JPH11125732A - Optical element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate usual connection work between an optical fiber and an optical waveguide by constituting an optical coupler with an optical fiber coupler provided with first, second optical fibers fixedly provided on the upper surface of a substrate. SOLUTION: As the optical coupler, the optical fiber coupler 12 provided with the first optical fiber 12A and the second optical fiber 12B fixedly provided on the upper surface of the substrate made of e.g. glass is used. The optical fiber coupler 12 is constituted of an input port 12a for inputting light of different wavelengths, e.g. the light of a first wavelength and the light of a second wavelength, a drop port 12b for taking out the light of the prescribed wavelength, e.g. the light of the first wavelength, a coupler part 12c for uniting the first optical fiber 12A and the second optical fiber 12B and output ports 12d, 12e for taking out the light of the wavelength excepting the light of the prescribed wavelength, e.g. the light of the second wavelength. Thus, the fiber coupler fixedly provided on the substrate is applied in-place of the optical waveguide formed on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to adding (adding: (ADD)) and extracting (dropping: (DROP)) a wavelength-multiplexed optical signal used for telephone communication in an optical subscriber system. For optical device and method for manufacturing the same.

[0002]

2. Description of the Related Art There is an optical subscriber system for communicating between each home and a communication center using an optical fiber. This system includes an optical signal for adding a new optical signal to a wavelength multiplexed optical signal used for telephone communication or the like between an office side circuit (OSU) and a user, and for dropping a predetermined optical signal. Element (ONU: Optical Network Unit (Optical Ne
twork Unit)) is used. As this ONU,
There is an optical device described in Document 1 (1996-IEICE General Conference Proceedings C-223). This optical element is a four-terminal one-input three-output optical coupler as an optical coupling means, that is, a four-terminal one provided especially on a substrate.
An optical waveguide type optical star coupler having three inputs and three outputs is used.
This optical element is an optical element employing a filter reflection type wavelength division multiplexing (WDM) in which a filter is provided in the star coupler. In the case of this optical element (ONU), a substrate is used in which a branch-type optical waveguide in which two optical waveguides are combined into one is formed in advance. Of this board,
At a coupling point where the two optical waveguides are combined into one, a cut groove integrated with the substrate is provided in the optical waveguide, and a filter is inserted into the cut groove. Then, optical signals of two different wavelengths are input from one input terminal, and only an optical signal of a predetermined wavelength is totally reflected by this filter and propagated to one output terminal. Then, light of another wavelength is transmitted through the filter and propagated to another output terminal to achieve a required function.

[0003]

However, in the above-mentioned conventional ONU, there are the following problems in the connection between the optical fiber and the optical waveguide of the ONU. That is, the connection between the optical waveguide and the optical fiber is performed by the following process, for example. First, the optical fiber is connected to an optical waveguide in a state where light is input to the optical fiber. At the time of the connection, the connection operation is repeated as many times as it can be confirmed that 100% of the light energy from the optical fiber is transmitted to the optical waveguide.
Since this adjustment is a subtle micron work,
You will have to work very hard.

[0004] Therefore, there has been a demand for the emergence of an optical element which does not require the connection between the optical fiber and the optical waveguide.

Further, in a filter reflection type wavelength division multiplexing optical element in which a filter is provided in a conventional star coupler, a new type of ONU using an optical directional coupler instead of the star coupler has appeared. Was desired.

[0006]

In order to solve these problems, according to the optical element of the present invention, a filter reflection type wavelength division multiplexing optical system in which a filter is provided in an optical coupler of four terminals, one input and three outputs. The device is characterized in that the optical coupler is constituted by an optical fiber coupler having first and second optical fibers fixed to the upper surface of the substrate.

According to this structure, a fiber coupler fixed to the substrate can be applied to the optical element instead of the optical waveguide formed on the substrate. Therefore, according to the optical element of the present invention, since the optical fiber itself is fixed to the substrate from the beginning, the connection work with the optical fiber as in the related art is unnecessary.

In practicing the present invention, preferably, the filter is a plate-type wavelength separation filter, and the optical power of the incident light propagating through the first optical fiber and the second optical fiber due to the incident light. When the positions on the first and second optical fibers where the optical power of the generated distributed light becomes equal to the first point and the second point, respectively, the substrate passes through the first and second points and passes through the substrate. It is preferable to arrange the filter so as to be substantially perpendicular to the upper surface of the filter.

With this configuration, the incident light propagating through the first fiber is reflected toward the second fiber in mirror symmetry about the straight line connecting the first point and the second point as an axis. You. Therefore, it is possible to realize an optical element of a filter reflection type wavelength division multiplex system using an optical directional coupler provided with a filter.

In this case, it is preferable that the position where the optical power of the incident light and the optical power of the distributed light become equal first is selected as the first point and the second point.

There are several places where the power of the incident light becomes equal to the optical power of the distributed light during the propagation of the incident light of the optical fiber coupler. Thus, by first setting a point where a filter is provided at a position where both optical powers are equal to each other, it is possible to obtain reflected light with the least optical power loss.

In practicing the present invention, it is preferable that a cut groove reaching the substrate by cutting the optical fiber coupler be provided, and a filter be disposed in the cut groove.

Further, a new upper cover for covering the optical fiber coupler on the substrate may be newly provided, and a filter may be implanted in the upper cover so that the filter can be inserted into the cut groove when the upper cover is put on the substrate. .

With this configuration, it is not necessary to inject an adhesive into the cut groove in order to connect the filter to the cut groove, so that light transmitted through the adhesive fixed to the filter becomes less than the material of the adhesive. Problems such as a change in the refractive index of the filter due to deterioration due to temperature or the like are eliminated.

In this case, it is preferable that a new top cover for covering the optical fiber coupler on the substrate is newly provided, and a cutout groove in which a filter can be inserted only into the optical fiber coupler is provided in the optical fiber coupler. A filter can be implanted in the upper lid so that the filter can be inserted into the cut groove when the upper lid is placed on the substrate.

According to this structure, it is not necessary to inject an adhesive into the cut groove in order to connect the filter to the cut groove, so that the refractive index changes due to deterioration due to the temperature of the material of the adhesive. And the like are eliminated.
In addition, since it is not necessary to form a cut groove in the substrate, cutting can be easily performed and cutting efficiency can be improved.

In this case, it is preferable that the cut grooves are formed so that the interval between the cut grooves is smaller than the thickness of the filter, and the substrate is formed of a flexible material which can be bent.

