JP2010282142A - Demultiplexer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a demultiplexer in which the wavelength multiplexed light is demultiplexed by a simple structure and a light quantity loss is reduced when the wavelength multiplexed light is demultiplexed. <P>SOLUTION: The demultiplexer 100 includes: a lens 70 for collecting the wavelength multiplexed light emitted from an optical fiber 80; a substrate 50 having four photodetectors 1-4 arranged respectively in four areas like a two-row, two-column matrix; two optical members 30, 40 which constitute a first layer of the substrate and are arranged side by side in the Y-axis direction; and two optical members 10, 20 which constitute a second layer of the substrate and are arranged side by side in the X-axis direction. The four optical members have wavelength selecting films 12-42 different in wavelength selecting property on the front surface sides, respectively. The demultiplexer divides the wavelength multiplexed light into four demultiplexed lights by two superposed layers of the wavelength selecting films by wavelength and makes the four demultiplexed lights incident on the photodetectors, respectively. The structure of the demultiplexer is made simple and the light quantity loss from the optical fiber to the photodetectors is decreased to around -6 dB of a quarter of a numerical aperture. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a duplexer, and more particularly to a duplexer used for wavelength division multiplexing communication.

  In recent years, in the field of optical communication, the use of a wavelength-division-multiplexing (WDM) method that multiplexes and transmits a number of different wavelengths of light on a single optical fiber is increasing. Various methods such as a method using a diffraction grating, a method using a dielectric multilayer filter having wavelength selectivity, and a method using an optical waveguide have been proposed for demultiplexing wavelength multiplexed light.

  Patent Document 1 below describes a duplexer (1) using a diffraction grating. The duplexer (1) includes an optical fiber (41) on the host side, three optical fibers (51), (52) and (53) on the terminal side, and a diffraction grating (12) on the surface on the host side. And a pair of collimator lenses (20) and (21) arranged so as to sandwich the diffraction grating member (10).

  Wavelength multiplexed light (1.31 μm, 1.55 μm) emitted from the optical fiber (41) on the host side passes through the collimator lens (20) and is demultiplexed for each wavelength by the diffraction grating (12). The demultiplexed light is converted into parallel light by the collimator lens (21) and input to the optical fibers (51) and (53).

JP 2002-341176 A (paragraphs [0019], [0020] FIG. 1)

  In the case of demultiplexing by a diffraction grating as described in Patent Document 1 above, when the light source on the transmission side is a single mode laser and the optical fiber is also a single mode fiber, the polarization plane of the received light is guaranteed. Therefore, the demultiplexing by the diffraction grating functions effectively.

On the other hand, when the light source on the transmission side is a multi-mode laser and the optical fiber is also a multi-mode fiber, the polarization plane of the received light collapses and is not guaranteed. The diffraction grating does not function effectively with respect to the incoherent wavefront, and problems such as insufficient diffraction angle occur.
Therefore, for example, a method of supplementing the demultiplexing by the diffraction grating by adding a dielectric multilayer film or the like can be considered.

  However, in this case, the structure becomes complicated, so that the mounting is difficult and the cost is increased. In this case, there also arises a problem that the light loss due to demultiplexing is large. In particular, the light loss is about −3 dB to −6 dB for the diffraction grating and about −3 dB to −6 dB for the dielectric multilayer film, so that the total loss reaches about −6 dB to −12 dB.

  In view of the circumstances as described above, an object of the present invention is to provide a duplexer capable of demultiplexing wavelength multiplexed light with a simple structure and capable of reducing light loss during demultiplexing. There is.

In order to achieve the above object, a duplexer according to an aspect of the present invention includes a substrate, a first layer, a second layer, first and second optical members, third and fourth components. And an optical member.
The substrate includes first to fourth regions and first to fourth light receiving elements.
The first to fourth regions are divided by a first boundary line and a second boundary line orthogonal to the first boundary line.
The first to fourth light receiving elements are provided in the respective regions.
The first layer is stacked on the substrate.
The second layer is stacked on the first layer.
Each of the first and second optical members constitutes a part of the second layer.
The first and second optical members each have a wavelength selection unit, and are respectively disposed corresponding to two regions adjacent in the direction along the first boundary line among the regions.
The wavelength selectors of the first and second optical members selectively transmit light in different wavelength regions from the light emitted from the optical fiber.
The third and fourth optical members each constitute a part of the first layer.
The third and fourth optical members each have a first wavelength selection unit, and are respectively disposed corresponding to two regions adjacent to each other in the direction along the second boundary line among the regions. The
The first wavelength selectors of the third and fourth optical members selectively transmit light in different wavelength regions among the light that has passed through the first and second optical members.

  In the present invention, the wavelength multiplexed light emitted from the optical fiber can be demultiplexed into four for each wavelength by the arrangement and wavelength selection characteristics of each optical member as described above. That is, the wavelength multiplexed light can be demultiplexed into four by the principle of superposition of wavelength selection characteristics. Thereby, the demultiplexed light demultiplexed for each wavelength can be made incident on each light receiving element arranged in a matrix.

  In the present invention, the optical members having the same configuration are laminated in two layers on the substrate, so that a duplexer capable of quadrant separation can be formed. Thus, in the present invention, the structure is extremely simple. As a result, the mounting is simplified and the cost can be reduced.

  Furthermore, in the present invention, the light amount loss from the optical fiber to each light receiving element is about −6 dB for the four divided openings of the wavelength multiplexed light, and the light amount loss can be reduced.

In the duplexer, each of the first and second optical members may further include a reflecting portion in a portion close to each other.
In this case, each of the third and fourth optical members may further include a reflecting portion in a portion close to each other.

  When demultiplexed light demultiplexed for each wavelength is incident on each light receiving element, crosstalk occurs between the respective light receiving elements due to incident light on the substrate between the light receiving elements. There is a case.

  In the present invention, the two optical members constituting the first layer each have a reflecting portion in the adjacent portion, and the two optical members constituting the second layer also have the reflecting portion in the adjacent portion. is doing. Thereby, crosstalk between the light receiving elements can be prevented.

In the duplexer, the reflecting portions of the first and second optical members may be inclined at a predetermined angle with respect to a plane perpendicular to the substrate and the first boundary line, respectively.
In this case, the reflecting portions of the third and fourth optical members may be inclined at a predetermined angle with respect to the plane perpendicular to the substrate and the second boundary line, respectively.

The duplexer may further include a lens that collects the light emitted from the optical fiber.
In this case, the predetermined angle may be an angle substantially equivalent to an angle at which the light is collected by the lens.
Thereby, crosstalk between the respective light receiving elements can be effectively prevented.

