JPH08234028A - Splitter with wavelength selection function - Google Patents

Abstract

PURPOSE: To provide a splitter with a wavelength selection function capable of inputting and outputting signal light of a prescribed wavelength and signal light branched to different wavelengths to and from respective ports with one piece. CONSTITUTION: This 1×N splitter is formed by using Y branching devices 23a composed of channel waveguides of single mode on a substrate 20 and connecting the input ports 23b, 23c of the plural Y branching devices 23a to the output ports 23ab, 23ac thereof. Asymmetrical directional couplers with gratings having asymmetrical directional couplers consisting of two pieces of parallel channel waveguides varying in core widths and gratings formed between the channel waveguides of the asymmetrical directional couplers or near the cores are connected to the respective output ports 22a to 22r of the 1×N splitter. The light rays inputted to the input port 21 of the 1×N splitter are branched and multiplexed and the light rays of the different wavelengths are outputted from the respective output ports 22a to 22r by changing the period of the gratings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a splitter, and more particularly to a splitter having a wavelength selection function.

[0002]

2. Description of the Related Art FIG. 25 shows a PO using a conventional splitter.
It is a conceptual diagram of the maintenance monitoring system of N (Passive Optical Network).

As shown in FIG. 1, 1 × 16 are arranged in the station.
E / O (electro-optical converter) using the star coupler 10,
O / Es (photoelectric converters) arranged in the homes (subscribers) A to H are respectively connected by optical fibers f.
Devices such as a CATV (cable television) and a telephone are connected to the O / E. The voice signal of the telephone is bidirectionally transmitted with a signal light of wavelength 1.3 μm, and the video signal of CATV is unidirectionally transmitted with a signal light of 1.55 μm. As a result, a signal is transmitted between one subscriber and another subscriber through the optical fiber f and the station.

On the other hand, these signal lights (1.3 μm) are used in the maintenance monitoring system during or after installation of this system.
m, 1.55 μm), and a signal light having a wavelength (1.65 μm) different from the above is used.

OTD for monitoring in the station (or remote facility)
R (Optical Time Domain Reflecto-meter, wavelength 1.6)
The optical switch 12 connected to 5 μm) 11 and each output port of the 1 × 16 star coupler 10 connected to E / O are connected to each port of the plurality of optical branching devices 14, respectively. A wavelength selection filter 13 is inserted in each of the optical fibers connected to the subscribers A to H.

The test signal light for monitoring is sent from the station to each of the subscribers A ...
There is no abnormality such as disconnection in the optical fiber f from the station to each of the subscribers A to H by transmitting to the H, reflecting the test signal light only at each of the subscribers A to H, and monitoring by the OTDR 11 of the station. It is designed to monitor whether or not.

[0007]

However, the conventional maintenance monitoring system shown in FIG. 25 requires as many optical branching devices 14 as the number of branches (the number of subscribers). Also, 1
If the x16 star coupler 10 is to be installed from the station to each of the subscribers A to H, it is necessary to extend the optical fiber f to the optical branching device 14 and the optical switch 12, which is a problem in terms of economy. In this way, the flexibility of the system is significantly reduced.

Therefore, an object of the present invention is to solve the above problems and provide a splitter with a wavelength selection function that can input and output a single signal light of a predetermined wavelength band and test light demultiplexed to different wavelengths. Especially.

[0009]

In order to achieve the above object, the present invention provides a single mode channel waveguide in which a core having a rectangular cross section is embedded in a clad having a refractive index smaller than that of the core on a substrate. Using a Y-shaped Y-brancher, in which one channel waveguide configured in 1 is branched into two waveguides from the middle, the input ports of a plurality of Y-branchers are connected to each other in the two output ports. In the 1 × N splitter described above, an asymmetric directional coupler composed of two parallel channel waveguides having different core widths, and a grating formed between the channel waveguides of the asymmetric directional coupler or in the vicinity of the core are provided. By connecting an asymmetric directional coupler with a grating to each output port of a 1 × N splitter, and changing the period of the grating, a 1 × N
The light input to the input port of the splitter is split and demultiplexed to output light of different wavelengths from each output port.