According to this structure, it is not necessary to inject an adhesive into the cut groove in order to connect the filter to the cut groove, so that the refractive index changes due to deterioration caused by the temperature of the material of the adhesive. And the like are eliminated.
Further, since the substrate provided with the cut grooves is made of a flexible material, when a forcible force is applied to bend the substrate, the cut grooves are expanded so that the filter can be easily inserted into the cut grooves. If the forcible force is released after the filter is inserted into the expanded groove, the filter can be stored exactly in the cut groove without any gap. It is preferable that the filter is stored in the cut groove without any gap, because light loss is reduced.

In practicing the present invention, the input side of the first optical fiber of the optical fiber coupler is used as an input port, the output side is used as an output port, and the input port side of the second optical fiber is used as a drop port. When the light of the first wavelength and the light of the second wavelength propagate to the input port, the light of the second wavelength of the input port propagates from the input port to the output port if there is no filter, In addition, when there is no filter, the light of the first wavelength
An optical fiber coupler is constructed so as to be completely transited and propagated to the optical fiber, and the filter is formed by a plate-type wavelength separation filter that transmits light of the second wavelength and reflects light of the first wavelength. A laser emitting light of a second wavelength for applying an optical signal is connected to an output port of the first optical fiber, and a light receiving means is further provided between the filter and the laser of the first optical fiber. It is good to provide.

According to this structure, the incident light propagating through the first fiber is reflected toward the second fiber in mirror symmetry with respect to a straight line connecting the first point and the second point as an axis. In this manner, an optical element of a filter reflection type wavelength division multiplexing method can be realized by using an optical fiber coupler provided with a filter.

In this case, preferably, the light receiving means is formed by cutting the optical fiber from the side of the first optical fiber so as to reach the inside of the substrate. It is preferable to include a half mirror provided and a light receiving element for receiving light extracted by the half mirror.

In another preferred embodiment of the present invention, the optical fiber coupler is a 3 dB coupler, the input side of the first optical fiber of the optical fiber coupler is an input port, and the output side is an output port. 2, the input port side of the optical fiber is a drop port, and the output port side of the optical fiber is an output port.
When the light of the first and second wavelengths is incident, the light of the first and second wavelengths input to the input port is transmitted to the first and second optical fibers when there is no filter. A 3 dB coupler is configured so that the optical power of the second wavelength is split into two halves and propagates.
A first plate-type wavelength separating filter that transmits light of the second wavelength and reflects light of the first wavelength is provided at an output port of the first optical fiber. A laser emitting light is connected, a light receiving means is connected to an output port of the second optical fiber,
A second plate-type wavelength separation filter traversing the second optical fiber is provided between the filter and the drop port of the second optical fiber, and the first plate-type wavelength separation filter reflects the first plate-type wavelength separation filter. Is provided at an inclination that does not allow the light having the wavelength of not to re-enter the second optical fiber.

According to this structure, it is not necessary to form an oblique cut groove on the substrate, which is necessary for using a half mirror, preferably for inclining at 45 °. Therefore, since all the cut grooves can be engraved perpendicularly to the substrate, when the filter is implanted in the newly provided upper lid and covers the substrate, it is extremely easy to join the upper lid and the substrate. Become.

In this case, preferably, the first wavelength is 1.55 μm, and the second wavelength is 1.31 μm.
Good to be.

Further, according to the method of manufacturing an optical element according to the present invention, the first step of fixing the optical fiber coupler to the substrate and the second step of cutting the optical fiber coupler to provide a cut groove reaching the substrate are provided. And a step.

According to this structure, since the cut groove is provided after the optical fiber coupler is fixed to the substrate, the optical fiber coupler does not shift.

According to another method for manufacturing an optical device according to the present invention, the first step of fixing the optical fiber coupler to the substrate and the second step of providing a cut groove only in the optical fiber coupler are provided.
And a third step of implanting a filter on the joining surface of the upper lid to be bonded to the substrate so as to cover the optical fiber coupler, so that the filter can be inserted into the notch when the upper lid is placed on the substrate.
And a fourth step of joining the upper cover to the substrate and the filter inserted into the cut groove.

According to this structure, it is not necessary to inject an adhesive into the cut groove to connect the filter to the cut groove, so that the refractive index changes due to deterioration due to the temperature of the material of the adhesive. And the like are eliminated.
In addition, since it is not necessary to form a cut groove in the substrate, cutting can be easily performed and cutting efficiency can be improved.

According to another method for manufacturing an optical element according to the present invention, a first step of fixing an optical fiber coupler to a substrate made of a flexible material, and a filter for cutting the optical fiber coupler and reaching the inside of the substrate. A second step of providing a notch groove narrower than the thickness of the optical fiber coupler, and a joining surface of an upper lid for joining to the substrate so as to cover the optical fiber coupler, so that the upper lid can be inserted into the notch groove when the upper lid is put on the substrate. A third step of implanting a filter, a fourth step of applying a forcing force to bend the substrate to expand the cut groove, a fifth step of inserting the filter into the cut groove, and a forcing force applied to the substrate. And a sixth step of bonding the upper lid and the substrate by releasing the upper cover.

According to this structure, it is not necessary to inject an adhesive into the cut groove to connect the filter to the cut groove, so that the refractive index changes due to deterioration caused by the temperature of the material of the adhesive. And the like are eliminated.
Further, since the substrate provided with the cut grooves is made of a flexible material, when a forcible force is applied to bend the substrate, the cut grooves are expanded so that the filter can be easily inserted into the cut grooves. If you remove the force by inserting a filter there,
The filter can be stored exactly in the cut groove without any gap. It is preferable that the filter is stored in the cut groove without any gap, because light loss is reduced.

Further, according to the optical element of the present invention, in an optical element having a filter reflection type wavelength division multiplexing system in which a filter is provided in a four-terminal one-input three-output optical coupler, the filter is a flat-plate type wavelength separation filter; The optical coupler is a light directional coupler having a first light propagation means and a second light propagation means, and a light energy of incident light propagating through the first light propagation means and a second energy due to the incident light. When the positions in the first and second light propagation means at which the light energy of the distributed light generated in the light propagation means is equal to the first point and the second point, respectively, the first and second points Through
The filter is arranged so as to be substantially orthogonal to the upper surface of the substrate.

According to this structure, the incident light propagating through the first light propagation means is mirror-symmetrical about the straight line connecting the first point and the second point toward the second light propagation means. Is reflected. Therefore, the position on the optical fiber where the relative relationship of the energy due to the distributed coupling of the light becomes mirror-symmetric is defined as the first position.
Is used as a point for arranging a filter for reflecting the light propagating through the light propagating means to the second light propagating means. Therefore, an optical directional coupler provided with a filter, which has not been provided in the past, is used. The optical element of the filter reflection type wavelength division multiplexing system can be realized.

