JP2003315570A - Optical wavelength multiplexer/demultiplexer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small optical wavelength multiplexer/demultiplexer which can multiplex or demultiplex light of a narrow wavelength interval in a wide band and which has low loss, excellent mass productivity and a cost reduction effect. <P>SOLUTION: An optical waveguide circuit 13 is formed on a substrate 20. The optical waveguide circuit 13 is formed by connecting a first to the N-th (N is integer ≥2) narrow spacing optical wavelength multiplexing/demultiplexing circuits 8a and 8b to a corresponding light inputting part 9 or light outputting part 10 of a wideband optical wavelength multiplexing/demultiplexing circuit 7 having a plurality of at least either light inputting parts 9 or light outputting parts 10. For example, a first narrow spacing optical wavelength multiplexing/ demultiplexing circuit 8a multiplexes or demultiplexes light of a first set wavelength band, and a second narrow spacing optical wavelength multiplexing/ demultiplexing circuit 8b has a function for multiplexing and demultiplexing light of a second set wavelength band different from the first set wavelength band. The wideband optical wavelength multiplexing/demultiplexing circuit 7 has a function for multiplexing and demultiplexing light of the total wavelength bands including both of the first to the N-th set wavelength bands. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical wavelength multiplexer / demultiplexer used in an optical communication system or the like.

[0002]

BACKGROUND ART With the recent rapid increase in Internet traffic, there is an urgent need to expand the capacity of communication networks, and along with this, wavelength division multiplexing (Wavelength Division).
Multiplexing (WDM)) transmission technology is being actively studied. The wavelength division multiplex transmission technology is in the limelight because it can increase the transmission capacity by the wavelength multiplex because a plurality of optical signals of different wavelengths are multiplexed and transmitted in one optical fiber.

Various optical devices are required to realize a wavelength division multiplexing transmission system having high flexibility and operability. Among them, the optical wavelength multiplexer / demultiplexer is a device for multiplexing a plurality of signal lights having different wavelengths into one optical fiber, or for demultiplexing a plurality of signal lights for each wavelength,
It is one of the optical devices that is indispensable for constructing a wavelength division multiplexing transmission system.

Various forms of the optical wavelength multiplexer / demultiplexer have been studied, but the optical waveguide type optical wavelength multiplexer / demultiplexer is regarded as a favorite because of its excellent mass productivity and designability, and the Mach-Zehnder optical interference. An optical wavelength multiplexer / demultiplexer having a basic configuration of a meter and an arrayed waveguide diffraction grating is known.

As a means for increasing the number of wavelengths to be multiplexed / demultiplexed, a method of dealing with a narrow spacing between wavelength intervals in a specific wavelength band and expanding the wavelength band have been studied.

Currently, the C band (wavelength 1530 nm to 15
70 nm) and L band (wavelength 1570 nm to 1610 n)
A wavelength division multiplex transmission system utilizing both wavelength ranges of m) has been put to practical use. An example of this system is shown in FIG.
FIG. 22 shows an example of the optical wavelength multiplexing / demultiplexing device 100 (100a) provided on the optical transmission side of this system.

As shown in FIGS. 21 and 22, the optical wavelength multiplexer / demultiplexer 100 (100a) on the optical transmission side has a wavelength multiplexer 21a for the C band and a wavelength multiplexer 21b for the L band.
And a band multiplexer 11 for CL band. Wavelength multiplexer 21a for C band and wavelength multiplexer 2 for L band
1b is connected to the corresponding optical input part of the band multiplexer 11 for CL band via the connection optical fiber 19.

Further, as shown in FIG. 21, the signal light sources 14a1 to 14a1 are provided on the optical input side of the C-band wavelength multiplexer 21a.
14an is connected, and the signal light sources 24a1 to 24an are connected to the optical input side of the wavelength multiplexer 21b for the L band.

The signal lights output from the signal light sources 14a1 to 14an are signal lights having different wavelengths in the C band. The signal lights output from the respective signal light sources 14a1 to 14an are combined by the C-band wavelength multiplexer 21a to become wavelength-multiplexed light having a wavelength in the C-band,
Input to the band combiner 11 for the CL band.

The signal lights output from the signal light sources 24a1 to 24an are signal lights having different wavelengths in the L band. The signal lights output from the respective signal light sources 24a1 to 24an are combined by the wavelength combiner 21b for the L band to be wavelength multiplexed light having a wavelength within the L band, and the band combine for the CL band. Input to the container 11.

The CL band band multiplexer 11 multiplexes the wavelength multiplexed light having a wavelength in the C band and the wavelength multiplexed light having a wavelength in the L band to reach from the C band to the L band. The wavelength-multiplexed light having a wavelength within the wavelength range is input to the optical fiber 16. 22 shows the wavelength λ of the C band.
Lights 1, λ2, λ3, λ4, and λ5 are combined by the wavelength combiner 21a, and the wavelengths λ6, λ7, λ8, and λ of the L band are combined.
An example is shown in which light of wavelengths 9 and λ10 is multiplexed by the wavelength multiplexer 21a, but the wavelength of each light is set appropriately.