In the duplexer, the substrate may further include fifth and sixth regions and fifth and sixth light receiving elements.
The fifth and sixth regions are formed on the sides of the first to fourth regions by the second boundary line and a third boundary line parallel to the first boundary line.
The fifth and sixth light receiving elements are provided in the fifth and sixth regions, respectively.
In this case, the wavelength selection unit of the first optical member may be arranged to be inclined with respect to a plane perpendicular to the substrate and the first boundary line.
In this case, the duplexer may further include a fifth optical member.
The fifth optical member constitutes a part of the second layer.
The fifth component member has a first mirror and is disposed corresponding to the fifth and sixth regions.
The first mirror guides the light reflected by the wavelength selection unit of the first optical member to the substrate side.
In this case, the third and fourth optical members may be provided corresponding to three regions in the direction along the second boundary among the first to sixth regions. .
In this case, each of the third and fourth optical members may have a second wavelength selection unit.
The second wavelength selection unit of the third and fourth optical members is provided corresponding to the fifth region or the sixth region, and is reflected by the wavelength selection unit of the first optical member. Of the light, light in different wavelength regions is selectively transmitted.

With such a configuration, the wavelength multiplexed light emitted from the optical fiber can be further divided into six demultiplexed waves, in addition to the above-described four demultiplexed waves.
Also in the present invention capable of 6-demultiplexing, the duplexer is formed by an optical member having the same configuration, so the structure is simple. Furthermore, also in the present invention, the light amount loss from the optical fiber to each light receiving element is about −6 dB for four openings.

In the duplexer, the substrate may further include seventh and eighth regions and seventh and eighth light receiving elements.
The seventh and eighth regions are formed on the sides of the first to fourth regions by the second boundary line and a fourth boundary line parallel to the first boundary line.
The seventh and eighth light receiving elements are provided in the seventh and eighth regions, respectively.
In this case, the wavelength selection unit of the second optical member may be arranged to be inclined with respect to a plane perpendicular to the substrate and the first boundary line.
In this case, the duplexer may further include a sixth optical member.
The sixth optical member constitutes a part of the second layer.
The sixth optical member has a second mirror and is disposed corresponding to the seventh and eighth regions.
The second mirror guides the light reflected by the wavelength selection unit of the second optical member to the substrate side.
In this case, the third and fourth optical members may be provided corresponding to four regions in the direction along the second boundary among the first to eighth regions. .
In this case, each of the third and fourth optical members may have a third wavelength selection unit.
The third wavelength selection unit of the third and fourth optical members is provided corresponding to the seventh region or the eighth region, and is reflected by the wavelength selection unit of the second optical member. Of these, light in different wavelength regions is selectively transmitted.

With such a configuration, it becomes possible to add the wavelength multiplexed light emitted from the optical fiber to the above-mentioned 6th demultiplexing and further to the 2nd demultiplexing, for a total of 8 demultiplexing.
Also in the present invention capable of demultiplexing, the duplexer is formed by an optical member having the same configuration, so that the structure is simple. Furthermore, also in the present invention, the light amount loss from the optical fiber to each light receiving element is about −6 dB for four openings.

A duplexer according to another aspect of the present invention includes a substrate, a first optical member, and a second optical member.
The substrate includes first and second regions and first and second light receiving elements.
The first and second regions are separated by a first boundary line.
The first and second light receiving elements are provided in the first and second regions, respectively.
The first optical member includes a first wavelength selection unit and a first reflection unit, and is stacked on the first region.
The first wavelength selection unit selectively transmits light in the first wavelength region out of light emitted from the optical fiber.
The first reflecting portion is provided to be inclined with respect to a plane parallel to the substrate and the first boundary line.
The second optical member includes a second wavelength selection unit and a second reflection unit, and is stacked on the second region.
The second wavelength selection unit selectively transmits light in a second wavelength region different from the first wavelength region in the emitted light.
The second reflecting portion is provided to be inclined with respect to the surface.

  As described above, according to the present invention, it is possible to provide a demultiplexer capable of demultiplexing wavelength-multiplexed light with a simple structure and capable of reducing light loss during demultiplexing. it can.

It is a perspective view showing a duplexer concerning one embodiment of the present invention. FIG. 4 is a magnification diagram of a lens included in the duplexer according to the embodiment of the present invention, a top view of the duplexer, and a side view of the duplexer. It is a front view which shows the board | substrate which the duplexer concerning one Embodiment of this invention has. It is a figure which shows the optical member which the duplexer concerning one Embodiment of this invention has. It is a figure which shows an example of the assembly process of the duplexer which concerns on one Embodiment of this invention. It is a figure which shows an example of the wavelength selection characteristic of the wavelength selection film | membrane which an optical member has. It is a figure for demonstrating the value of angle (theta) which the reflecting film which an optical member has, and is a top view of a duplexer. It is a figure for demonstrating operation | movement of the duplexer which concerns on one Embodiment of this invention. It is a figure for demonstrating operation | movement of the light reflected by the wavelength selection film | membrane. It is a figure which shows the duplexer which concerns on other embodiment of this invention. It is a front view which shows the board | substrate which the duplexer concerning other embodiment of this invention has. It is a figure which shows an example of the wavelength selection characteristic of the wavelength selection film | membrane which the splitter which concerns on other embodiment of this invention has. It is a figure which shows operation | movement of the duplexer which concerns on other embodiment of this invention.

<First Embodiment>
(Overall configuration of duplexer and configuration of each part)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a duplexer according to a first embodiment of the present invention. FIG. 2 is a magnification diagram of a lens included in the duplexer, a top view of the duplexer, and a side view of the duplexer.

  In addition, in each figure demonstrated in this specification, in order to display drawing easily, there exists a case different from an actual dimension about a splitter, each member, etc. which a splitter has.

  As shown in FIGS. 1 and 2, the duplexer 100 includes a lens 70 that collects wavelength-multiplexed light from an optical fiber 80 and a substrate 50 having four photodetectors 1, 2, 3, and 4. Yes. In addition, the duplexer 100 is stacked on the front side of the substrate 50, and the two optical members 30 and 40 constituting the first layer on the substrate 50 and further stacked on the front side of the two optical members 30 and 40. And two optical members 10 and 20 constituting the second layer on the substrate 50, and a package portion 60 for packaging each member.

  As the optical fiber 80, for example, a multimode fiber having a core diameter of 60 μm and a numerical aperture (NA (Numerical Aperture)) of 0.2 is used. The values of the core diameter and the numerical aperture (NA) of the optical fiber are not limited to the above values, and of course other values can be taken.

  The optical fiber 80 emits wavelength multiplexed light of four wavelengths (λ1, λ2, λ3, λ4) toward the lens 70. The four wavelengths (λ1 to λ4) of the wavelength multiplexed light are, for example, wavelengths in the visible light region, and the interval between the wavelengths is, for example, 50 nm. An antireflection film is formed on the end face of the optical fiber.

  The lens 70 is disposed, for example, at a position of 500 μm from the end face of the optical fiber 80. As the lens 70, a lens having a numerical aperture (NA) of 0.1 and a magnification of 1: 2. An antireflection film is formed on the surface of the lens 70.

  The two optical members 30 and 40 constituting the first layer on the substrate 50 are arranged so as to be aligned in the direction along the vertical axis direction (Y-axis direction), respectively (see FIG. 2C and FIG. 5 described later). . The two optical members 10 and 20 constituting the second layer (second layer) on the substrate 50 are arranged so as to be aligned in a direction along the horizontal axis direction (X-axis direction), respectively (FIG. 2B). FIG. 5).