In this case, it is preferable that the optical directional coupler be an optical fiber coupler having a first optical fiber and a second optical fiber.

With this configuration, fine adjustment for connecting the optical element and the optical fiber is not required.

In this case, it is preferable that the optical directional coupler is an optical waveguide type optical directional coupler having a first optical waveguide and a second optical waveguide.

With such a configuration, even in the optical directional coupler using the optical waveguide, by disposing the filter at a predetermined position, the optical waveguide type optical directional coupler provided with the filter, which has not been provided in the past, can be obtained. An optical element of a filter reflection type wavelength division multiplex system using a coupler can be realized.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical device according to the present invention will be described below with reference to the drawings. FIGS. 1 to 13 merely schematically show the shapes, sizes and arrangements of the components so that the present invention can be understood.

An optical element for solving the first problem will be described in the first to third embodiments. Next, regarding the optical element for solving the second problem,
This will be described in a fourth embodiment.

[First Embodiment] The structure of an optical device according to a first embodiment of the present invention will be described with reference to FIGS. FIGS. 1A and 1B are a top view showing a main structure of an optical element (ONU) according to a first embodiment of the present invention and FIG. 1A along a first optical fiber 12A. It is sectional drawing which cut. FIG. 2 is a side view for explaining a state of light propagation of the ONU according to the first embodiment of the present invention. FIG. 3A is an explanatory diagram schematically showing a change in the traveling direction of light due to distributed coupling when there is no filter, and FIG. 3B shows a state where light propagates when there is a filter. FIG. FIG. 4 is an explanatory diagram showing a state where light transitions due to distributed coupling in the optical fiber coupler. FIG. 5 is an explanatory diagram showing another state in which light transitions due to distributed coupling in the optical fiber coupler. FIG.
FIG. 4 is an explanatory diagram showing still another state in which light transitions due to distributed coupling in an optical fiber coupler. FIG. 7 is a diagram showing a procedure for manufacturing the optical device according to the present invention.

In the present invention, an ONU, that is, an optical element of a filter reflection type wavelength division multiplex system in which a filter is provided in an optical coupler having four terminals and one input and three outputs will be described.

Here, as shown in FIG. 1A, as an optical coupler, an optical fiber having a first optical fiber 12A and a second optical fiber 12B fixed to the upper surface of a substrate 10 made of glass, for example. A coupler 12 is used.
Here, the term “optical fiber coupler” refers to two optical fibers arranged side by side as well known from the description of Document 2 (Opto-Mechanical Materials Manual, pp. 262 to 263, Optronics, issued on June 20, 1997). After that, heating, melting, stretching and the like are performed to couple and branch light in one waveguide structure.

The means for fixing the substrate, for example, the substrate 10 made of glass, to the optical fiber coupler 12 is a transparent epoxy resin. For example, here, as shown in FIG. Is molded with the epoxy resin 14 so as to cover. In FIG. 1A,
The illustration of the epoxy resin 14 is omitted.

The substrate, for example, the substrate 10 made of glass is provided with cut grooves 16a and 16b which cut the optical fiber coupler and reach the substrate. Therefore, filters, here, a plate-type wavelength separation filter 18 and a half mirror 20, are arranged in the cut grooves 16a and 16b, respectively. In this example, the cut groove 16a
Are formed perpendicularly to the substrate, for example, the substrate 10 made of glass, and the cut grooves 16b are formed obliquely at 45 ° to the substrate, for example, the substrate 10 made of glass.

The half mirror 20 reflects half of the incident light above the substrate 10 and transmits the remaining light. The light reflected upward is received by a light receiving element, for example, a photodiode (PD) 22 in this case (see FIG. 2).

Further, the laser 24 is connected to the output port 12d.
Is connected, and the laser 24 is
a, and an alignment unit 24b serving as a substrate for coupling the optical fiber and the laser main body 24a. The laser body 24a emits light of the second wavelength, here 1.31.
μm light is oscillated, and this oscillated light is added as an optical signal from the output port 12d to the first optical fiber 12A (AD
D) Yes.

As shown in FIG. 1, the optical fiber coupler 12 has an input port 12a for inputting light of different wavelengths, for example, light of a first wavelength and light of a second wavelength. , For example, a drop port 12b for extracting light of the first wavelength, a coupler unit 12c for binding the first optical fiber 12A and the second optical fiber 12B, and light other than light of a predetermined wavelength. Wavelength of light,
For example, here, it comprises output ports 12d and 12e for extracting light of the second wavelength. Here, the light of the first wavelength, for example, wavelength 1..
Light A having a wavelength of 55 μm and light having a second wavelength, for example, light B having a wavelength of 1.31 μm are input.

Next, the first optical fiber 12A and the second
The position on the optical fiber 12B where the wavelength separation filter 18 is arranged will be described in detail below.

In FIG. 3A, the first optical fiber 1
The light having the first wavelength, for example, light A having a wavelength of 1.55 μm, which is input to 2A, transitions to the second optical fiber 12B by distributed coupling by the second optical fiber 12B, and the first light The light having the second wavelength, for example, light B having a wavelength of 1.31 μm input to the fiber 12A is transmitted from the input port 12a of the first optical fiber 12A to the output port 1A.
The optical fiber coupler 12 is configured such that the distance between the first optical fiber 12A and the second optical fiber 12B is determined so as to propagate to 2d.

Next, as shown in FIG. 3B, light A having a wavelength of, for example, 1.55 μm is reflected, and for example, light having a wavelength of 1.31 μm is reflected.
A plate-type wavelength separation filter 18 that transmits m light B is placed at a predetermined position of the first optical fiber 12A and the second optical fiber 12B, which will be described later, for example, a substrate 10 made of glass.
Vertically. Then, as shown in FIG. 3B, the lights A and B of both wavelengths preferably enter the filter 18 preferably vertically, and then only the light A having a wavelength of 1.55 μm is reflected as shown in FIG. The light propagates to the drop port 12b of the second optical fiber 12B. On the other hand, the light B having a wavelength of 1.31 μm is applied to a flat-type wavelength separation filter 18 as shown in FIG.
Through the output port 12d of the first optical fiber 12A.
Propagate to

Here, how to select the position where the plate-type wavelength separation filter 18 is disposed on the first and second optical fibers 12A and 12B will be described with reference to FIGS. 4 to 6 by taking a light propagation pattern as an example. .

The optical fiber coupler has three types of light propagation patterns. First, as shown in FIG. 4, it is conceivable that the incident light A1 propagates from the input port 12a and the distributed light A2 propagates to the output port 12e. This is defined as a first pattern.