The optical fiber 16 is an optical fiber forming an optical transmission line, and the wavelength multiplexed light having a wavelength within the wavelength range from the C band to the L band is amplified by an optical repeater 18 formed by an optical amplifier. Optical fiber 1
Propagate through 6.

The wavelength multiplexed light propagated through the optical fiber 16 is
The optical wavelength multiplexer / demultiplexer 100 (10 provided on the light receiving side)
0b). This optical wavelength multiplexer / demultiplexer device 100 (1
00b) connects the wavelength demultiplexer 22a for C band and the wavelength demultiplexer 22b for L band to the optical output side of the band demultiplexer 12 for CL band via the connecting optical fiber 19. Is formed.

The wavelength-division multiplexed light having a wavelength within the wavelength range from the C band to the L band, which has propagated through the optical fiber 16, is converted into a wavelength within the C band by the band demultiplexer 12 for the CL band. It is demultiplexed into the wavelength-multiplexed light having the wavelength and the wavelength-multiplexed light having the wavelength in the L band.

After that, the wavelength division multiplexed light having a wavelength in the C band is demultiplexed into each signal light by the wavelength demultiplexer 22a for the C band and received by the optical receivers 17a1 to 17an. The wavelength division multiplexed light having a wavelength in the L band is demultiplexed into each signal light by the wavelength demultiplexer 22b for the L band and received by the optical receivers 27a1 to 27an.

The wavelength multiplexers 21a and 21b and the wavelength demultiplexers 22a and 22b are formed by optical waveguide type devices such as arrayed waveguide diffraction gratings (AWG), and the band multiplexer 11 for the CL band. The band demultiplexer 12 for CL band is formed of, for example, a bulk type band demultiplexer. This bulk type band multiplexer / demultiplexer generally uses the transmission / reflection characteristics of a dielectric multilayer filter chip, and has a CL band multiplexing / demultiplexing function between a pair of collimating lens systems. The chip is arranged.

[0017]

However, the conventional optical wavelength multiplexer / demultiplexer 100 (100a) is configured by the wavelength multiplexer 2
1a and 21b are respectively formed by optical waveguide type devices,
Since the band multiplexer 11 for the CL band is formed by a bulk type device and these devices are connected via the connecting optical fiber 19, the connection loss caused by connecting the devices becomes large, There was a problem that it was not possible to meet the low loss requirements required from the system side.

This problem is caused by the optical wavelength multiplexer / demultiplexer device 1
The same applies to 00 (100b). In other words, the optical wavelength multiplexer / demultiplexer device 100 (100b) includes the wavelength demultiplexer 2
2a and 22b are formed by optical waveguide type devices, the band demultiplexer 12 for CL band is formed by bulk type devices, and these devices are connected through an optical fiber 19 for connection. Therefore, the requirement for low loss cannot be satisfied.

Further, the optical wavelength multiplexer / demultiplexer 100 (10
0a, 100b), the bulk type device is based on the spatial coupling technology, and the assembly of each module relies heavily on manual work with precise positioning and alignment, which makes it mass producible. There was also a problem that it was scarce and it was difficult to realize cost reduction.

Further, the conventional optical wavelength multiplexer / demultiplexer 100 is used.
When (100a, 100b) is housed in a package as an optical module, not only is the handling of the connecting optical fiber 19 very complicated, but it is also difficult to make the housing package small.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to be able to combine and demultiplex light with narrow wavelength intervals over a wide band, low loss, and mass producibility. -To provide a compact optical wavelength multiplexer / demultiplexer with excellent cost reduction.

[0022]

In order to achieve the above object, the present invention has the following constitution as means for solving the problem. That is, the first invention is a wideband optical wavelength multiplexing / demultiplexing circuit having a plurality of at least one of an optical input unit and an optical output unit, and a plurality of narrow spacing lights of the first to Nth (N is an integer of 2 or more). A wavelength multiplexing / demultiplexing circuit, and an optical waveguide circuit in which these narrow spacing optical wavelength multiplexing / demultiplexing circuits are connected to the corresponding optical input section or optical output section of the broadband optical wavelength multiplexing / demultiplexing circuit The first narrow spacing light wavelength multiplexing / demultiplexing circuit formed on the above multiplexes the wavelength light of the first set wavelength band, and the second narrow spacing light wavelength multiplexing / demultiplexing circuit is formed on the first narrow spacing light wavelength multiplexing / demultiplexing circuit. The first to N-th narrow spacing light wavelength multiplexing / demultiplexing circuits are different from each other in that the wavelength lights of the second setting wavelength band different from the setting wavelength band of 1 are set. Has a function of multiplexing and demultiplexing wavelength light in the wavelength band, Circuit has a means for solving the problems with that it has a structure having a function of demultiplexing a wavelength of the entire wavelength band of the combined set wavelength band of the N from the first.

The second invention, in addition to the configuration of the first invention, narrows the multiplexing / demultiplexing wavelength interval of the broadband optical wavelength multiplexing / demultiplexing circuit into a narrow spacing optical wavelength multiplexing / demultiplexing circuit. The structure that is formed larger than the interval is a means for solving the problem.

Furthermore, in addition to the structure of the first or second invention, the third invention has a structure in which two narrow spacing optical wavelength multiplexing / demultiplexing circuits are connected to one broadband optical wavelength multiplexing / demultiplexing circuit. It is a means to solve the problem.