The package unit 60 integrally packages the substrate 50, the four optical members 10, 20, 30, 40 and the lens 70. The package unit 60 integrally packages the members by, for example, resin-molding the members with a phenol resin or an epoxy resin.
In the region 61 between the lens 70 and the front surface of the optical member 10 and the optical member 20, no resin is present, and a hollow region 61 is formed.

  The distance from the lens 70 to the front surface of the optical member 10 and the optical member 20 is, for example, 100 μm. The thickness of the optical member 10 and the optical member 20 (second layer) is, for example, 200 μm, and the thickness of the optical member 30 and the optical member 40 (first layer) is, for example, 200 μm. . The distance from the lens to the front surface of the substrate is set to 500 μm, which is 100 μm + 200 μm + 200 μm. Note that the above-described values such as distance and thickness are not limited to the above-described values, and other values can of course be taken.

FIG. 3 is a front view showing the substrate.
As shown in FIG. 3, the planar outer shape of the substrate 50 is a substantially square shape, and the size of the substrate is, for example, 300 μm × 300 μm. The substrate 50 includes four regions 50a, 50b, 50c, and 50d that pass through the center of the substrate 50 in a vertical axis direction (Y-axis direction) boundary line 51 and a horizontal axis direction (X-axis direction) boundary line 52. It is divided into.

  The four photodetectors 1 to 4 are respectively provided corresponding to the four regions 50 a to 50 d divided by the boundary line 51 and the boundary line 52. The four photodetectors 1 to 4 are arranged in a 2 × 2 positional relationship. The size of the photodetectors 1 to 4 is, for example, 80 μm × 80 μm. The distance between the photodetectors 1 to 4 is, for example, 20 μm.

  Values such as the size of the substrate 50, the sizes of the photodetectors 1 to 4 and the distance between the photodetectors are not limited to the values described above, and other values can of course be taken.

  The front surface of the substrate 50 is a flat surface. That is, the front surface of the substrate 50 is a flat surface with no irregularities in the state where the photodetectors 1 to 4 are mounted (see FIG. 2).

Four markers 53, 54, 55, and 56 are provided on the front surface of the substrate 50. These four markers are provided at two points on the intersection of the edge of the substrate 50 and the boundary line 51 and two points on the intersection of the edge of the substrate 50 and the boundary line 52.
The four markers 53 to 56 are provided to allow the mounting apparatus (not shown) to recognize the boundary lines 51 and 52 when mounting the optical members 10 to 40 described later (see FIG. 5). .

  FIG. 4 is a diagram illustrating the optical member. 4A is a perspective view of the optical member, and FIG. 4B is a view of the optical member as seen from one direction.

  Since the four optical members 10 to 40 are typically similar in configuration and size, the optical member 10 will be described as a representative of the four optical members.

  As shown in FIG. 4, the optical member 10 has a rectangular parallelepiped shape, and the height (Y-axis direction) is, for example, 300 μm. The width (X-axis direction) is, for example, 150 μm, and the thickness (Z-axis direction) is, for example, 200 μm.

The height of the optical member 10 corresponds to the length of the substrate 50 in the vertical axis direction (Y-axis direction), and the width of the optical member 10 is half the length of the substrate 50 in the horizontal axis direction (X-axis direction). Corresponds to the length.
The values such as the height, width, and thickness of the optical member 10 are not limited to the above values.

  The optical member 10 includes a light transmissive substrate 11, a wavelength selection film 12 provided on the front side of the light transmissive substrate 11, and a reflective film 13 provided inside the light transmissive substrate 11.

  The wavelength selection film 12 is formed over the entire front surface of the light transmissive substrate 11. The wavelength selection film 12 selectively transmits light in a predetermined wavelength region out of wavelength multiplexed light emitted from the optical fiber 80 and reflects light in other wavelength regions. The wavelength selection characteristics of the wavelength selection film are different between the optical members 10, 20, 30, and 40. Details of the wavelength selection characteristics of the wavelength selection films of the optical members 10, 20, 30, 40 will be described later.

  The light transmissive substrate 11 is made of, for example, quartz glass, light transmissive resin (polycarbonate, acrylic resin), or the like. The light-transmitting substrate 11 includes a first substrate 11a having a quadrangular prism shape whose cross-sectional shape (ZX plane) is a trapezoid and a second substrate 11b having a triangular prism shape.

  The reflective film 13 is made of, for example, a metal with high reflectivity (for example, aluminum). The reflective film 13 is formed as a metal film on one surface of the first base material 11a or the second base material 11b by a vacuum deposition method or a sputtering method, and then the first base material 11a and the second base material 11 The base material 11b is joined to the inside of the light transmitting base material 11.

  The reflective film 13 is formed inside the light-transmitting substrate 11 so as to be inclined at a predetermined angle θ (see FIG. 4B) with respect to the YZ plane. Details of the angle θ at which the reflective film 13 is inclined will be described later.

(Assembly process of duplexer)
FIG. 5 is a diagram illustrating an example of an assembling process of the duplexer.
First, as shown in FIG. 5A, the optical member 40 is mounted on the front side of the substrate 50. The optical member 40 is mounted so as to correspond to the lower two regions 50b and 50c among the four regions of the substrate 50 divided into two rows and two columns by the boundary line 51 and the boundary line 52.

  In this case, in the optical member 40, the surface on which the wavelength selection film 42 is provided is the front surface, and the opposite side is the back surface. The back surface of the optical member is bonded to the two lower regions 50 b and 50 c of the substrate 50. In this case, the surface of the optical member 40 on which the reflective film 43 is provided is the upper surface.

  By mounting the optical member 40 as described above, the wavelength selection film 42 of the optical member 40 is arranged in parallel to the XY plane corresponding to the two lower regions 50b and 50c of the substrate 50. . Further, the reflective film 43 of the optical member 40 is disposed to be inclined at a predetermined angle θ (see FIG. 4B) with respect to the ZX plane.

  When the optical member 40 is mounted on the substrate 50, the optical member 30 is then mounted on the front side of the substrate 50 as shown in FIG. The optical member 30 is mounted so as to correspond to the two regions 50a and 50d on the upper side of the substrate 50 among the four regions of the substrate 50 divided into 2 rows and 2 columns.

  The surface of the optical member 30 on which the wavelength selection film 32 of the optical member 30 is provided is the front surface, and the back surface on the opposite side is bonded to the two regions 50a and 50b of the substrate. The optical member 30 has a lower surface on which the reflective film 33 is provided, and the lower surface of the optical member 30 and the upper surface of the optical member 40 are bonded.

  By mounting the optical member 30 as described above, the wavelength selection film 32 of the optical member 30 corresponds to the upper two regions 50a and 50d among the four regions of the substrate 50 divided into two rows and two columns. It arrange | positions in parallel with respect to XY plane. Further, the reflective film 33 of the optical member 30 is disposed with a predetermined angle θ inclined with respect to the ZX plane.

  Once the optical member 30 is mounted, the optical member 10 is then mounted on the front side of the optical member 30 and the optical member 40 as shown in FIG. The optical member 10 is mounted on the front side of the optical member 30 and the optical member 40 corresponding to the left two regions 50a and 50b among the four regions of the substrate 50 divided into 2 rows and 2 columns.