The present invention comprises a single mode channel waveguide in which a core having a rectangular cross section is embedded on a substrate by a clad having a refractive index smaller than that of the core, and a branching ratio is substantially constant with respect to wavelength. In a 2 × N splitter in which a certain wavelength-independent 2 × 2 coupler and a Y-shaped Y-branching device in which one waveguide is branched into two waveguides from the middle are connected to each other, the core widths are different. An asymmetric directional coupler with a grating comprising an asymmetric directional coupler formed of two parallel channel waveguides and a grating formed between the channel waveguides of the asymmetric directional coupler or in the vicinity of the core is provided. By connecting to each output port of the × N splitter and changing the grating period, the light input to the 2 × N input port is split and demultiplexed to output light of different wavelengths from each output port. In which was to so that.

In addition to the above structure, in the present invention, a coupler having a structure in which two cores having different core widths are crossed may be used as the wavelength independent coupler.

In addition to the above-mentioned structure, the present invention has a wavelength-independent coupler having an adiabatic structure in which two cores having different core widths in a coupling portion are tapered to have gradually equal widths, and the cores are parallel to each other. You may use the coupler comprised by arrange | positioning.

In addition to the above structure, the present invention uses a Mach-Zehnder type wavelength independent coupler composed of two directional couplers and two channel waveguides having different lengths for connecting them as a wavelength independent coupler. May be.

In addition to the above configuration, the height or width of the core may be periodically changed as the grating of the splitter with wavelength selection function of the present invention.

In addition to the above structure, Si ₃ N _{4 is} used as the material of the grating of the splitter with wavelength selection function of the present invention,
Si or TiO ₂ may be used.

[0016]

According to the above construction, the light incident on the input port of the splitter with wavelength selection function is branched into a number N of output ports by a plurality of Y branching units, and the channel waveguides of the asymmetric directional coupler with grating are respectively branched. Incident on. In each asymmetric directional coupler with a grating, when the light incident on the channel waveguide is diffused from the core toward the other channel waveguide, it is diffracted by the grating and only the light of the wavelength corresponding to the period of the grating is It reaches the channel waveguide and is output from the output port. That is, when light in the wavelength band existing in the input port is input, the light is split into the number N of output ports, and is split by each asymmetric directional coupler with grating to output light of different wavelengths.

[0017]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram of a splitter with a wavelength selection function of the present invention.

At one end of the substrate (eg, SiO ₂ ) 20,
An input port 21 for inputting signal light of a certain wavelength band and test lights of a plurality of different wavelengths is formed. A linear waveguide 23aa as an input port of the Y branching device 23a is connected to the input port 21. Y branch 2
The straight waveguide 23ba of the Y branch device 23b is connected to the branch waveguide 23ab as one output port of 3a, and
Branch waveguide 2 as the other output port of the branch 23a
The linear waveguides 23ca of the Y branch device 23c are connected to 3ac, respectively. The straight waveguides of the Y branch devices 23d and 23e are connected to the branch waveguides of the Y branch device 23b, and the straight waveguides of the Y branch devices 23f and 23g are connected to the branch waveguide of the Y branch device 23c. .

Similarly, the straight waveguides of the Y branch devices 23h and 23i are connected to the branch waveguides of the Y branch device 23d, and the straight waveguides of the Y branch devices 23j and 23k are connected to the branch waveguide of the Y branch device 23e. , And the linear waveguides of the Y branch devices 23m and 23n are connected to the branch waveguide of the Y branch device 23f.
Y branching devices 23p and 23q are provided in the branching waveguide of the branching device 23g.
Are connected to each other.

Further, Y branching devices 23h, 23i, 23j,
Each of the branch waveguides 23k, 23m, 23n, 23p, and 23q is a channel waveguide and is connected to the asymmetric directional couplers 24a to 24r with a grating. Each asymmetrical directional coupler 24a-24r has an output port 22a-
A splitter 71 with a wavelength selection function is configured by being connected to 22r.

FIG. 2 is an enlarged view of the Y branch device shown in FIG.

The Y-branching device 23 is connected to the linear waveguide 31, the tapered waveguide 32 connected to the linear waveguide 31, and the tapered waveguide 32, and the core width is gradually changed and has a constant curvature. Substantially S-shaped branch waveguides 33a, 33
b and a slit 34 formed between the connecting portions of both the branched waveguides 33a and 33b. A specific example of the Y branch device 23 is “Silica Waveguide-Type 2
× 16 Splitter with Low Insertion Loss and Small Los
s-Deviation Branches, T.Hakuta, et al, 14C2-3, OEC'9
4 ”. A low loss 1 × 16 splitter can be realized by using the Y branching device in this report example.

FIG. 3 is a diagram showing the configuration of the asymmetric directional coupler with a grating shown in FIG.