Further, in the fourth invention, in addition to the configuration of the first, second or third invention, at least one narrow spacing optical wavelength multiplexing / demultiplexing circuit is one Mach-Zehnder optical interferometer circuit or plural connection. And a Mach-Zehnder optical interferometer circuit which is provided with a first optical waveguide and a second optical waveguide arranged in parallel with the first optical waveguide. Two directional coupling portions formed by bringing the first optical waveguide and the second optical waveguide close to each other at positions spaced apart in the longitudinal direction of the optical waveguide, and a delay sandwiched between these two directional coupling portions. A circuit is provided, and a structure in which the first optical waveguide and the second optical waveguide of the delay circuit are formed to have different lengths is a means for solving the problem.

Further, a fifth aspect of the present invention is the above-mentioned first to fourth aspects.
In addition to the configuration of any one of the inventions, the at least one narrow spacing light wavelength multiplexing / demultiplexing circuit is formed by including a circuit of an arrayed waveguide diffraction grating, and the circuit of the arrayed waveguide diffraction grating includes: At least one optical input waveguide, a first slab waveguide connected to the output end of the optical input waveguide, and a length connected to the output end of the first slab waveguide and having different set amounts from each other. , An array waveguide comprising a plurality of side-by-side channel waveguides, a second slab waveguide connected to the output end of the array waveguide, and a plurality of parallel connection to the output end of the second slab waveguide The structure having the optical output waveguide described above serves as means for solving the problem.

Further, a sixth invention is the above-mentioned first to fifth invention.
In addition to the configuration of any one of the invention, the broadband optical wavelength multiplexing / demultiplexing circuit is formed by having one Mach-Zehnder optical interferometer circuit or a plurality of connected Mach-Zehnder optical interferometer circuits. The metering circuit includes a first optical waveguide, a second optical waveguide arranged in parallel with the first optical waveguide, and the first optical waveguide and the first optical waveguide at positions spaced apart in the longitudinal direction of these optical waveguides. The first optical waveguide and the second optical waveguide of the delay circuit have two directional coupling portions formed by placing the second optical waveguide close to each other, and a delay circuit sandwiched between these two directional coupling portions. The structure in which the optical waveguides are formed to have different lengths is a means for solving the problem.

Further, in addition to the structure of the sixth invention, a seventh invention is an optical Fourier filter circuit in which the broadband optical wavelength multiplexing / demultiplexing circuit is formed by cascading two or more Mach-Zehnder interferometer circuits. The configuration has the means for solving the problem.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing the main configuration of a first embodiment of an optical wavelength multiplexer / demultiplexer according to the present invention.

The optical wavelength multiplexer / demultiplexer 1 of this embodiment is an optical waveguide circuit 1 having the circuit configuration shown in FIG.
3 is formed. The optical waveguide circuit 13 includes a wideband optical wavelength multiplexing / demultiplexing circuit 7 and a plurality of narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b from the first to the Nth (N is an integer of 2 or more, here 2). have. The wideband optical wavelength multiplexing / demultiplexing circuit 7 has a plurality of at least one (here, both) of an optical input unit 9 and an optical output unit 10, and the narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b are wideband optical wavelength multiplexing / demultiplexing circuits. Branching circuit 7
Is connected to the corresponding optical input unit 9.

That is, the optical wavelength multiplexer / demultiplexer according to the present embodiment is an optical waveguide circuit 13 in which one wideband optical wavelength multiplexer / demultiplexer circuit 7 is connected with two narrow spacing optical wavelength multiplexer / demultiplexer circuits 8a and 8b. Are formed on one substrate 20.

The first narrow spacing light wavelength multiplexing / demultiplexing circuit 8a multiplexes and demultiplexes the wavelength light in the first set wavelength band, and outputs the second wavelength.
The narrow spacing light wavelength multiplexing / demultiplexing circuit 8b has a function of multiplexing / demultiplexing wavelength light in a second setting wavelength band different from the first setting wavelength band.

The first set wavelength band is the C band, and the first narrow spacing optical wavelength multiplexing / demultiplexing circuit 8a has four wavelengths (λ1, λ2, λ2,
It has a function of multiplexing and demultiplexing lights of λ3 and λ4). The second set wavelength band is the L band, and the second narrow spacing optical wavelength multiplexing / demultiplexing circuit 8b has a frequency of 800 G within the L band.
It has a function of multiplexing and demultiplexing light of four wavelengths (λ5, λ6, λ7, λ8) at Hz intervals.

The first and second narrow spacing light wavelength multiplexing / demultiplexing circuits 8a and 8b have a function of multiplexing / demultiplexing wavelength light in the first and second set wavelength bands as described above. However, in FIG. 1, as an example thereof, the first narrow spacing light wavelength multiplexing / demultiplexing circuit 8a has a wavelength (λ) in the first set wavelength band.
1, λ2, λ3, λ4), and the second narrow spacing light wavelength multiplexing / demultiplexing circuit 8b combines lights of wavelengths (λ5, λ6, λ7, λ8) in the second set wavelength band. An example of waving is shown.