  In this case, in the optical member 10, the surface on which the wavelength selection film 12 is provided is the front surface, and the back surface on the opposite side is bonded to the optical members 30 and 40. In this case, the optical member 10 has a right side surface on which the reflective film 13 is provided.

  The wavelength selection film 12 of the optical member 10 is disposed in parallel to the XY plane corresponding to the two regions 50 a and 50 b on the left side of the substrate 50. In addition, the reflective film 13 of the optical member 10 is disposed at a predetermined angle θ with respect to the YZ plane.

  When the optical member 10 is mounted, the optical member 20 is then mounted on the front side of the optical member 30 and the optical member 40 as shown in FIG. The optical member 20 is mounted on the front side of the optical member 30 and the optical member 40 corresponding to the two right regions 50c and 50d among the four regions of the substrate 50 divided into two rows and two columns.

  In this case, the surface of the optical member 20 on which the wavelength selection film 22 is provided is the front surface, and the back surface, which is the opposite side, is bonded to the optical members 30 and 40. In this case, the optical member 20 is joined to the right side surface of the optical member 10 with the surface on which the reflective film 23 is provided being the left side surface.

  The wavelength selection film 22 of the optical member 20 is disposed in parallel to the XY plane corresponding to the two regions 50 a and 50 b on the left side of the substrate 50. Further, the reflective film 23 of the optical member 20 is disposed with a predetermined angle θ inclined with respect to the YZ plane.

  Mounting of the optical members 40, 30, 10, and 20 is performed by a mounting device (not shown) having an image sensor such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor. The mounting apparatus images the markers 53 to 56 provided on the front side of the substrate 50 by the imaging element. In the case of mounting the optical members 40 and 30, the mounting apparatus recognizes the boundary line 52 in the horizontal axis direction (in the X axis direction) from the captured image, and the recognized boundary line 52 and the optical members 40 and 30. Implementation is performed by matching the edge (long side). In the case of mounting the optical members 10 and 20, the mounting apparatus recognizes the boundary line 51 in the vertical axis direction (Y-axis direction) from the captured image, and the recognized boundary line 51 and the optical members 10 and 20. Implementation is performed by matching the edge (long side) of.

  Since the optical members 10 to 40 are sufficiently thin as described above (for example, 200 μm), the mounting apparatus is not out of focus when the markers 53 to 56 are imaged, and high-precision mounting is possible. is there.

  As described with reference to FIG. 5, the duplexer 100 according to the present embodiment includes four optical members 40, 30, 10, and 20 having the same configuration among the two boundary lines 51 and 52 of the substrate 50. It is formed by laminating two layers according to either one. Thus, the duplexer 100 according to the present embodiment is very simple to implement.

  In the description of FIG. 5, the optical member 40 and the optical member 30 are mounted in this order. However, the optical member 30 and the optical member 40 may be mounted in this order. In the description of FIG. 5, the optical member 10 and the optical member 20 are mounted in this order. However, the optical member 20 and the optical member 10 may be mounted in this order.

(Wavelength selective characteristics of wavelength selective film)
FIG. 6 is a diagram illustrating an example of wavelength selection characteristics of the wavelength selection films 12, 22, 32, and 42 included in the optical members 10, 20, 30, and 40.

  As shown in FIG. 6, the wavelength selection film 12 of the optical member 10 selectively selects light in the wavelength region of λ1 and λ2 among the wavelength multiplexed light of four wavelengths (λ1 to λ4) emitted from the optical fiber 80. Make it transparent. The wavelength selection film 12 is constituted by a dichroic filter in the visible light region made of a metal film, for example.

  The wavelength selection film 22 of the optical member 20 selectively transmits light in the wavelength regions of λ3 and λ4 among the wavelength multiplexed light of four wavelengths (λ1 to λ4). The wavelength selection film 22 is configured by a dichroic filter in the visible light region using a metal film, for example.

  The wavelength selection film 32 of the optical member 30 selectively transmits light in the wavelength regions of λ1 and λ4 among the wavelength multiplexed light of four wavelengths (λ1 to λ4). The wavelength selection film 32 is configured by, for example, a dichroic filter in the visible light region.

  The wavelength selection film 42 of the optical member 40 selectively transmits light in the wavelength region of λ2 and λ3 among the wavelength multiplexed light of four wavelengths (λ1 to λ4). The wavelength selection film 42 is composed of, for example, a dichroic filter in the visible light region.

  In this case, of the four wavelength multiplexed light emitted from the optical fiber 80, the light incident on the photodetector 1 can pass through the wavelength selection film 12 and can pass through the wavelength selection film 32. Therefore, the light has a wavelength of λ1.

  Similarly, the light incident on the photodetector 2 is light having a wavelength of λ2 because it is light having a wavelength that can be transmitted through the wavelength selection film 12 and transmitted through the wavelength selection film 42.

  Similarly, the light incident on the photodetector 3 is light having a wavelength of λ3 because it is light having a wavelength that can be transmitted through the wavelength selection film 22 and can be transmitted through the wavelength selection film 42.

  Similarly, the light incident on the photodetector 4 is light having a wavelength of λ4 because the light can be transmitted through the wavelength selection film 22 and transmitted through the wavelength selection film 32.

  In addition, the wavelength selection characteristic of each wavelength selection film | membrane 12, 22, 32, 42 is not restricted to an above-described combination. For example, the wavelength selection characteristics of the wavelength selection film 12 and the wavelength selection film 22 may be reversed. Similarly, the wavelength selection characteristics of the wavelength selection film 32 and the wavelength selection film 42 may be reversed.

  Alternatively, the wavelength selection film 12 may selectively transmit light in the wavelength region of λ1 and λ4, and the wavelength selection film 22 may selectively transmit light in the wavelength region of λ2 and λ3 (this wavelength selection characteristic is Or vice versa). In this case, the wavelength selection film 32 may selectively transmit light in the wavelength region of λ1 and λ2, and the wavelength selection film 42 may selectively transmit light in the wavelength region of λ3 and λ4 (this wavelength selection characteristic). May be reversed).

The wavelength selection characteristics of 12, 22, 23, and 24 of each wavelength selection film will be described in more detail.
The wavelength selection characteristics of the two wavelength selection films 12 and 22 adjacent to each other are such that two of the four wavelengths complement each other. Similarly, the wavelength selection characteristics of the two wavelength selection films 32 and 42 adjacent to each other are such that two of the four wavelengths complement each other.

  Further, the wavelength selection characteristics of the wavelength selection films 32 and 42 will be described in relation to the wavelength selection characteristics of the wavelength selection films 12 and 22. The wavelength selection film 32 selectively transmits two wavelengths that are a combination of one of the two wavelengths transmitted through the wavelength selection film 12 and one of the two wavelengths transmitted through the wavelength selection film 22. The wavelength selection film 42 has one wavelength out of two wavelengths transmitted through the wavelength selection film 12 (this one wavelength is one wavelength not transmitted through the wavelength selection film 32) and 2 transmitted through the wavelength selection film 22. Two wavelengths in combination with one of the wavelengths (the one wavelength is one wavelength that is not transmitted through the wavelength selection film 32) are selectively transmitted.