Asymmetric directional coupler 2 with grating
4 is a three element waveguide grating 51, 52, 53
And a waveguide 5 for connecting each element waveguide grating
5, 56, 57.

As shown in FIGS. 4 to 6, the element waveguide grating 51 includes an asymmetric directional coupler 40 composed of two channel waveguides 41 and 42 arranged in parallel and having different core widths, and both channel waveguides. A grating 43 is formed between the waveguides 41, 42 in an irregular shape in the longitudinal direction at a substantially constant period.
And a clad 44 that covers them.
4 is a plan view of the element waveguide grating, FIG. 5 is a sectional view taken along the line II of FIG. 4, and FIG. 6 is a sectional view taken along the line II-II of FIG.

The narrower channel waveguide 42 of the asymmetric directional coupler 40 has an adiabatic structure in which the core width gradually increases in a tapered shape. In the asymmetric directional coupler 40, even mode light and odd mode light as shown in the figure propagate. Consider a case where light of wavelength λ is incident on the port Pb. In this case, the odd-mode light is mainly excited, and the even-mode light is hardly excited. If the grating 43 is not provided, the odd-mode light propagates independently of the even-mode light without propagating, and outputs from the port Pd.

However, when the grating 43 is added to the asymmetric directional coupler 40, the even mode light is coupled to the odd mode light according to the period Λ thereof, and when it propagates for a certain length, it becomes completely odd. The light is converted into mode light and is output from any of the ports Pa, Pb, Pc, and Pd.

The conditions will be described below.

(1) When outputting from the port Pa, Λ = λ
/ (Neff + Neffa) (2) When output from the port Pb, Λ = λ / (2Nef
f) (3) When output from the port Pc, Λ = λ / (Neff
a-Neff) (4) When output from the port Pd, Λ has the above (1) to
In cases other than (3), Neff is the equivalent refractive index of the odd mode of the asymmetric directional coupler 40, and Neffa is the equivalent refractive index of the even mode of the asymmetric directional coupler 40.

Generally, quartz glass Neff, Neff
a is 1.460 and 1.465, respectively. Therefore, in the cases of (1) and (2), the period Λ becomes a fraction of the light wavelength, and a considerably small period is required.

On the other hand, in the case of (3), (Neffa-Ne
Since ff) is a small value, the period Λ has a relatively large value of about several tens to several hundreds of the light wavelength.

As described above, the directional coupler 40 changes the period Λ of the grating 43 so that light of a specific wavelength can be output from the four ports Pa, Pb, Pc and Pd separately. it can.

FIG. 7 shows an example of wavelength loss characteristics of the element waveguide grating.

In the figure, the horizontal axis represents wavelength and the vertical axis represents loss (arbitrary scale). The characteristic shown in the figure shows the case of (1) described above, and when light is incident from the port Pb, only light of a certain specific wavelength (1651 nm in this case) is emitted from the port Pa with low loss.

FIG. 8 is a plan view of the element waveguide grating 52 shown in FIG. The element waveguide grating 52 includes a channel waveguide 41 having different core widths.
The period of the grating 43a formed in the asymmetrical directional coupler 40a composed of a and 42a is gradually changed (chirped) so that the interval becomes wider as it gets closer to both ends. Such an element waveguide grating 52 can widen the wavelength bandwidth of reflected light as shown in FIG. FIG. 9 is a diagram showing the characteristics of the element waveguide grating shown in FIG. 8, in which the horizontal axis represents wavelength and the vertical axis represents loss.

Using this principle, the function of the asymmetric directional coupler with a grating will be described with reference to FIG. 3 again. A case where light is incident on the port PB will be described.
The element waveguide grating 51 includes the grating 43.
Since the period of a is gradually changing, the test light is 1.
Light in the 65 μm band (for example, 1651 nm to 1666 nm) is reflected to the port PA in the opposite direction.

The element waveguide grating 51 has a substantially constant period, which reflects, for example, only 1651 nm light of the test light in the 1.65 μm band reflected at the port PA and outputs it from the port PC. It is designed to let you.

Next, unlike the other element waveguide gratings 51 and 52, the element waveguide grating 53 has a longer period, and the period also gradually changes. Therefore, the test light of 1.65 μm band (1651
(nm to 1666 nm) is coupled forward and light is emitted from the port PD.

On the other hand, the wavelength of the signal light is 1.3 μm / 1.
The 55 μm band light is output from the port PD without being affected by the element waveguide grating 53 because the period Λ satisfies the condition (4) described above.