FIG. 4 is a diagram showing the progress of light propagation in a time series for the first pattern.

In FIG. 4, light A1 having a first wavelength is input to an input port 12a of a first optical fiber 12A. D1 of the mountain-shaped dotted line shown in the drawing means the optical power at this time, and the height of the mountain indicates the magnitude of the optical power. When the light A1 approaches the second optical fiber 12B,
The optical power D1 of the light A1 is distributed to the second optical fiber 12B due to the distributed coupling, and is distributed as two optical powers to the optical power D2 and the optical power D3 of the distributed light. Then, with the passage of time, the optical power D2 becomes the second
To the optical fiber 12B, the optical power D2
The optical power D3 increases by an amount corresponding to the decrease. Eventually, the optical powers D2 and D3 become two optical powers D4 and D5 having the same optical power. The position on the first optical fiber 12A when the optical powers are equal is referred to as a first point P
The position on the first and second optical fibers 12B is defined as a second point P2. Next, the optical power D4 decreases to the optical power D6, and the optical power D5 increases by the decrease to the optical power D7. Then, the optical power D6 further decreases and becomes almost zero, and the optical power D7 increases by the reduced amount to become the optical power D8. At this time,
Since the distance between the first optical fiber 12A and the second optical fiber 12B increases, the transition of the optical power due to the distributed coupling does not occur any more. That is, the second optical fiber 1
The light is output as light A2 propagating through the output port 12e of 2B.

The first point P1 and the second point P1
The point P2 is caused by the incident light propagating through the first optical fiber 12A, for example, the optical power of the light A1 having a wavelength of 1.55 μm and the incident light A1, that is, due to the distributed coupling of the incident light. Therefore, the first and second optical powers of the distributed light A2 generated in the second optical fiber 12B become equal.
Of the optical fibers 12A and 12B are shown.

Then, through these first and second points P1 and P2, a substrate, for example, a substrate 1 made of glass
The filter is arranged so as to be substantially orthogonal to the upper surface of the zero.
Note that the first point P1 is a position where the optical power is reduced by -3 dB if the loss of light due to the optical fiber is ignored.

Here, a flat plate is preferable as the filter in order to reflect two lights which are distributed and coupled, and a flat plate type wavelength separation filter is used here.

FIG. 5 shows the second pattern. FIG.
5 shows a so-called 3 dB coupler that outputs the light A1 incident on the input port 12a of FIG. 5 as two lights having the same optical power as the output ports 12e and 12d.

In FIG. 5, the optical power E1 of the light A1 incident on the input port 12a is the second optical fiber 12B.
, Distributed light is excited on the second optical fiber 12B by distributed coupling. Assuming that the light power of the distributed light is E3, this light power E3 is equal to the light power E1.
Becomes almost equal to the amount of decrease in the optical power when the optical power decreases to the optical power E2 due to the distributed coupling. And
The optical power E3 increases as the optical power E2 decreases, and eventually the two optical powers become equal to become the optical power E4 and the optical power E5. The position on the first optical fiber 12A when the two optical powers are equal is referred to as a first point P
1. Further, the point on the second optical fiber 12B is
Is defined as point P2. Here, since the distance between the first optical fiber 12A and the second optical fiber 12B is enlarged, the transition of the optical power due to the distributed coupling does not occur from here. Therefore, the two optical powers E4 and E5 are the light A1 and the optical power E7 of the optical power E6 having the same optical power.
And propagates to the output port 12e of the first optical fiber 12A and the output port 12d of the second optical fiber 12B. Also in this case, similarly to FIG. 4, the first point P1 and the second point P2
Are determined as one each.

The manner of arranging the filter includes the first point P1 and the second point P2 as in the case of FIG. 4, and is perpendicular to the substrate, for example, the substrate 10 made of glass. So that the filters are arranged.

FIG. 6 shows a third pattern. The third pattern shown in FIG. 6 shows a pattern that propagates from the input port 12a to the output port 12d.

As in FIGS. 4 and 5, the incident light A in FIG.
One optical power F1 becomes optical powers F2 and F3 by distributed coupling. The positions of the optical powers E4 and E5 at which the first two optical powers are equal are defined as a first point P1 and a second point P2. Then, the optical power F4 changes almost all the optical power onto the second optical fiber 12B to become the optical power F6. At this time, the optical power on the first optical fiber 12A becomes almost zero. Then
The optical power F6 is distributed to the first optical fiber 1 by distributed coupling.
The distributed light is excited on 2A, and becomes the optical powers F7 and F8 in which the two optical powers become equal for the second time. The positions at which the two optical powers become equal in the second time are defined as a third point P3 and a fourth point P4. Next, the optical power E8 transits onto the first optical fiber 12A,
The optical power decreases to F10. On the other hand, the optical power F7 increases by the decrease of the optical power to become the optical power F9. Further, the transition of the optical power proceeds, and the optical power F10
, Almost all optical power transitions on the first optical fiber 12A and becomes almost zero. Therefore, the light A1 of the optical power F11
And output to the output port 12d.

In this case, unlike FIGS. 4 and 5, third and fourth points P3 and P4 having the same state except for the points P1 and P2 are formed. First and second points P1, P2 and third and fourth points P3, P
In both cases, a similar result can be obtained by disposing a filter. However, considering the loss of light and the like, it is better to set the first point where the optical power of the incident light and the optical power of the distributed light are first equal to the first point P1 and the second point P2. This is preferable because less reflected light can be obtained. Note that the manner of arranging the filters is the same as the first pattern and the second pattern, and thus will not be described here.

With this configuration, the incident light propagating through the first optical fiber 12A is mirror-symmetrical about the straight line connecting the first point P1 and the second point P2 to the second optical fiber 12B. It is reflected toward. Therefore, it is possible to realize a filter reflection type wavelength division multiplexing type optical element by using the optical directional coupler provided with the filter, here, the optical fiber coupler 12 provided with the filter.
As a result, the alignment between the optical fiber and the optical element is ultimately performed at only one position between the output port 12d of the first optical fiber 12A and the laser 24, so that the alignment work is reduced. In addition, the precision required for the alignment between the optical fiber and the optical waveguide must be 0.2 dB or less, whereas the alignment between the optical fiber and the laser may be 1 dB or less. Therefore, it is much easier to align the optical fiber with the laser.

The above-described method of selecting the position at which the filter is arranged is similarly applied to the second embodiment.

Next, a method of manufacturing the optical device will be described.

As shown in FIG. 7, the method of manufacturing an optical device according to the present invention goes through the following process.