That is, as shown in FIG. 1, the wavelengths λ at the frequency of 800 GHz in the C band are respectively supplied from the four optical input sections 28 of the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a.
When light of 1, λ2, λ3, and λ4 is input, the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a multiplexes these lights into wavelength-multiplexed light. This wavelength division multiplexed light is input to the broadband optical wavelength multiplexing / demultiplexing circuit 7.

Further, the narrow spacing light wavelength multiplexing / demultiplexing circuit 8
When light of wavelengths λ5, λ6, λ7, and λ8 having a frequency of 800 GHz in the L band is input from the four optical input units 29 of b, respectively, the narrow spacing optical wavelength multiplexing / demultiplexing circuit 8b.
Converts these lights into wavelength multiplexed light. This wavelength multiplexed light is input to the broadband optical wavelength multiplexing / demultiplexing circuit 7.

The narrow spacing optical wavelength multiplexing / demultiplexing circuit 8a is
Multiple connected Mach-Zehnder optical interferometer circuits 32, 3
The narrow spacing light wavelength multiplexing / demultiplexing circuit 8b is formed to include a plurality of connected Mach-Zehnder optical interferometer circuits 35, 36, 37.

In the Mach-Zehnder interferometer circuit, for example, as shown in FIG. 2, a first optical waveguide 41, a second optical waveguide 42 arranged in parallel with the first optical waveguide 41, and these optical waveguides 41. , 42, two directional coupling portions 43 formed by bringing the first optical waveguide 41 and the second optical waveguide 42 close to each other at positions spaced apart from each other in the longitudinal direction, and the two directional coupling portions 43. It has a sandwiched delay circuit 44. The first optical waveguide 41 and the second optical waveguide 42 of the delay circuit 44 are formed to have different lengths.

As shown in FIG. 1, the Mach-Zehnder optical interferometer circuits 32, 33 and 34 forming the narrow spacing optical wavelength multiplexing / demultiplexing circuit 8a are connected in a tree shape, and 800 GHz
Optical output sides of the 1600 GHz spacing Mach-Zehnder optical interferometer circuits 33 and 34 are connected to the optical input side of the z-spacing Mach-Zehnder optical interferometer circuit 32, respectively.

Further, the narrow spacing light wavelength multiplexing / demultiplexing circuit 8
Mach-Zehnder optical interferometer circuits 35, 36 forming b
37 is connected in a tree shape, and 16 is connected to the optical input side of the Mach-Zehnder interferometer circuit 35 with 800 GHz spacing.
The optical output sides of Mach-Zehnder optical interferometer circuits 36 and 37 of 00 GHz spacing are respectively connected.

A method of designing a circuit in which Mach-Zehnder optical interferometer circuits are connected in multiple stages as described above is described in, for example, N. Takato et al., J. Lightwave Technol., Vol.
It is described in various documents such as 6, pp.1003-1010,1988.

The broadband optical wavelength multiplexing / demultiplexing circuit 7 has an optical Fourier filter circuit 31 formed by connecting two Mach-Zehnder optical interferometer circuits 40a and 40b in cascade. As shown in FIG. 3, the optical Fourier filter circuit 31 includes a total of two delay circuits 44 sandwiched between three directional coupling sections 43 and adjacent directional coupling sections 43.
(44a, 44b).

An optical Fourier filter circuit formed by cascading Mach-Zehnder interferometer circuits is, for example, as shown in FIG. 4, M + 1 (M is an integer of 2 or more) directional coupling portions 43 and M. It has a number of delay circuits 44, and by appropriately setting the configuration of the delay circuits 44, the transfer function from any input port to any output port can be expanded into a Fourier series. is there.
The difference in length between the first optical waveguide 41 and the second optical waveguide 42 in each delay circuit 44 is called the delay amount.

The design method of the optical Fourier filter is, for example,
C.Huang et al., NFOEC'99, Proc., Pp.311-316 (1999)
H.Arai et al., NFOEC'99, Proc., Pp.444-451 (199
9) and the like, the method of designing the optical Fourier filter circuit applied to this embodiment is not limited to these documents and the like.

As shown in FIG. 3, in the present embodiment, the optical Fourier filter circuit 31 forming the wideband optical wavelength multiplexing / demultiplexing circuit 7 is an optical Fourier filter circuit with M = 2, and includes the delay circuit 44a. The absolute value ratio of the delay amount of the delay circuit 44b is 1: 2.

The insertion loss spectrum of the broadband optical wavelength multiplexing / demultiplexing circuit 7 has a square wave response as shown in FIG. The broadband optical wavelength multiplexing / demultiplexing circuit 7, as shown in FIG.
For example, it has a function of passing light in a wavelength band centering on a central wavelength of 1550 nm of the C band (wavelength 1530 nm to 1570 nm). In addition, the broadband optical wavelength multiplexing / demultiplexing circuit 7
Has a function of transmitting light in a wavelength band centered on a central wavelength of 1590 nm in the L band (wavelengths 1570 nm to 1610 nm).

Since the wavelength division / multiplexing wavelength interval of the broadband optical wavelength multiplexer / demultiplexer circuit 7 is the distance between the two passing center wavelengths (1550 nm and 1590 nm) of the insertion loss spectrum shown in FIG. 5, its value is It is about 40 nm, which is 5000 GHz when converted to a frequency. This value is larger than 800 GHz which is the wavelength division wavelength division wavelength of the narrow spacing light wavelength division multiplexing circuits 8a and 8b.