Thus, the signal light of 1.3 μm /
Light in the 1.55 μm band and light of one wavelength in the 1.65 μm band which is the test light can be output to the port PD, and the period Λ of the grating can be changed like the element waveguide grating 52. Thus, the wavelength of the test light can be selected.

At each output port of the 1 × 16 splitter with a wavelength selection function in FIG. 1, the period Λ of the grating of each asymmetric directional coupler 24a to 24r with a grating is different for each port 22a to 22r.
As a result, the wavelength of the test light emitted from the output port is different.

FIG. 10 shows a wavelength-selecting function 1 shown in FIG.
An example of a maintenance monitoring system using a x8 splitter is shown.

In the same way as the conventional example shown in FIG. 25, an E / O in the office is used by using a 1 × 8 splitter 71 with a wavelength selection function.
And the O / Es on the subscribers A to H side are connected via optical fibers f and F. Since the 1 × 8 splitter 71 with a wavelength selection function does not affect the wavelengths of the 1.3 μm and 1.55 μm bands, which are the signal light, the voice signal of a telephone or the like is bidirectional using the light of 1.3 μm. The video signal can be transmitted in one direction using 1.55 μm light.

A monitoring OT in a station or in a remote facility for maintenance monitoring during or after installation of this system
By using the DR 11 and the 1.65 μm wavelength tunable laser 72, and further using the optical multiplexer / demultiplexer 73 to connect to the input port 21 of the 1 × 8 splitter 71 with wavelength selection function, the supervisory signal light is sent to each subscriber A to. It is transmitted to H.

In the above, even if one 1 × 8 splitter 71 with a wavelength selection function is installed from the station to each subscriber A to H side, the PON can be realized by one optical fiber F, which is economical. A system with excellent flexibility and flexibility is possible.

On the side of each of the subscribers A to H, by inserting the wavelength selection filter 13 into the optical fiber f as in the conventional case, only the light in the wavelength band of 1.65 μm for monitoring is reflected and monitored by the OTDR 11. By doing so, it is possible to monitor whether or not there is an abnormality such as a break in the optical fibers f and F from the station to each of the subscribers A to H.

The monitoring method will be described below.

With the 1.65 μm wavelength tunable laser 72,
The wavelength is changed from 1651 nm to 1658 nm in steps of 1 nm, and the light is incident on the OTDR 11. 11 and 12 show examples of OTDR waveforms. 11 and 12, the horizontal axis represents the distance and the vertical axis represents the reflected light amount.
The wavelength of the light used for the test is 1651 nm,
It is possible to monitor up to an optical fiber abnormality. FIG.
1 shows a state where the optical fiber is normal, and FIG. 12 shows a state where the optical fiber is broken. Light is attenuated at the disconnection,
The disconnection point can be specified from the distance along the horizontal axis. By changing the wavelength of the wavelength tunable laser 72, the subscriber B,
The subscriber C, ..., The subscriber H and each subscriber can be monitored.

In this embodiment, 1651 nm, 1652 nm, ..., 16 are used as the test lights in the 1.65 μm band for maintenance monitoring.
The wavelength of 16 waves of 1 nm interval of 66 nm is used, but the wavelength interval is not limited to this.

FIG. 13 is a diagram showing another embodiment of the asymmetric directional coupler with a grating used in the splitter with a wavelength selection function of the present invention, and FIG. 14 is a line III- of FIG.
13 is a sectional view taken along the line III, and FIG. 15 is a sectional view taken along the line IV-IV in FIG.

The difference from the asymmetrical directional coupler with a grating shown in FIG. 4 is that the surface of the clad 44b in which the cores 41b and 42b are embedded is etched in an uneven shape. Even in this case, it is possible to demultiplex light having a wavelength according to the grating interval Λi.

FIG. 16 is a diagram showing another embodiment of the asymmetric directional coupler with a grating used in the splitter with a wavelength selection function of the present invention, and FIG. 17 is a line V- of FIG.
FIG. 18 is a sectional view taken along line V-VI of FIG.

The difference from the asymmetric directional coupler with a grating shown in FIG. 4 is that a grating 43c is formed below the channel waveguide 42c. The grating 43c is provided on the channel waveguide 42c, or on the channel waveguide 41c or below the channel waveguide 42c.
It may be formed in the vicinity of c.