First, a desired optical fiber coupler 12 is produced on its own or an off-the-shelf product suitable for the purpose is prepared (block A). Then, the optical fiber coupler 12 is connected as shown in FIG.
As shown in (B), for example, a first step (block B) of fixing to a substrate, for example, a substrate 10 made of glass, so as to cover the entire optical fiber coupler 12 with an epoxy resin 14, The optical fiber coupler 12 in the first step is formed by, for example, dicing cutting.
Cut grooves 16a and 16b that cut into substrate 10
The main part of the present invention is completed through a second step (block C) of providing Then, the cut grooves 16a, 16b
The wavelength separation filter 18 and the half mirror 20 are inserted into the block (block D). Next, a light receiving element, here, a photodiode (PD) 22 is arranged at a position where the reflected light from the half mirror 20 can be appropriately received (block E). Finally, the output port 12 of the first optical fiber 12A
A laser, that is, a laser diode (LD) 24 is connected to d to complete the process (block E). If you do this,
Since the cut groove is provided after the optical fiber coupler 12 is fixed to the substrate, for example, the substrate 10 made of glass, the optical fiber coupler 12 does not shift, and the connection between the optical element and the optical fiber is not changed as in the related art. No need for cumbersome positioning work.

[Second Embodiment] A second embodiment of the present invention will be described below with reference to FIGS.

FIG. 8 is a schematic structural view for explaining a second embodiment of the optical element of the present invention. FIG. 9 (A)
FIG. 9B is an explanatory diagram schematically showing a change in the traveling direction of light due to distributed coupling when there is no filter, and FIG. 9B is an explanatory diagram showing a state where light propagates when there is a filter.

In FIG. 8, the optical fiber coupler 30
It is a dB coupler. The input side of the first optical fiber 30A of the optical fiber coupler 30 is an input port 30a, and the output side is an output port 30d. At the same time, the input port side of the second optical fiber is the drop port 30b, the output port side of the second optical fiber 30B is the output port 30e, and the first optical fiber 30A and the second optical fiber
The coupler unit for binding 0B is 30c.

The input port 30a of the coupler 30 has
Consider a case in which light having the first and second wavelengths, for example, light having a wavelength of 1.55 μm and light having a wavelength of 1.31 μm are incident. Light of the first and second wavelengths input to the input port 30a, for example, light A of wavelength 1.55 μm and wavelength 1.
The light B of 31 μm is shown in FIG.
As shown in (A), the first and second optical fibers 30
A 3 dB coupler is formed in each of A and 30B so that the optical powers of the light A and B of the first and second wavelengths are respectively split and propagated in half. And the filter 32
As shown in FIG. 9B, after light A and B having the first and second wavelengths are vertically incident, light having the second wavelength, for example, light B having a wavelength of 1.31 μm is transmitted here. Together with light of the first wavelength, for example, 1.55 μm
Is a first plate-type wavelength separation filter 32 that reflects the light A.

Further, as shown in FIG. 8, a laser 24 which emits light of a second wavelength for applying an optical signal, for example, light B of a wavelength of 1.31 μm, is provided at an output port 30d of the first optical fiber 30A. Is connected. The light receiving means 22 is connected to the output port 30e of the second optical fiber 30B.

Further, as shown in FIG. 8, light of the second wavelength, for example, light B having a wavelength of 1.31 μm, is reflected on the side of the drop port 30b around the filter 32 of the second optical fiber 30B. At the same time, there is provided a second plate-type wavelength separation filter 34 that transmits light of a first wavelength, for example, light A having a wavelength of 1.55 μm. This second
The plate-type separation filter 34 of the laser 24 is preferably
Light having a second wavelength, e.g., 1.31 μm
It is preferable to provide the light B with a gradient such that the light B does not enter the second optical fiber 30B. For example, a gradient of about 5 ° is provided between the vertical line of the second plate-type separation filter 34 and the second optical fiber 30B (see FIG. 8).

The first plate-type wavelength separation filter 32
Is provided in a cut groove 36a cut in a direction perpendicular to the substrate, for example, the substrate 10A made of glass. Also,
The second plate-type wavelength separation filter 34 is provided in a cut groove 36b cut in a direction perpendicular to the substrate, for example, the substrate 10A made of glass. These grooves 36a and 3
6b is formed by, for example, dicing cutting. The selection of the position where the first plate-type wavelength separation filter 32 is arranged is performed in the same manner as in the case of the plate-type wavelength separation filter 18 in the first embodiment.

With this configuration, as shown in FIG. 1B, the substrate 10A required when the half mirror 20 is installed
The oblique cut groove 16b for inclining the half mirror 20 at an angle of 45 ° is not required to be formed on the substrate 10. Therefore, with the configuration shown in FIG. 8, all the cut grooves 36a and 36b can be formed vertically in the substrate, for example, the substrate 10A made of glass. Therefore, a case will be considered in which filters 32 and 34 are implanted in a newly provided upper lid 40 described later and cover the substrate 10A. The filters 32 and 34 are implanted perpendicular to the substrate 10A. Therefore, the upper lid 4
0 is kept horizontal to the upper surface of the substrate 10A, and the filter 32
1 and 34 can be easily joined by vertically moving them so as to be inserted into the cut grooves 36a and 36b (FIG. 1).
0).

[Third Embodiment] As a modified example of the first and second embodiments described above, the following case is also conceivable.

FIG. 10 is a view showing a third embodiment using an upper lid in the above-described second embodiment, and is a cross-sectional view taken along the second optical fiber 30B.

FIG. 11 is a cross-sectional view of the ONU cut along the optical fiber 30B, in which a cut groove is provided only in the optical fiber coupler.

FIGS. 12A, 12B and 12C are views showing a process of inserting a filter into a cut groove when a substrate made of a flexible material is used.

As shown in FIG. 10, an upper cover 40 for covering the optical fiber coupler 30 on the substrate 10B is newly provided on a substrate having substantially the same structure as that of the second embodiment, for example, a substrate 10B made of glass. Provide. And the top lid 4
0 is placed on the substrate 10B and the cut grooves 36a and 3
Filters, for example, first and second plate-type wavelength separation filters 32 and 34 may be implanted in the cut grooves 42a and 42b provided in the upper lid 40 so that they can be correctly inserted into the upper cover 6b.

With such a configuration, the cut groove 36a
And 36b, it is necessary to inject an adhesive, for example, a silicone-based UV-curable adhesive or an acrylate-based UV-curable adhesive into the cut grooves to connect filters, for example, the first and second plate-type wavelength separation filters 32 and 34. Disappears. Therefore, the light transmitted through the adhesive fixed to the filters 32 and 34, for example, the silicone-based UV-curable adhesive or the acrylate-based UV-curable adhesive, changes the refractive index of the filter due to deterioration caused by the temperature of the material of the adhesive. Inconveniences such as performing are eliminated.