Since it has the above-mentioned function, the wideband optical wavelength multiplexing / demultiplexing circuit 7 has the first to Nth setting wavelength bands (here, the first setting wavelength band C band and the second setting wavelength band). (L band) which is the total wavelength band of the entire wavelength band.

For example, the broadband optical wavelength multiplexing / demultiplexing circuit 7 has a C
When the wavelength-multiplexed light having a plurality of wavelengths within the band and the wavelength-multiplexed light having a plurality of wavelengths within the L band are respectively input, these wavelength-multiplexed lights are combined to reach from the C band to the L band. It outputs wavelength-multiplexed light having a plurality of wavelengths within the wavelength range.

Further, when the wavelength multiplexed light having a plurality of wavelengths from the C band to the L band is input, the broadband optical wavelength multiplexing / demultiplexing circuit 7 has the wavelength multiplexed light having a plurality of wavelengths in the C band. The wavelength division multiplexed light and the wavelength division multiplexed light having a plurality of wavelengths in the L band are demultiplexed.

FIG. 1 shows a frequency 800 from the optical input units 28 and 29 of the narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b.
An example is shown in which light of a total of 8 wavelengths at GHz intervals is input, and in this case, the broadband optical wavelength multiplexing / demultiplexing circuit 7 exerts a function of multiplexing the lights of 8 wavelengths.

In other words, the wideband optical wavelength multiplexing / demultiplexing circuit 7 has four wavelengths (λ) in the C band at the frequency of 800 GHz, which are multiplexed by the spacing optical wavelength multiplexing / demultiplexing circuit 8a.
1, λ2, λ3, λ4) and four wavelengths (λ5, L) in the L band with a frequency of 800 GHz, which are multiplexed by the narrow spacing light wavelength multiplexing / demultiplexing circuit 8b.
When λ6, λ7, λ8) are input to the broadband optical wavelength multiplexing / demultiplexing circuit 7, these wavelength multiplexed lights are multiplexed.

The example of the present embodiment is configured as described above. Here, a method of manufacturing the optical wavelength multiplexer / demultiplexer 1 of the example of the present embodiment will be described. First, a lower clad layer containing SiO ₂ as a main component is deposited on a silicon substrate 20 by a flame deposition method, and then a core layer containing SiO ₂ as a main component to which GeO ₂ is added as a dopant is deposited. The core layer and the lower clad layer are made into transparent glass.

Next, the circuit pattern of the optical waveguide circuit 13 is transferred by the photolithography technique, and the optical waveguide is patterned by etching. Finally, again SiO
An upper clad layer containing ₂ as a main component is deposited to form a transparent glass. With this manufacturing method, the cross-sectional shape of the core is 6.5 μm.
A waveguide forming region was formed on the substrate 20 with a size of × 6.5 μm and a relative refractive index difference between the core and the clad being 0.8%.

The example of the present embodiment is configured as described above, and as shown in FIG. 1, each of the four optical input sections 28 of the narrow spacing optical wavelength multiplexing / demultiplexing circuit 8a receives a frequency of 800 GHz in the C band. Interval wavelengths λ1, λ2, λ3, λ
When the light of No. 4 is input, these lights are multiplexed by the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a, and the wideband optical wavelength multiplexing / demultiplexing circuit 7
The light is input from the optical input unit 9 on one side (one end side of the first optical waveguide 41 of the optical Fourier filter circuit 31) to the broadband optical wavelength multiplexing / demultiplexing circuit 7.

At the same time, the wavelengths λ5, λ6, λ at the frequency of 800 GHz in the L band are respectively supplied from the four optical input sections 29 of the narrow spacing light wavelength multiplexing / demultiplexing circuit 8b.
When light of wavelengths 7 and λ8 is input, these lights are multiplexed by the narrow spacing optical wavelength multiplexer / demultiplexer circuit 8b, and the other side of the broadband optical wavelength multiplexer / demultiplexer circuit 7 (optical Fourier filter circuit 31 From the one end side of the second optical waveguide 42) to the broadband optical wavelength multiplexing / demultiplexing circuit 7.

Then, the wavelengths λ1, λ2, λ3, λ in the C band inputted to the broadband optical wavelength multiplexing / demultiplexing circuit 7, respectively.
Wavelength-division multiplexed light having 4 and wavelengths λ5, λ6 in the L band,
The broadband optical wavelength multiplexer / demultiplexer circuit 7 multiplexes the wavelength multiplexed light having λ7 and λ8, and outputs it from the optical output unit 30 of the optical wavelength multiplexer / demultiplexer 1.

FIG. 6 shows a combined optical spectrum when the lights of λ1, λ2, λ3, and λ4 in the C band and the wavelengths λ5, λ6, λ7, and λ8 in the L band are combined according to the present embodiment. Show. As is clear from FIG. 6, this embodiment example is
It was possible to combine light with narrow wavelength intervals with low loss over a wide band from the C band to the L band.