FIG. 19 is a diagram showing another embodiment of the asymmetric directional coupler with a grating used in the splitter with wavelength selection function of the present invention, and FIG.
FIG. 21 is a sectional view taken along line VII, and FIG. 21 is a sectional view taken along line VIII-VIII in FIG.

The difference from the asymmetric directional coupler with a grating shown in FIG. 4 is that GeO ₂ is added to the cladding or core.
Is added, and UV (ultraviolet) laser light is applied to this using a two-beam interference method or a mask, and the change in the refractive index is utilized by the photo-sensitive effect.

In addition, a material having a low refractive index in the near infrared such as glass (for example, Si ₃ N ₄ added SiO ₂ or TiO ₂ ) or metal (for example, Si) having a refractive index different from that of the clad is provided on the upper and lower portions of the channel waveguide. May be added periodically, or the core width of the channel waveguide may be changed periodically.

Further, in this embodiment, 1 × is used as a splitter.
16 splitters are used, but not limited to this, 1 × 2, 1 × 4, 1 × 16, 1 × 32, 2 × 2, 2 ×
It may be applied to a 4, 2 × 8, 2 × 16, 2 × 32 splitter or the like.

FIG. 22 is a diagram showing an example of the 2 × 16 splitter. The difference from the 1 × 16 splitter of FIG.
By using a wavelength-independent coupler 80 having a substantially constant branching ratio with respect to wavelength instead of the Y branching device 23a,
The point is that it has two input ports 21a and 21b. The wavelength-independent coupler 80 equally distributes the light input from the input port 21a or 21b to the Y branching devices 23b and 23c without depending on the wavelength, and outputs the Y branching device 23b.
Alternatively, it has a function of equally distributing the light from 23c to the input ports 21a and 21b without depending on the wavelength. The wavelength-independent coupler 80 shown in the same figure is a Mach-Zehnder type wavelength-less coupler composed of two directional couplers 81a and 81b and two channel waveguides (cores) 82a and 82b connecting the directional couplers 81a and 81b with different lengths. It is a dependent coupler.

23 and 24 are modifications of the wavelength-independent coupler shown in FIG.

The wavelength independent coupler shown in FIG. 23 has two channel waveguides (cores) 83a and 8 having different core widths.
3b has a structure intersecting with each other.

The wavelength-independent coupler shown in FIG. 24 has an adiabatic structure in which two channel waveguides (cores) 84a and 84b having different core widths are tapered in the coupling portion 84c to have gradually equal widths. The cores 84a and 84b are arranged in parallel.

Optical fibers corresponding to the optical fiber F shown in FIG. 10 are respectively connected to the two input ports 21a and 21b of the 2 × N splitter described above, and these two optical fibers are installed up to the inside of the station, and one optical fiber is installed. By connecting the optical fiber of No. 1 to the equipment in the station in the same manner as in FIG. 10 and securing the other optical fiber as a standby line, even if the optical fiber of the working line breaks, it can be quickly switched to the standby line. Can be restored. If the broken optical fiber is repaired while the protection line is in use, further accidents can be prepared.

[0064]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) An asymmetric directional coupler composed of two parallel channel waveguides having different core widths, and a grating formed between the channel waveguides of this asymmetric directional coupler or in the vicinity of the core. By connecting the provided asymmetric directional coupler with a grating to each output port of the 1 × N splitter and changing the period of the unevenness of the grating to output light of different wavelengths from each output port, The signal light of a predetermined wavelength and the signal light demultiplexed to different wavelengths can be individually input / output to / from each port.

(2) An asymmetric directional coupler consisting of two parallel channel waveguides having different core widths and a grating formed between the channel waveguides of this asymmetric directional coupler or in the vicinity of the core are provided. By connecting the provided asymmetric directional coupler with a grating to each output port of the 1 × N splitter and changing the period of the unevenness of the grating to output light of different wavelengths from each output port, one Thus, the signal light having a predetermined wavelength and the signal light demultiplexed into different wavelengths can be input / output to / from each port.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a splitter with a wavelength selection function of the present invention.

2 is an enlarged view of the Y branch device shown in FIG. 1. FIG.

3 is a diagram showing a configuration of the asymmetric directional coupler with a grating shown in FIG.

FIG. 4 is a plan view of the element waveguide grating shown in FIG.

5 is a cross-sectional view taken along line I-I of FIG.

6 is a sectional view taken along line II-II of FIG.

FIG. 7 is a diagram showing an example of wavelength loss characteristics of an element waveguide grating.