(Inclination angle of reflective film)
Next, details about the angle θ at which the reflection films 13, 23, 33, and 43 included in the optical members 10, 20, 30, and 40 are inclined will be described.

  FIG. 7 is a diagram for explaining the value of the angle θ at which the reflective film of the optical member is inclined, and is a top view of the duplexer. FIG. 7A is a diagram showing light rays when the reflective films 13 and 23 of the optical members 10 and 20 are not provided. FIG. 7B is a diagram showing light rays when the tilt angle θ with respect to the YZ plane of the reflective films 13 and 23 included in the optical members 10 and 20 is 0 °. FIG. 7C is a diagram showing light rays when the tilt angle θ with respect to the YZ plane of the reflective films 13 and 23 included in the optical members 10 and 20 is 5.7 ° (equivalent to NA 0.2). It is. FIG. 7B is a diagram showing light rays when the inclination angle θ of the reflective films 13 and 23 of the optical members 10 and 20 with respect to the YZ plane is 11.3 ° (equivalent to NA 0.1). It is.

  As shown in FIG. 7A, when the optical films 10 and 20 are not provided with the reflective films 13 and 23, they are close to each other in the horizontal axis direction (Y-axis direction) as indicated by the thick arrows in the figure. Leaked light enters between the two photodetectors 1 and 4 (or the photodetectors 2 and 3 and omitted in the description of FIG. 7 below). As a result, crosstalk occurs between the two photodetectors 1 and 4 that are close to each other.

  As shown in FIG. 7B, even when the reflective films 13 and 23 are provided on the optical members 10 and 20, the angle θ of the reflective films 13 and 23 with respect to the YZ plane is 0 °. In this case, leaked light enters between the photodetectors 1 and 4 as indicated by thick arrows in the figure. Therefore, it cannot be said that it is sufficient as a countermeasure against leakage light.

  As shown in FIG. 7C, when the inclination angle θ of the reflective films 13 and 23 with respect to the YZ plane is 11.3 ° (corresponding to a numerical aperture of 0.2), As indicated by the arrows, there is no leakage light that enters between the photodetectors 1 and 4, but light enters the outside of the photodetectors 1 and 4.

  As shown in FIG. 7D, when the tilt angle θ of the reflective films 13 and 23 with respect to the YZ plane is 5.7 ° (equivalent to NA 0.1), It is possible to regulate the incidence of leaked light. That is, by making the inclination angle θ of the reflecting films 13 and 23 with respect to the YZ plane equal to or similar to the condensing angle by the lens 70, it is possible to restrict the generation of leakage light. . Further, in this case, it is possible to restrict light from entering the outside of the photodetectors 1 and 4. Thereby, the best countermeasure against leakage light and the light collecting effect can be obtained.

  In the description of FIG. 7, the description has been made centering on the inclination angle θ of the reflection films 13 and 23 of the optical members 10 and 20 with respect to the YZ plane. The same applies to the inclination angle θ with respect to the −X plane. That is, the inclination angle θ of the reflecting films of the optical members 30 and 40 with respect to the ZX plane is equal to or similar to the condensing angle by the lens 70 as in FIG. Leaked light can be prevented from entering between the adjacent photodetectors 1 and 2 (or the photodetectors 4 and 3). Furthermore, light can be appropriately collected in the photodetectors 1 and 2.

  Due to the light condensing effect on the photodetectors 1 to 4 by the reflection films 13, 23, 33, and 43 as described above, the photodetectors 1 to 4 can be reduced in size (in this embodiment, 80 μm × 80 μm). If the size of the photodetectors 1 to 4 is 100 μm × 100 μm or less, the parasitic capacitance of the depletion layer of the photodetector can be suppressed, and the frequency characteristics of the photodetector of about 10 to 100 Gbps can be ensured.

  Further, due to the light condensing effect of the reflective films 13, 23, 33, and 43, the interval between the adjacent photodetectors can be widened (in this embodiment, 20 μm). Thereby, leakage of electrons between the depletion layers of the photodetectors close to each other can be prevented.

(Description of operation)
Next, the operation of the duplexer will be described.

  FIG. 8 is a diagram for explaining the operation of the duplexer. FIG. 8A is a top view of the duplexer, and FIG. 8B is a side view of the duplexer. FIG. 8C is a cross-sectional view of the duplexer on the XY plane.

  Wavelength multiplexed light of four wavelengths (λ1 to λ4) is emitted from the light emitted from the optical fiber 80 at an angle of 0.2, and is collected by the lens 70 having a numerical aperture of 0.1 at an angle of 0.1. To be lighted.

  The wavelength multiplexed light of 4 wavelengths collected by the lens 70 is incident on the wavelength selection film 12 of the optical member 10 and the wavelength selection film of the optical member 20 (see FIG. 8C). The wavelength selection film 12 of the optical member 10 selectively transmits light of two wavelengths λ1 and λ2 out of wavelength multiplexed light of four wavelengths (λ1 to λ4) and reflects light of other two wavelengths λ3 and λ4. . The wavelength selection film 22 of the optical member 20 selectively transmits light of two wavelengths λ3 and λ4 out of the four wavelengths and reflects the other two wavelengths λ1 and λ2.

  The light transmitted through the wavelength selection film 12 of the optical member 10 and the wavelength selection film 22 of the optical member 20 is demultiplexed by two wavelengths in the left-right direction when viewed from the front side of the duplexer 100.

  Wavelength multiplexed light of two wavelengths λ1 and λ2 that has passed through the optical member 10 is incident on the left side of the wavelength selection film 32 of the optical member 30 and the wavelength selection film 42 of the optical member 40. In the wavelength multiplexed light incident on the left side of the wavelength selection film 32 and the wavelength selection film 42, a part of the right side is reflected by the reflection film 13 of the optical member 10, and a part of the right side is in the vertical axis direction (Y It is in a state of being folded along the axial direction (see FIG. 8C).

  The wavelength multiplexed light of the two wavelengths λ3 and λ4 transmitted through the optical member 20 is incident on the right side of the wavelength selection film 32 of the optical member 30 and the wavelength selection film 42 of the optical member 40. In the wavelength multiplexed light that is incident on the right side of the wavelength selection film 32 and the wavelength selection film 42, a part of the left side is reflected by the reflection film 23 of the optical member 20, so a part of the left side is in the vertical axis direction It is in a state of being folded along the axial direction (see FIG. 8C).

  The wavelength selection film 32 selectively transmits light having a wavelength of λ1 and reflects light having a wavelength of λ2 out of wavelength multiplexed light of two wavelengths λ1 and λ2 incident on the left side. In addition, the wavelength selection film 32 selectively transmits light having a wavelength of λ4 and reflects light having a wavelength of λ3 out of wavelength multiplexed light of two wavelengths λ3 and λ4 incident on the right side.

  The wavelength selection film 42 selectively transmits light having a wavelength of λ2 out of wavelength multiplexed light of two wavelengths λ1 and λ2 incident on the left side and reflects light having a wavelength of λ1. The wavelength selection film 42 selectively transmits light having a wavelength of λ3 and reflects light having a wavelength of λ4 out of wavelength multiplexed light of two wavelengths λ3 and λ4 incident on the right side.

