiplexer / demultiplexer according to claim 3,
The holding structure for holding the beam splitter is:
A step-shaped projection structure formed on the lens array surface of the plate-shaped block body, having a rod shape having a long axis perpendicular to the lens array direction and an upper surface inclined in the lens array direction and a low step portion and a high step portion. An optical multiplexer / demultiplexer arranged with the convex lenses interposed therebetween. In the optical multiplexer / demultiplexer according to claim 3,
The holding structure for holding the beam splitter is:
A step-shaped protrusion structure formed on the lens array surface of the plate-shaped block main body and including a low step portion and a high step portion along the lens array direction is formed at each end portion along the lens array direction in the block main body. It is formed with a convex lens sandwiched from all sides.
The optical multiplexer / demultiplexer according to claim 1, wherein upper surfaces of the low step portion and the high step portion are inclined in a lens array direction. In the optical multiplexer / demultiplexer according to claim 3,
The holding structure for holding the beam splitter is:
A step-shaped protrusion structure formed on the lens array surface of the plate-shaped block main body and including a low step portion and a high step portion along the lens array direction is formed at each end portion along the lens array direction in the block main body. It is formed with a convex lens sandwiched from all sides.
The optical multiplexer / demultiplexer according to claim 1, wherein upper surfaces of the low step portion and the high step portion are inclined in the lens array direction and extend along the lens array direction. In the optical multiplexer / demultiplexer according to claim 3,
The holding structure for holding the beam splitter is:
It is a curved projection structure formed at regular intervals corresponding to each convex lens at both ends along the lens array direction on the lens array surface of the plate-shaped block body, and further, between the convex lenses. And an optical multiplexer / demultiplexer having a rod-like protrusion structure having a long axis perpendicular to the lens array direction. In the optical multiplexer / demultiplexer according to claim 3,
The lens array block has one or more planar grooves formed along the lens array direction in the plate-like block body, the convex lens formed on the bottom surface of the groove, and the plate-like shape. And a holding structure that protrudes from the lens array surface of the block body, has a long axis perpendicular to the lens array direction, and has an upper surface that is inclined in the lens array direction, and is arranged with the convex lenses interposed therebetween. An optical multiplexer / demultiplexer characterized by that. The optical multiplexer / demultiplexer according to claim 2,
The light emitting / receiving means is an optical fiber,
An optical multiplexer / demultiplexer characterized in that a linear V-shaped groove perpendicular to the surface opposite to the lens array surface for positioning and fixing the optical fiber is formed in the light receiving / emitting means fixing block.

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