FIG. 8 is another plan view of the element waveguide grating shown in FIG.

9 is a diagram showing characteristics of the element waveguide grating shown in FIG.

10 is a diagram showing an example of a maintenance monitoring system using the 1 × 8 splitter with a wavelength selection function shown in FIG.

FIG. 11 is a diagram showing a waveform of OTDR when the optical fiber is in a normal state.

FIG. 12: OTDR in the state where the optical fiber is broken
It is a figure showing the waveform of.

FIG. 13 is a diagram showing another embodiment of the asymmetric directional coupler with a grating used in the splitter with a wavelength selection function of the present invention.

14 is a diagram showing a cross-sectional view taken along line III-III in FIG.

15 is a sectional view taken along line IV-IV in FIG.

FIG. 16 is a diagram showing another example of the asymmetric directional coupler with a grating used in the splitter with a wavelength selection function of the present invention.

17 is a sectional view taken along line VV of FIG.

18 is a sectional view taken along line VI-VI of FIG.

FIG. 19 is a diagram showing another embodiment of the asymmetric directional coupler with a grating used in the splitter with a wavelength selection function of the present invention.

20 is a sectional view taken along line VII-VII of FIG.

21 is a sectional view taken along line VIII-VIII of FIG.

FIG. 22 is a diagram showing an example of a 2 × 16 splitter.

FIG. 23 is a modification of the wavelength independent coupler shown in FIG. 22.

FIG. 24 is a modification of the wavelength independent coupler shown in FIG.

FIG. 25 is a conceptual diagram of a conventional PON maintenance monitoring system using a splitter.

[Explanation of symbols]

 20 substrate 21 input port 22a to 22r output port 23a to 23q Y branch device 40 asymmetric directional coupler 41, 42 channel waveguide 43 grating

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoyuki Shirata 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Cable Co., Ltd.

Claims (7)

[Claims] 1. A single channel waveguide comprising a single mode channel waveguide in which a core having a rectangular cross section is embedded in a clad having a refractive index smaller than that of the core on a substrate, and two channel waveguides are provided from the middle thereof. In a 1 × N splitter in which a Y-shaped Y-branch branching into a waveguide is used, and the input ports of a plurality of Y-branches are connected to two output ports of the Y-branch, the two Y-branches having different core widths are used. The asymmetric directional coupler with a grating, which comprises an asymmetric directional coupler composed of parallel channel waveguides and a grating formed between channel waveguides of the asymmetric directional coupler or in the vicinity of the core, By connecting to each output port of the splitter and changing the period of the grating, the light input to the input port of the 1 × N splitter is split and demultiplexed, and each output port is split. A splitter with a wavelength selection function, which is characterized in that light of different wavelengths is output from the optical fiber. 2. A wavelength which is composed of a single-mode channel waveguide in which a core having a rectangular cross section is embedded in a clad having a refractive index smaller than that of the core on a substrate and whose branching ratio is substantially constant with respect to the wavelength. In a 2 × N splitter in which an independent 2 × 2 coupler and a Y-shaped Y-branching device in which one waveguide is branched into two waveguides from the middle are connected to each other, two 2 × N splitters having different core widths are used. The asymmetric directional coupler with a grating comprising an asymmetric directional coupler consisting of parallel channel waveguides and a grating formed between the channel waveguides of the asymmetric directional coupler or in the vicinity of the core, By connecting to each output port of the N-splitter and changing the period of the grating, the light input to the input port of the 2 × N-splitter is split and demultiplexed to output different wavelengths from each output port. Wavelength selecting function splitter, characterized in that so as to output. 3. The wavelength selective splitter according to claim 2, wherein a coupler having a structure in which two cores having different core widths intersect each other is used as the wavelength independent coupler. 4. The wavelength-independent coupler has an adiabatic structure in which two cores having different core widths in a coupling portion are tapered to have gradually equal widths, and the cores are arranged in parallel. The splitter with a wavelength selection function according to claim 2, which uses a coupler. 5. The Mach-Zehnder type wavelength independent coupler comprising two directional couplers and two channel waveguides having different lengths for connecting them, as the wavelength independent coupler. Splitter with wavelength selection function. 6. The splitter with a wavelength selection function according to claim 1, wherein the height or width of the core is periodically changed as the grating. 7. Si ₃ as a material for the grating
Claims 1 to 6 using N ₄ , Si or TiO _2.
A splitter with a wavelength selection function according to any one of 1.