In this case, as shown in FIG. 11, an upper cover 40 for covering the optical fiber coupler 30 on the substrate 10C is newly provided. Next, cut grooves 36c and 36d into which the filters 32 and 34 can be inserted only into the optical fiber coupler 30 are formed by, for example, dicing. The filters 32 and 34 can be implanted in the cut grooves 42a and 42b provided in the upper cover 40 so that the filters 32 and 34 can be inserted into the cut grooves 36c and 36d when the upper cover 40 is put on the substrate 10C.

According to this structure, the cut groove 36c is formed.
There is no need to inject an adhesive, for example, a silicone-based UV-curable adhesive or an acrylate-based UV-curable adhesive into the cut grooves 36c and 36d to connect the filters 32 and 34 to the filters 32 and 34. for that reason,
Problems such as a change in the refractive index due to deterioration caused by the temperature of the material of the adhesive and the like are eliminated. Further, since it is not necessary to form a notch groove in the substrate 10C, cutting,
For example, dicing cutting is easy and the efficiency of the cutting operation can be improved.

In this case, as shown in FIG. 12, the gap between the grooves is preferably smaller than the thickness of the filters 32 and 34, and the substrate 10D is made of a flexible material such as rubber. May be.

With this structure, the cut groove 36e
And 36f, it is not necessary to inject an adhesive, for example, a silicone-based UV-curable adhesive or an acrylate-based UV-curable adhesive into the cut groove to connect the filters 32 and 34 to the substrate 10C made of, for example, glass. Therefore, problems such as a change in the refractive index due to deterioration of the material of the adhesive, for example, the silicone-based UV-curable adhesive or the acrylate-based UV-curable adhesive S due to the temperature or the like are eliminated. In addition, since the substrate provided with the cut grooves is made of a flexible material, for example, rubber or the like, a forcing force is applied to bend the substrate. Then, the cut grooves 36e and 36f are expanded so that the filters 32 and 34 can be easily inserted into the cut grooves 36e and 36f. An adhesive, for example, a silicone-based UV-curable adhesive or an acrylate-based UV-curable adhesive S is added thereto, and the filters 32 and 34 are inserted to release the forcible force.
Then, the filters 32 and 34 can be exactly stored in the cut grooves 32 and 34 without any gap. In this way, the filters 32 and 34 are
It is preferable that the housings 6e and 36f be housed without any gap, because the loss of light is reduced.

In this case, as shown in FIG. 11, the method for manufacturing the optical element of the present invention when the upper lid 40 is used is the same as that described in the first embodiment. Is fixed to the substrate 10C so as to cover the entire optical fiber coupler 30 with, for example, the epoxy resin 14 (first step). Next, only the optical fiber coupler 30 in the first step is provided with the cut grooves 36c and 36d by, for example, dicing (second step). Further, the substrate 1 is so covered as to cover the optical fiber coupler 30.
The upper cover 40 to be joined to the upper cover 40 is prepared, and the filter 32 is inserted into the cut surfaces 36c and 36d so that the upper cover 40 can be inserted into the cut grooves 36c and 36d when the upper cover 40 is put on the substrate 10c.
And 34 are inserted (third step). The filter 3
Nos. 2 and 34 are inserted into the cut grooves 36c and 36d to which an adhesive, for example, a silicone-based UV-curable adhesive or an acrylate-based UV-curable adhesive S is added, and are fixed by irradiating ultraviolet rays. Next, the upper lid 40 is
In the step, only the optical fiber coupler is bonded to the substrate provided with the cut groove (fourth step).

With this structure, the cut groove 36c is formed.
And 36d, there is no need to inject an adhesive, such as a silicone-based UV-curable adhesive or an acrylate-based UV-curable adhesive, into the cut grooves to connect filters, for example, the plate-type wavelength separation filters 32 and 34. Inconveniences such as a change in the refractive index due to alteration due to the temperature or the like of the material are eliminated. The substrate 10
Since it is not necessary to form a cut groove in C, cutting work, for example, dicing cutting work is easy, and the efficiency of cutting work can be improved.

Further, when the upper lid 40 is used, the optical element of the present invention may be manufactured by the following steps.

That is, as shown in FIG. 12, the optical fiber coupler 30 is fixed to the substrate 10D made of a flexible material (first step). Next, cut grooves 36e and 36f, which are narrower than the thicknesses of the filters, for example, the plate-type wavelength separation filters 32 and 34, which reach the substrate 10D by cutting the optical fiber coupler 30 in the first step, are cut by, for example, dicing. (Second step). In addition, a filter such as a plate-type wavelength filter is provided so that the upper cover 40 can be inserted into the cut grooves 36e and 36f when the upper cover 40 is placed on the substrate 10D so as to be bonded to the substrate 10D so as to cover the optical fiber coupler 30. The separation filters 32 and 34 are implanted (third step). Next, a forced force for bending the substrate 10D is applied to expand the cut groove (fourth step). Next, filters, for example, the plate-type wavelength separation filters 32 and 34 are cut into the cut grooves 36 e and 3.
6f (fifth step). Then, the forcible force applied to the substrate 10D is released, and the upper lid 40 and the substrate 10D are joined (sixth step).

With such a configuration, the cut groove 36e
And 36f, there is no need to inject an adhesive, for example, a silicone-based UV-curable adhesive or an acrylate-based UV-curable adhesive into the cut grooves 36e and 36f to connect the filters, for example, the plate-type wavelength separation filters 32 and 34. Therefore, problems such as a change in the refractive index due to deterioration due to the temperature or the like of the material of the adhesive are eliminated. In addition, the substrate 10D provided with the cut grooves is:
It is made of a flexible material such as rubber. Therefore, the substrate 10D
When a forcing force is applied so as to bend the slits 3, the filters, for example, the plate-type wavelength separation filters 32 and 34 are easily inserted into the slits 36 e and 36 f.
6e and 36f expand. When the filters, for example, the plate-type wavelength separation filters 32 and 34 are inserted therein and the forcible force is released, the filters, for example, the plate-type wavelength separation filters 32 and 34 are housed exactly in the cut grooves 36e and 36f without any gap. be able to. Thus, it is preferable that the filters, for example, the plate-type wavelength separation filters 32 and 34 are housed in the cut grooves 36e and 36f without any gap, because the loss of light is reduced.

[Fourth Embodiment] Next, an optical device for solving the second problem will be described.