  The light transmitted through the wavelength selection film 32 of the optical member 30 and the wavelength selection film 42 of the optical member 40 is divided into two in the left-right direction when viewed from the front side of the duplexer 100, and further divided into two in the vertical direction. A total of four quarters (2 × 2) is generated.

  The light of wavelength λ1 transmitted through the left side of the wavelength selection film 32 is incident on the photodetector 1 such that a part of the lower side is folded along the horizontal axis direction by the reflection film 33 of the optical member 30 (FIG. 8 (C)). The light having the wavelength of λ2 transmitted through the left side of the wavelength selection film 42 is incident on the photodetector 2 so that a part of the upper side is folded along the horizontal axis direction by the reflection film 43 of the optical member 40. The light having the wavelength of λ3 transmitted through the right side of the wavelength selection film 42 is incident on the photodetector 3 so that a part of the upper side is folded along the horizontal axis direction by the reflection film 43. The light having the wavelength of λ4 transmitted through the right side of the wavelength selection film 32 is incident on the photodetector 4 such that a part of the lower side is folded along the horizontal axis direction by the reflection film 33.

  As described above, the duplexer 100 according to the present embodiment uses the wavelength selection films 12 and 22 and the wavelength selection films 32 and 42 to superimpose four wavelengths of wavelength multiplexed light emitted from the optical fiber 80. Each wavelength is divided into four, and light of each wavelength can be appropriately incident on each of the photodetectors 1, 2, 3, and 4.

  In the present embodiment, the light amount loss from the optical fiber 80 to each of the photodetectors 1, 2, 3, and 4 is about −6 dB of the wavelength division multiplexed light divided into four apertures, and the light amount loss can be reduced.

  Furthermore, since the inclination angle θ of the reflection film is appropriately set, as described above, the best countermeasure against leakage light and the light collecting effect can be obtained. Furthermore, the duplexer according to the present embodiment is formed by laminating optical members 10, 20, 30, and 40 having the same configuration in two layers on the substrate. Thus, in this embodiment, since the structure is extremely simple, the mounting is simplified and the cost can be reduced.

Next, the operation of the light reflected by each wavelength selection film 12, 22, 23, 24 will be described.
As described above, each wavelength selection film selectively transmits light of two predetermined wavelengths among the wavelength multiplexed light of four wavelengths (λ1, λ2, λ3, λ4) and reflects the other two wavelengths of light. Let Hereinafter, the operation of the reflected light will be described.

  FIG. 9 is a diagram for explaining the operation of light reflected by the wavelength selection film. FIG. 9A is a top view of the duplexer, and FIG. 9B is a side view.

  Here, since the wavelength selection film 12 and the wavelength selection film 22 and the wavelength selection film 32 and the wavelength selection film 42 have complementary wavelength selection characteristics, the movement of reflected light is the same. Therefore, the movement of light reflected by the wavelength selection film 12 and the movement of light reflected by the wavelength selection film 32 will be described representatively.

  As shown in FIG. 9A, the reflected light reflected by the wavelength selection film 12 of the optical member 10 may be repeatedly reflected from the surface of the lens 70 and enter the wavelength selection film 22 side. However, in this case, since the antireflection film is formed on the lens 70 and the reflectance is suppressed to several percent as described above, the ratio of the reflected light to the regular signal is almost a problem as the SN ratio. Must not.

  Further, as shown in FIG. 9A, the reflected light reflected by the surface of the wavelength selection film 12 may be reflected by the end face of the optical fiber 80 and enter the wavelength selection film 22 side. However, even in this case, since the antireflection film is formed on the end face of the optical fiber 80 as described above and the reflectance is suppressed to several percent, there is almost no problem with the SN ratio. Moreover, the light reflected by the wavelength selection film 12 is light having wavelengths of λ3 and λ4, and is not a noise but a normal signal for the wavelength selection film 22.

  As shown in FIG. 9B, the reflected light reflected by the wavelength selection film 32 may be reflected by the end face of the optical fiber 80 and enter the wavelength selection film 42 side. However, in this case, as described above, an antireflection film is formed on the end face of the optical fiber 80, and the reflectance is suppressed to several percent.

The light that is reflected on the wavelength selection film 32, reflected on the end face of the optical fiber 80, passes through the wavelength selection film 42, and is incident on the photodetector 3 is not affected by the normal signal. Multipath delay is maximum. This delay time is 5.33 ps according to the following equation (1).
(500 + 100 + 200) (μm) × 2 / (3 · 10 ⁸ ) (m / s) = 5.33 (ps) (1)

In this case, the reception at 10 Gbps is 0.0533 (ps) according to the following equation (2), and the reception at 100 Gbps is approximately 0.533 according to the following equation (3).
5.33 (ps) / 100 (ps) = 0.0533 (ui) (2)
5.33 (ps) / 10 (ps) = 0.533 (ui) (3)
Therefore, this is a level that does not hinder the required aperture value 0.5 (ui) of the normal reception waveform.

<Second Embodiment>
(Overall configuration of duplexer and configuration of each part)
Next, a second embodiment of the present invention will be described. In the description of the second embodiment, members having the same configurations and functions as those of the first embodiment described above are denoted by the same reference numerals, and description thereof is simplified or omitted.

  FIG. 10 is a diagram illustrating a duplexer according to the second embodiment. FIG. 10A is a top view showing the duplexer 200, and FIG. 10B is a side view showing the duplexer 200. FIG. 10C is a cross-sectional view of the duplexer 200 on the XY plane.

  As shown in FIG. 10, the duplexer 200 includes a lens 70 that collects wavelength multiplexed light emitted from the optical fiber 80, a substrate 170 having eight photodetectors 81 to 88, and a first layer on the substrate 170. The optical member 130 and the optical member 140 are included. In addition, the duplexer 200 includes an optical member 110, an optical member 120, an optical member 150, and an optical member 160 that constitute a second layer on the substrate 170, and a package unit 180 that packages the above-described members.

  In the second embodiment, the optical fiber 80 emits wavelength multiplexed light of 8 wavelengths (λ1 to λ8).

  FIG. 11 is a front view showing the substrate 170. The size of the substrate 170 is, for example, 300 μm × 600 μm. The substrate 170 is divided into eight regions 50 a to 50 h by three boundary lines 51, 62, 63 in the vertical axis direction and a boundary line 52 in the horizontal axis direction. The substrate 170 is divided into 8 regions of 2 rows and 4 columns.

  Photo detectors 81 to 88 are provided in the eight regions 50a to 50h of the substrate 170, respectively. The size of the four photodetectors 83 to 86 provided in the four central regions 50a to 50d is, for example, 80 μm × 80 μm, and the four photodetectors 81 and 82 provided in the four left and right regions 50e to 50h, The sizes of 87 and 88 are, for example, 80 μm × 100 μm. Note that the size of the substrate 170 and the sizes of the photodetectors 81 to 88 are not particularly limited, and various values can be taken.