In this embodiment, as shown in FIG. 1, the optical waveguide circuit 13 in which the narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b and the broadband optical wavelength multiplexing / demultiplexing circuit 7 are connected is provided on the substrate 20. Since it is formed as described above, it is possible to realize a compact optical wavelength multiplexer / demultiplexer 1 that is excellent in mass productivity and cost reduction.

FIG. 7 shows a second embodiment of the optical wavelength multiplexer / demultiplexer according to the present invention. In the second embodiment, the configuration of the narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b is the first.
The configuration is the same as that of the first embodiment except that the configuration is different from that of the first embodiment. In the description of the second embodiment, the same components as those of the first embodiment will be designated by the same reference numerals, and redundant description with the description of the first embodiment will be omitted or simplified.

In the second embodiment, the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a is formed by including a plurality of connected Mach-Zehnder optical interferometer circuits 38a, 38b, 33, 34. Mach-Zehnder optical interferometer circuits 38a, 3
8b are connected in cascade to form an optical Fourier filter circuit 48 of 800 GHz spacing. The optical Fourier filter circuit 48, as shown in FIG.
The absolute value ratio of the delay amounts of a and the delay circuit 44b is 2: 1.

The optical Fourier filter circuit 48 and the Mach-Zehnder optical interferometer circuits 33 and 34 are connected in a tree shape, and the optical input side of the optical Fourier filter circuit 48 is provided with 160
Mach-Zehnder optical interferometer circuit 3 with 0 GHz spacing
The light output units of 3, 34 are respectively connected.

The narrow spacing light wavelength multiplexing / demultiplexing circuit 8b is
Multiple connected Mach-Zehnder optical interferometer circuits 39a, 3a
9b, 36, 37. The Mach-Zehnder optical interferometer circuits 39a and 39b are connected in cascade,
Optical Fourier Filter Circuit 49 with 00 GHz Spacing
Is formed. Like the optical Fourier filter circuit 48, the optical Fourier filter circuit 49 also has a circuit configuration as shown in FIG. 8, and the absolute value ratio of the delay amounts of the delay circuits 44a and 44b is 2: 1.

The optical Fourier filter circuit 49 and the Mach-Zehnder optical interferometer circuits 36 and 37 are connected in a tree shape.
Mach-Zehnder optical interferometer circuit 3 with 0 GHz spacing
The light output units 6 and 37 are connected to each other.

The example of the second embodiment is constructed as described above, and the example of the second embodiment is also manufactured by the manufacturing method similar to that of the first embodiment, and performs the same operation.

FIG. 9 shows the above C according to the second embodiment.
7 shows a combined light spectrum when the lights of λ1, λ2, λ3, and λ4 in the band are combined with the wavelengths λ5, λ6, λ7, and λ8 in the L band.

As is apparent from FIG. 9, the combined light spectrum has the respective wavelengths λ1, λ2, λ3, λ4, λ5, λ.
The spectrum has a shape close to a rectangular shape centered around 6, λ7, λ8, and has respective wavelengths λ1, λ2, λ3, λ4, λ5, λ.
The loss around 6, λ7 and λ8 was very small.

As described above, in the second embodiment, each wavelength λ
Wavelengths around 1, λ2, λ3, λ4, λ5, λ6, λ7, and λ8 can be combined with low loss, and a combined optical spectrum having a spectrum close to a rectangular shape centered on these wavelengths can be obtained. Since it can be obtained, it is possible to realize the optical wavelength multiplexer / demultiplexer 1 having a wider pass band than that of the first embodiment.

Further, in the second embodiment, as in the first embodiment, the narrow spacing optical wavelength multiplexing / demultiplexing circuit 8a,
Since the optical waveguide circuit 13 in which 8b and the wideband optical wavelength multiplexer / demultiplexer circuit 7 are connected is formed on the substrate 20, a compact optical wavelength multiplexer / demultiplexer excellent in mass productivity and cost reduction can be realized.

FIG. 10 shows a third embodiment of the optical wavelength multiplexer / demultiplexer according to the present invention. Also in the third embodiment, as in the first and second embodiments, an optical waveguide circuit in which two narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b are connected to one broadband optical wavelength multiplexing / demultiplexing circuit 7. 13 for one substrate 2
It is formed on 0.

Also in the third embodiment, the first narrow spacing light wavelength multiplexing / demultiplexing circuit 8a multiplexes and demultiplexes the wavelength light in the first set wavelength band to generate the second narrow spacing light wavelength. The multiplexing / demultiplexing circuit 8b has a second wavelength different from the first set wavelength band.
It has a function of multiplexing and demultiplexing the wavelength light in the set wavelength band of. The first set wavelength band is the C band, and the second set wavelength band is the L band.

One of the characteristic configurations of the third embodiment is:
First and second narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a, 8
b is formed by the circuits 51 and 52 of the arrayed waveguide diffraction grating.

The circuit of the arrayed waveguide diffraction grating is connected to at least one optical input waveguide 2 and the output end of the optical input waveguide 2 as shown in FIGS. The first slab waveguide 3 and an array waveguide 4 which is connected to the output end of the first slab waveguide 3 and includes a plurality of channel waveguides 4a that are arranged in parallel and have different lengths. A second slab waveguide 5 connected to the output end of the arrayed waveguide 4 and a plurality of optical output waveguides 6 connected in parallel to the output end of the second slab waveguide 5 are provided.