FIG. 13 is a schematic configuration diagram showing the fourth embodiment. More specifically, FIG. 1 shows an optical coupler of a four-terminal, one-input, three-output type, in this case, the first of a filter reflection type wavelength division multiplexing type optical element in which a filter is provided in an optical directional coupler 50.
Is a cross-sectional view taken along the optical waveguide 50A.
The filters are plate-type wavelength separation filters 18 and 20. The optical directional coupler 50 includes a first light propagation unit, preferably a first optical waveguide 50A and a second light propagation unit, for example, a second optical waveguide 50B.
The first optical waveguide 50A and the second optical waveguide 50
B is formed on the upper surface of the substrate 10E by an ion implantation method.
Further, the upper surface of the substrate 10E is covered with silicon dioxide (SiO 2).
₂ ) Cover with 14A.

Further, the optical power of the incident light propagating through the first optical propagation means, for example, the first optical waveguide 50A, and the second light propagation means, for example, the second optical waveguide 50, due to the incident light.
The position of the first and second light propagation means, for example, the first and second optical waveguides 50A and 50B, at which the optical power of the distributed light generated at B becomes equal to the first point P1 and the second point, respectively. P2 (see FIGS. 4, 5, and 6).
Then, the filter passes through the first and second points P1 and P2 and is substantially orthogonal to the upper surface of the substrate 10E.
For example, a plate-type wavelength separation filter 18 is provided.

With this structure, the first light propagating means, for example, the incident light propagating through the first optical waveguide 50A, for example, the light having the first wavelength, here the light A having the wavelength of 1.55 μm,
However, the second light propagating means, for example, the second
Is reflected toward the optical waveguide 50B. Therefore, the positions on the optical waveguides 50A and 50B where the relative relationship of the optical power due to the distributed coupling of the light becomes mirror-symmetrical are defined as the first light propagation means,
For example, it is used as a point for arranging a filter for reflecting light propagating in the first optical waveguide 50A to the second optical propagation means, for example, the second optical waveguide 50B, for example, the plate-type wavelength separation filter 18. . Therefore, it is possible to realize an optical element of a filter reflection type wavelength division multiplexing system using an optical directional coupler provided with a filter, which has not been conventionally provided.

In this case, preferably, the optical directional coupler is an optical waveguide type optical directional coupler having a first optical waveguide and a second optical waveguide.

With this configuration, even in the optical directional coupler using the optical waveguide, by disposing the filter at a predetermined position, the optical waveguide type optical directional coupler provided with the filter, which has not been provided in the past, can be obtained. An optical element of a filter reflection type wavelength division multiplex system using a coupler can be realized.

In this case, the optical directional coupler is connected to the first
If it is limited to the optical fiber coupler having the second optical fiber and the second optical fiber, the optical element is the same as the optical element described in the first and second embodiments.

[0098]

As is apparent from the above description, in order to solve the first problem, according to the optical element of the present invention, the first and second optical couplers are fixed to the upper surface of the substrate. Since it is composed of an optical fiber coupler having an optical fiber, a fiber coupler fixed to the substrate can be applied instead of the optical waveguide formed on the conventional substrate. This eliminates the need for connection.

Further, the light passes through the first and second points where the optical power of the incident light is equal to the optical power of the distributed light generated in the second optical fiber due to the incident light, and is substantially on the upper surface of the substrate. Since the filters are arranged so as to be orthogonal to each other, the incident light propagating through the first fiber is reflected toward the second fiber in mirror symmetry with respect to the straight line connecting the first point and the second point as an axis, An optical element of a filter reflection type wavelength division multiplex system can be realized by using an optical directional coupler provided with a filter.

Further, in order to solve the second problem, in place of the optical fiber coupler provided with a filter fixed to a substrate, which is a feature of the optical device of the present invention, an optical waveguide type light provided with a filter is provided. Since the directional coupler is employed, it is possible to realize a filter reflection type wavelength division multiplexing optical element using an optical waveguide type optical directional coupler provided with a filter, which has not been conventionally provided.

[Brief description of the drawings]

FIGS. 1A and 1B are a top view and a cross-sectional view showing a main structure of an ONU showing a first embodiment of an optical element of the present invention.

FIG. 2 is a side view for explaining a state in which light from an ONU propagates.

FIG. 3A is an explanatory diagram schematically showing a change in a traveling direction of light due to distributed coupling when there is no filter;
(B) is an explanatory view showing a state in which light propagates when there is a filter.

FIG. 4 is an explanatory diagram showing a state in which light transitions due to distributed coupling in the optical fiber coupler.

FIG. 5 is an explanatory diagram showing another state in which light transits due to distributed coupling in the optical fiber coupler.

FIG. 6 is an explanatory diagram showing still another state in which light transitions due to distributed coupling in the optical fiber coupler.

FIG. 7 is a diagram showing a procedure for manufacturing the optical element of the present invention.

FIG. 8 is a schematic configuration diagram for explaining a second embodiment of the optical element of the present invention.

FIG. 9A is an explanatory diagram schematically showing a change in the traveling direction of light due to distributed coupling when there is no filter;
(B) is an explanatory view showing a state in which light propagates when there is a filter.

FIG. 10 is a schematic configuration diagram showing a third embodiment of the optical element of the present invention.

FIG. 11 is a cross-sectional view of an ONU cut along an optical fiber 30B in which a cut groove is provided only in an optical fiber coupler.

FIGS. 12A to 12C are diagrams showing a process of inserting a filter into a cut groove when a substrate made of a flexible material is used.

FIG. 13 is a schematic configuration diagram showing a fourth embodiment of the optical element of the present invention.

[Explanation of symbols]

10, 10A, 10B, 10C, 10E: substrate 12: optical fiber coupler 12a: input port 12b: drop port 12c: coupler section 12d: output port 12e: output port 12A: first optical fiber 12B: second optical fiber 14: Epoxy resin 14A: Silicon dioxide 16a: Cut groove 16b: Cut groove 18: Flat plate wavelength separation filter 20: Half mirror 22: Photodiode 24: Laser 24a: Laser body 24b: Alignment unit 30: Optical fiber coupler 30A: First No. 1 optical fiber 30B: Second optical fiber 30a: Input port 30b: Drop port 30c: Coupler unit 30d: Output port 30e: Output port 32: First plate-type wavelength separation filter 34: Second plate-type wavelength separation Filters 36a, 36b, 6c, 36d, 36e, 36f: Cut groove 40: Upper lid 42a, 42b: Cut groove 50: Optical directional coupler 50a: Input port 50b: Drop port 50c: Output port 50d: Output port 50A: First optical waveguide 50B : Second optical waveguides 52a, 52b: cut grooves A: light having a wavelength of 1.55 μm A1: light propagating on the first optical fiber A2: light propagating on the second optical fiber B: 1.31 μm P1: first point P2: second point P3: third point P4: fourth point D1, D2, D3, D4, D5, D6, D7, D8: optical power E1, E2, E3, E4, E5, E6, E6, E7: Optical power F1, F2, F3, F4, F5, F6, F7, F8, F
9, F10, F11: optical power S: UV curable adhesive