  Referring to FIG. 10 again, the optical member 130 constituting the first layer on the substrate 170 is stacked on the substrate 170 corresponding to the four regions 50e, 50a, 50d, and 50h on the upper side of the substrate 170. The optical member 130 includes three wavelength selection films 131, 132, and 133 that are provided on the front side and have different wavelength selection characteristics. Further, the optical member 130 has a reflection film 134 provided on the lower surface side so as to be inclined 5.7 ° (equivalent to NA 0.1) with respect to the ZX plane.

  The wavelength selection film 131 is disposed corresponding to the upper left region 50e of the substrate 170, and the wavelength selection film 132 is disposed corresponding to the two regions 50a and 50d at the upper center of the substrate. The wavelength selection film 133 is disposed corresponding to the upper right region 50 h of the substrate 170.

  An optical member 140 constituting the first layer on the substrate 170 is provided below the optical member 130. The optical member 140 is stacked on the substrate 170 so as to correspond to the four regions 50f, 50b, 50c, and 50g on the lower side of the substrate 170. The optical member 140 has three wavelength selection films 141, 142, and 143 having different wavelength selection characteristics on the front side, and a reflection film 144 that is provided on the upper surface side with an inclination of 5.7 ° with respect to the Z-X plane. Have.

  The wavelength selection film 141 is disposed corresponding to the lower left region 50 f of the substrate 170, and the wavelength selection film 142 is disposed corresponding to the two lower regions 50 b and 50 c of the substrate 170. The wavelength selection film 143 is disposed corresponding to the lower right region 50g of the substrate 170.

  The optical member 110 constituting the second layer on the substrate 170 has a wavelength selection film 112 provided in an inclined manner with respect to the XY plane, and 5 on the right side with respect to the YZ plane. It has a reflective film 113 provided with an inclination of 7 degrees. The optical member 110 is provided corresponding to the two regions 50 a and 50 b of the substrate 170. The angle at which the wavelength selection film 112 is inclined is, for example, 45 °, but is not limited thereto.

  The optical member 120 provided on the right side surface side of the optical member 110 has a wavelength selection film 122 provided in an inclined manner with respect to the XY plane inside, and 5. on the left side surface with respect to the YZ plane. It has a reflective film 123 provided with an inclination of 7 °. The optical member 120 is provided corresponding to the two regions 50 c and 50 d of the substrate 170. The angle at which the wavelength selection film 122 is inclined is, for example, 45 degrees, but is not limited thereto.

  The optical member 150 provided on the left side surface side of the optical member 110 includes a mirror 151 provided therein with an inclination with respect to the XY plane. The optical member 150 is provided corresponding to the two regions 50e and 50f on the left side of the substrate 170. The angle at which the mirror 151 is inclined is, for example, 45 °, but is not limited thereto. The mirror 151 has a function of guiding light reflected by the wavelength selection film 112 of the optical member 110 to the substrate 170 side.

  The optical member 160 provided on the right side surface of the optical member 120 includes a mirror 161 provided in an inclined manner with respect to the XY plane. The optical member 160 is provided corresponding to the two regions 50g and 50h on the right side of the substrate 170. The angle at which the mirror 161 is inclined is, for example, 45 °, but is not limited thereto. The mirror 161 guides the light reflected by the wavelength selection film 122 of the optical member 120 to the substrate 170 side.

  The substrate 170, the optical members 110 to 160, and the lens 70 are integrally packaged by the package unit 180. A region 181 between the lens 70 and the front surfaces of the optical member 110 and the optical member 120 is a hollow region 181.

FIG. 12 is a diagram illustrating an example of wavelength selection characteristics of the wavelength selection film.
As shown in FIG. 12, the wavelength selection film 112 selectively transmits light having wavelengths λ <b> 3 and λ <b> 4 among the eight wavelength multiplexed light emitted from the optical fiber 80. The wavelength selection film 122 selectively transmits light having wavelengths λ5 and λ6. The wavelength selection film 132 selectively transmits light with wavelengths λ1, λ2, λ3, λ6, λ7, and λ8, and the wavelength selection film 142 of the optical member 140 selectively transmits light with wavelengths λ4 and λ5. Let The wavelength selection film 131 is λ1 light, the wavelength selection film 133 is λ8 wavelength light, the wavelength selection film 141 is λ2 and λ3 wavelength light, and the wavelength selection film 143 is λ6 and λ7. Selectively transmits light having a wavelength of.
In addition, the combination of the wavelength selection characteristics of each wavelength selection film can be changed as appropriate.

(Description of operation)
FIG. 13 is a diagram illustrating the operation of the duplexer. FIG. 13A is a top view of the duplexer 200, and FIG. 13B is a side view of the duplexer 200.
In the description of FIG. 13, the operation of the duplexer will be described with reference to FIG.

  Wavelength multiplexed light of 8 wavelengths (λ1 to λ8) emitted from the optical fiber is collected by the lens 70 and provided at a predetermined angle with respect to the XY plane and a wavelength selection film 112 and a wavelength selection film 122 is incident.

  The wavelength selection film 112 transmits light having wavelengths λ3 and λ4 among the incident wavelength multiplexed light having eight wavelengths, and reflects light having wavelengths λ1, λ2, λ5, λ6, λ7, and λ8.

  The light reflected by the wavelength selection film 112 is guided to the mirror 151 side, reflected by the mirror 151, and travels toward the substrate 170 side. This light is incident on the wavelength selection film 131 or the wavelength selection film 141. The wavelength selection film 131 selectively transmits the light having the wavelength of λ1 among the wavelength multiplexed light (λ1, λ2, λ5, λ6, λ7, λ8) reflected by the wavelength selection film 112 and guided by the mirror 151. , Reflect light of other wavelengths. As a result, light having a wavelength of λ1 is incident on the photodetector 81.

  The wavelength selection film 141 selectively transmits light having a wavelength of λ2 out of wavelength multiplexed light (λ1, λ2, λ5, λ6, λ7, λ8) reflected by the wavelength selection film 112 and guided by the mirror 151. , Reflect light of other wavelengths. As a result, light having a wavelength of λ 2 is incident on the photodetector 82.

  The light (λ3, λ4) transmitted through the wavelength selection film 112 is incident on the wavelength selection film 132 or the wavelength selection film 142. The wavelength selection film 132 selectively transmits the light having the wavelength λ3 and reflects the light having the wavelength λ4. As a result, light having a wavelength of λ3 is incident on the photodetector 83. The wavelength selection film 142 selectively transmits light having a wavelength of λ4 and reflects light having a wavelength of λ3. As a result, light having a wavelength of λ4 is incident on the photodetector 84.

  The wavelength selection film 122 transmits light of wavelengths λ5 and λ6 out of the incident wavelength multiplexed light of eight wavelengths and reflects light of wavelengths λ1, λ2, λ3, λ4, λ7, and λ8.

  The light (λ5, λ6) transmitted through the wavelength selection film 122 is incident on the wavelength selection film 132 or the wavelength selection film 142. The wavelength selection film 142 selectively transmits light having a wavelength of λ5 and reflects light having a wavelength of λ6. As a result, light having a wavelength of λ5 is incident on the photodetector 85. The wavelength selection film 132 selectively transmits light having a wavelength of λ6 and reflects light having a wavelength of λ5. As a result, light of λ6 is incident on the photodetector 86.