The circuits 51 and 52 of the arrayed-waveguide diffraction grating applied to the third embodiment each have a plurality of optical input waveguides 2, one of which has a wide-band optical wavelength division. Each of them is connected to the corresponding optical output section 10 of the wave circuit 7.

In the arrayed waveguide diffraction grating circuit, the arrayed waveguide 4 propagates the light derived from the first slab waveguide 3, and is formed by arranging a plurality of channel waveguides 4a in parallel. Has been done. The lengths of the adjacent channel waveguides 4a differ from each other by a set amount (ΔL).

The channel waveguides 4a constituting the arrayed waveguide 4 are usually provided in a large number such as 100, and the optical output waveguides 6 are demultiplexed or combined with each other by, for example, an arrayed waveguide diffraction grating. Although it is provided corresponding to the number of signal lights of different wavelengths, FIG.
0 and FIG. 11, the number of each of the channel waveguides 4a, the optical output waveguides 6 and the optical input waveguides 2 is simply shown for simplification of the drawing.

In the circuit of the arrayed waveguide diffraction grating, for example, as shown in FIG. 11A, one optical input waveguide 2 is wavelength-multiplexed with wavelengths λ1, λ2, λ3, ... λn. When light is introduced, this wavelength-multiplexed light is introduced into the first slab waveguide 3 through the optical input waveguide 2, spreads due to its diffraction effect, enters the array waveguide 4, and propagates in the array waveguide 4. To do.

The light propagated through the arrayed waveguide 4 is
Of the array waveguide 4 is reached by the optical output waveguide 6, and all the channel waveguides 4a of the array waveguide 4 have different lengths. After propagating, there is a phase shift of individual light,
The wavefront of the focused light is tilted according to the amount of deviation, and the tilt angle determines the position where light is focused.

Therefore, the condensing positions of the light beams having different wavelengths are different from each other, and the light output waveguides 6 having different wavelengths are formed by forming the light output waveguides 6 at the positions. Can be output from.

Since the arrayed waveguide diffraction grating utilizes the principle of reciprocity (reversibility) of the optical circuit, it has an optical multiplexing function as well as an optical demultiplexing function. That is, FIG.
(B), when a plurality of lights having different wavelengths, for example, wavelengths λ1, λ2, λ3, ... λn are made incident from the respective optical output waveguides 6, these lights are reverse to the above. The second slab waveguide 5 and the arrayed waveguide 4 pass through the propagation path.
And the first slab waveguide 3 combine and the light is emitted from one optical input waveguide 2.

In the third embodiment, the first narrow spacing light wavelength multiplexing / demultiplexing circuit 8a is a 16-channel arrayed waveguide diffraction grating circuit 5 with 100 GHz spacing.
1 and has a function of multiplexing / demultiplexing light of 16 wavelengths (λ1, λ2, ..., λ16) in the C band at intervals of 100 GHz.

The second narrow spacing light wavelength multiplexing / demultiplexing circuit 8b is a circuit 52 of an arrayed waveguide diffraction grating of 16 channels with 100 GHz spacing, and has 16 wavelengths (λ1 at intervals of 100 GHz in the L band).
, Λ18, ..., λ32).

The narrow spacing optical wavelength multiplexing / demultiplexing circuit 8
As described above, a and 8b have a function of multiplexing and demultiplexing wavelength light within the first and second set wavelength bands (C band, L band), and FIG. 10 shows an example thereof. , The narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b are respectively
An example of demultiplexing the wavelength light in the second set wavelength band is shown.

Further, as shown in FIG. 10, in the third embodiment, the broadband optical wavelength multiplexing / demultiplexing circuit 7 is an optical Fourier rectifier formed by connecting three Mach-Zehnder interferometer circuits 60a, 60b, 60c in cascade. It has a filter circuit 56.

This optical Fourier filter circuit 56 is shown in FIG.
As shown in FIG. 2, it has four directional coupling portions 43 and a total of three delay circuits 44 (44a, 44b, 44c) sandwiched between adjacent directional coupling portions 43. The absolute value ratio of the delay amounts of the delay circuits 44a, 44b and 44c is formed to be about 1: 2: 4.

The wideband optical wavelength multiplexing / demultiplexing circuit 7 is a total wavelength band including the first to Nth (here, N = 2) set wavelength bands, that is, the first set wavelength band (C
Band) and the second set wavelength band (L band) are combined to have a function of multiplexing / demultiplexing wavelength lights in all wavelength bands.

The wideband optical wavelength multiplexing / demultiplexing circuit 7 has, for example, a center wavelength of 1 in the C band (wavelength 1530 nm to 1570 nm).
Wavelength band centered around 550 nm and L band (wavelength 15
(70 nm to 1610 nm) having a center wavelength of 1590 nm.

Further, since the wavelength division / multiplexing wavelength interval of the broadband optical wavelength multiplexing / demultiplexing circuit 7 is the distance between the above two passing center wavelengths (1550 nm and 1590 nm), the value is about 40 n.
m, which is 5000 GHz when converted to frequency.
This value is equal to the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a,
This is larger than 100 GHz which is the wavelength division wavelength of 8b.