Claims (17)

[Claims] 1. A filter reflection type wavelength division multiplexing type optical element in which a filter is provided in a four-terminal one-input three-output optical coupler, wherein the optical coupler is fixed to an upper surface of a substrate. An optical element comprising an optical fiber coupler having a fiber. 2. The optical element according to claim 1, wherein the filter is a flat-type wavelength separation filter, and an optical power of incident light propagating through the first optical fiber;
The positions on the first and second optical fibers at which the optical power of the distributed light generated in the second optical fiber due to the incident light is equal to the first point and the second point, respectively. Wherein the filter is disposed so as to pass through the first and second points and to be substantially orthogonal to the upper surface of the substrate. 3. The optical element according to claim 1, wherein a position where the optical power of the incident light and the optical power of the distributed light are first equal is defined as the first point and the second point. An optical element characterized by being selected. 4. The optical device according to claim 1, wherein a cut groove reaching the substrate by cutting the optical fiber coupler is provided, and the filter is disposed in the cut groove. An optical element characterized by the above-mentioned. 5. The optical device according to claim 4, further comprising an upper cover newly provided to cover the optical fiber coupler on the substrate, wherein the filter is provided on the upper cover, and the filter is provided when the upper cover is provided on the substrate. An optical element characterized by being implanted so that can be inserted into the cut groove. 6. The optical element according to claim 1, further comprising a new top cover for covering the optical fiber coupler on the substrate, wherein the filter can be inserted only into the optical fiber coupler. An optical element, wherein a groove is provided, and the filter is implanted in the upper lid so that the filter can be inserted into the cut groove when the upper lid is placed on the substrate. 7. The optical element according to claim 5, wherein the cut groove has a groove interval smaller than the thickness of the filter, and the substrate is made of a flexible material that can be bent. Optical element. 8. The optical element according to claim 1, wherein an input side of the first optical fiber of the optical fiber coupler is an input port, an output side is an output port, and the The input port side of the second optical fiber is a drop port. When light of a first wavelength and light of a second wavelength are transmitted to the input port, light of the second wavelength of the input port is transmitted to the input port. Propagates from the input port to the output port when the filter is absent, and the first of the input ports
The optical fiber coupler is configured so that, when the filter is not provided, the light having the wavelength of the first wavelength is completely transited and propagates to the second optical fiber. And a plate-type wavelength separating filter that transmits light and reflects the light of the second wavelength, and a laser that emits light of the second wavelength for applying an optical signal is connected to an output port of the first optical fiber. An optical element, further comprising a light receiving means between the filter of the first optical fiber and the laser. 9. The optical element according to claim 8, wherein the light receiving means cuts the optical fiber from the first optical fiber side and forms an oblique cut formed so as to reach into the substrate. An optical element comprising: a groove; a half mirror provided in the cut groove; and a light receiving element that receives light extracted by the half mirror. 10. The optical device according to claim 1, wherein the optical fiber coupler is a 3 dB coupler, an input side of the first optical fiber of the optical fiber coupler is an input port, and an output side. And an output port, the input port side of the second optical fiber is a drop port, and the output port side of the second optical fiber is an output port, and the input port has first and second ports. When the light having the wavelength of is incident, the light having the first and second wavelengths input to the input port is, when the filter is not provided, the first and the second optical fibers, The 3 dB coupler is configured so that the optical powers of the first and second wavelengths are branched and propagated in half, and the filter transmits the light of the second wavelength. And a first plate-type wavelength separation filter that reflects the light of the first wavelength, and a laser that emits light of a second wavelength for applying an optical signal is connected to an output port of the first optical fiber. A light-receiving means is connected to an output port of the second optical fiber; and a light-receiving means traversing the second optical fiber between the filter and a drop port of the second optical fiber. 2 is provided with a plate-type wavelength separation filter, and the second plate-type wavelength separation filter is tilted so that the light of the second wavelength reflected thereby is not re-entered into the second optical fiber,
An optical element, which is provided. 11. The optical device according to claim 8, wherein the first wavelength is 1.55 μm, and the second wavelength is 1.31 μm. element. 12. An optical element, comprising: a first step of fixing an optical fiber coupler to a substrate; and a second step of cutting the optical fiber coupler to provide a cut groove reaching into the substrate. Production method. 13. A first step of fixing an optical fiber coupler to a substrate, a second step of providing a cutout groove only in the optical fiber coupler, and a joining surface of an upper lid joined to the substrate so as to cover the optical fiber coupler. A third step of implanting a filter so that the upper lid can be inserted into the cut groove when the cover is placed on the substrate; and in a state where the upper lid is inserted into the substrate and the filter is inserted into the cut groove, And a fourth step of bonding. 14. A first step of fixing an optical fiber coupler to a substrate made of a flexible material; and a second step of providing a cut groove having a width smaller than a thickness of a filter in the substrate while cutting the optical fiber coupler. A third step of implanting the filter so that the filter can be inserted into the cutout groove when the upper lid is put on the substrate, on a bonding surface of the upper lid for bonding to the substrate so as to cover the optical fiber coupler. A fourth step of expanding the cut groove by applying a forcing force to bend the substrate, a fifth step of inserting the filter into the cut groove, and releasing the forcing force applied to the substrate. A method for manufacturing an optical element, comprising: a sixth step of joining the upper lid and the substrate. 15. An optical element of a filter reflection type wavelength division multiplex system in which a filter is provided in an optical coupler of four terminals, one input and three outputs, wherein the filter is a plate-type wavelength separation filter, and the optical coupler is a first light propagation. Means and a light directional coupler having a second light propagation means, and an optical power of incident light propagating through the first light propagation means;
The positions in the first and second light propagating means at which the optical power of the distributed light generated in the second light propagating means due to the incident light becomes equal to the first point and the second point, respectively.
Wherein the filter is disposed so as to pass through the first and second points and to be substantially perpendicular to the upper surface of the substrate. 16. The optical device according to claim 15, wherein
An optical element, wherein the optical directional coupler is an optical fiber coupler having a first optical fiber and a second optical fiber. 17. The optical device according to claim 15, wherein
An optical element, wherein the optical directional coupler is an optical waveguide type optical directional coupler having a first optical waveguide and a second optical waveguide.