  The light (λ1, λ2, λ3, λ4, λ7, λ8) reflected by the wavelength selection film 122 is guided to the mirror 161 side, is reflected by the mirror 161, and enters the wavelength selection film 133 or the wavelength selection film 143. . The wavelength selection film 143 selectively transmits light having a wavelength of λ7 among the light (λ1, λ2, λ3, λ4, λ7, λ8) guided to the mirror 161 and reflects other light. The wavelength selection film 133 selectively transmits light having a wavelength of λ8 out of the light guided to the mirror 161 and reflects light having other wavelengths.

As described above, the duplexer 200 according to the second embodiment divides the wavelength-multiplexed light of 8 wavelengths emitted from the optical fiber 80 by 8 by wavelength by superimposing the two wavelength selection films, Light of a wavelength can be appropriately incident on each of the photodetectors 81-88.
Further, since the duplexer 200 is configured with a simple structure, the mounting is simplified and the cost can be reduced.

  Furthermore, also in this embodiment, the light amount loss from the optical fiber 80 to each of the photodetectors 81 to 88 is about −6 dB of the four openings, and the light amount loss can be reduced.

<Various modifications>
In the first embodiment described above, it has been described that the optical members 30 and 40 constitute the first layer on the substrate 50, and the optical members 10 and 20 constitute the second layer on the substrate 50. However, the present invention is not limited to this, and the optical members 10 and 20 may be the first layer, and the optical members 30 and 40 may be the second layer.

  In the description of FIG. 4 described above, the optical member 10 has been described as having a laminated structure of the first base material 11a and the second base material 11b. However, the second substrate 11b of the optical member 10 may not be provided. That is, the portion where the second base material 11b is provided is a region where light does not reach, and thus may not be provided. The same applies to the optical members 20, 30, 40, 110, 120, 130, and 140.

  In each of the above-described embodiments, examples of the fourth and eighth demultiplexing have been described. However, the duplexer may be a two-splitter. That is, the duplexer may be composed of two optical members (for example, optical members 30 and 40). Alternatively, it may be a third branch, a fifth branch, a sixth branch, a seventh branch, or the like. For example, in the case of the 6th branch, in the duplexer 200 of the second embodiment described above, there is a form in which either one of the left and right regions sandwiching the four central regions of the substrate 170 is not provided. Alternatively, the duplexer can be configured to have a wavelength of 9 or more (for example, 16th wavelength) by overlapping wavelength selection characteristics.

  In each of the above-described embodiments, the optical fiber 80 has been described as a multimode fiber. However, the present invention is not limited to this, and a single mode fiber may be used.

1, 2, 3, 4, 81, 82, 83, 84, 85, 86, 87, 88 ... Photodetector 10, 20, 30, 40, 110, 120, 130, 140, 150, 160 ... Optical member 12, 22 , 32, 42, 112, 122, 131, 132, 133, 141, 142, 143 ... wavelength selection film 13, 23, 33, 43, 113, 123, 134, 144 ... reflective film 50, 170 ... substrate 50a, 50b , 50c, 50d, 50e, 50f, 50g, 50h ... area 51, 52, 62, 63 ... boundary line 70 ... lens 80 ... optical fiber 100, 200 ... duplexer

Claims (7)

First to fourth regions divided by a first boundary line and a second boundary line orthogonal to the first boundary line; and first to fourth light receiving elements respectively provided in the respective regions; A substrate having
A first layer stacked on the substrate;
A second layer stacked on the first layer;
Wavelength selection units that are first and second optical members that respectively constitute part of the second layer, and selectively transmit light in different wavelength regions out of light emitted from the optical fiber. Each of the first and second optical members disposed corresponding to two regions adjacent to each other in the direction along the first boundary line,
3rd and 4th optical members that constitute a part of the first layer, respectively, and selectively transmit light in different wavelength regions among the light transmitted through the first and second optical members. A first wavelength selection unit that transmits the first and second optical elements, and the third and fourth optical elements respectively disposed corresponding to two regions adjacent to each other in the direction along the second boundary line. A duplexer comprising: a member; The duplexer according to claim 1, wherein
Each of the first and second optical members further includes a reflective portion in a portion close to each other,
Each of the third and fourth optical members further includes a reflection portion in a portion close to each other. The duplexer according to claim 2, wherein
The reflecting portions of the first and second optical members are inclined at a predetermined angle with respect to the plane perpendicular to the substrate and the first boundary line, respectively.
The duplexers in which the reflecting portions of the third and fourth optical members are inclined at a predetermined angle with respect to a plane perpendicular to the substrate and the second boundary line, respectively. The duplexer according to claim 3, wherein
A lens for collecting the light emitted from the optical fiber;
The duplexer is an angle that is substantially equal to an angle at which the light is collected by the lens. The duplexer according to claim 1, wherein
The substrate includes fifth and sixth regions formed on the sides of the first to fourth regions by the second boundary line and a third boundary line parallel to the first boundary line. And fifth and sixth light receiving elements respectively provided in the fifth and sixth regions,
The wavelength selection unit of the first optical member is disposed to be inclined with respect to a plane perpendicular to the substrate and the first boundary line,
The duplexer is
A fifth optical member constituting a part of the second layer, the first optical member having a first mirror that guides the light reflected by the wavelength selection unit of the first optical member toward the substrate; A fifth optical member disposed corresponding to the fifth and sixth regions;
The third and fourth optical members are respectively provided corresponding to three regions in the direction along the second boundary among the first to sixth regions, and the fifth region or the fifth region is provided. 6 is a second wavelength selection unit provided corresponding to the region 6, and selectively transmits light in different wavelength regions among the light reflected by the wavelength selection unit of the first optical member. A duplexer having a second wavelength selector. The duplexer according to claim 5, wherein
The substrate includes seventh and eighth regions formed on the sides of the first to fourth regions by the second boundary line and a fourth boundary line parallel to the first boundary line. And seventh and eighth light receiving elements respectively provided in the seventh and eighth regions,
The wavelength selection unit of the second optical member is disposed to be inclined with respect to a plane perpendicular to the substrate and the first boundary line,
The duplexer is
A sixth optical member constituting part of the second layer, the first optical member having a first mirror that guides light reflected by the wavelength selection unit of the second optical member toward the substrate; A sixth optical member disposed corresponding to the seventh and eighth regions;
The third and fourth optical members are respectively provided corresponding to four regions in the direction along the second boundary among the first to eighth regions, and the seventh region or the eighth region is provided. 8 is a third wavelength selection unit provided corresponding to the region 8, and selectively transmits light in different wavelength regions among the light reflected by the wavelength selection unit of the second optical member. Each has a third wavelength selector A substrate having first and second regions partitioned by a first boundary line, and first and second light receiving elements respectively provided in the first and second regions;
A first wavelength selection unit that selectively transmits light in a first wavelength region out of light emitted from the optical fiber; and a surface that is inclined with respect to a plane parallel to the substrate and the first boundary line. A first optical member that is provided on the first region;
Of the emitted light, a second wavelength selection unit that selectively transmits light in a second wavelength region different from the first wavelength region, and a second wavelength selection unit provided to be inclined with respect to the surface And a second optical member that is stacked on the second region.