With this configuration, the wideband optical wavelength multiplexing / demultiplexing circuit 7 has a frequency of 100 G as shown in FIG.
When wavelength-multiplexed light having 32 wavelengths λ1 to λ32 in the wavelength range from the C band to the L band at the Hz interval is input, the wavelength-multiplexed light is converted into 16 wavelengths (λ
It has a function of demultiplexing into wavelength multiplexed light having 1 to λ16) and wavelength multiplexed light having 16 wavelengths in the L band (λ17 to λ32).

The third embodiment is configured as described above, and the third embodiment is also manufactured by the same manufacturing method as the first and second embodiments.

In the third embodiment, for example, FIG.
As shown in 0, when wavelength-multiplexed light having 32 wavelengths λ1 to λ32 is input from the optical input unit 70 of the optical wavelength multiplexer / demultiplexer 1, the wavelength-multiplexed light is divided into broadband wavelength-multiplexed wavelengths. The wave circuit 7 includes wavelength-multiplexed light having 16 wavelengths (λ1 to λ16) in the C band and 16 wavelengths (λ17 to λ) in the L band.
32) is demultiplexed into wavelength-division multiplexed light.

16 wavelengths λ1 to λ16 in the C band
The wavelength-division-multiplexed light with is input to the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a. Then, the wavelength-division-multiplexed light is demultiplexed by the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a into lights of respective wavelengths, which are output from the corresponding optical output units 71.

The 16 wavelengths λ17 to λ in the L band
The wavelength multiplexed light having 32 is input to the narrow spacing light wavelength multiplexing / demultiplexing circuit 8b. Then, the wavelength-division-multiplexed light is demultiplexed by the narrow spacing light wavelength multiplexing / demultiplexing circuit 8b into lights of respective wavelengths, which are output from the corresponding optical output units 72.

FIG. 13 shows a demultiplexed light spectrum of the optical wavelength multiplexer / demultiplexer according to the third embodiment. As is clear from FIG. 13, the optical wavelength multiplexer / demultiplexer of the third embodiment has a C
, Λ16 in the band and light of λ17, λ18, ..., λ32 in the L band,
Can be demultiplexed with the same low loss.

Also in the third embodiment, as shown in FIG. 10, the optical waveguide circuit 13 in which the narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b and the broadband optical wavelength multiplexing / demultiplexing circuit 7 are connected.
Since it is formed on the substrate 20, it is possible to realize a compact optical wavelength multiplexer / demultiplexer 1 excellent in mass productivity and cost reduction.

FIG. 14 shows a fourth embodiment of the optical wavelength multiplexer / demultiplexer according to the present invention. The fourth embodiment is configured almost in the same manner as the third embodiment, and the fourth embodiment is different from the third embodiment in that the first set wavelength band is the S band. And the second set wavelength band is the C band. S band is 149
It is a wavelength band of 0 nm to 1530 nm.

In the fourth embodiment, the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a has the first setting wavelength band S.
It is formed by a circuit 53 of an arrayed waveguide diffraction grating having a function of multiplexing / demultiplexing light of 16 wavelengths (λ1, λ2, ..., λ16) having a frequency of 100 GHz in the band.

The second narrow spacing light wavelength multiplexing / demultiplexing circuit 8b has a function of multiplexing / demultiplexing light of 16 wavelengths (λ17, λ18, ..., λ32) having a frequency of 100 GHz in the C band. It is formed by the circuit 51 of the arrayed waveguide diffraction grating.

The narrow spacing light wavelength multiplexing / demultiplexing circuit 8
As described above, a and 8b have a function of multiplexing and demultiplexing the wavelength lights of the first and second set wavelength bands, but FIG.
As an example thereof, a narrow spacing light wavelength multiplexing / demultiplexing circuit 8
a and 8b show examples of demultiplexing wavelength lights in the first and second set wavelength bands, respectively.

Further, as shown in FIG. 14, in the fourth embodiment, the broadband optical wavelength multiplexing / demultiplexing circuit 7 is an optical Fourier rectifier formed by connecting three Mach-Zehnder optical interferometer circuits 61a, 61b and 61c in cascade. It has a filter circuit 57.

This optical Fourier filter circuit 57 is shown in FIG.
As shown in FIG. 2, it has four directional coupling portions 43 and a total of three delay circuits 44 (44a, 44b, 44c) sandwiched between adjacent directional coupling portions 43.
The absolute value ratio of the delay amounts of the delay circuits 44a, 44b and 44c is formed to be about 1: 2: 4.

The broadband optical wavelength multiplexing / demultiplexing circuit 7 has a function of multiplexing / demultiplexing wavelength light in all wavelength bands including the first set wavelength band (S band) and the second set wavelength band (C band). Have

The wide band optical wavelength multiplexing / demultiplexing circuit 7 has, for example, a center wavelength 151 of the S band (1490 nm to 1530 nm).
Wavelength band centered on 0 nm and C band (1530 nm
.About.1570 nm) having a center wavelength of 1550 nm.

Further, the multiplexing / demultiplexing wavelength interval of the broadband optical wavelength multiplexing / demultiplexing circuit 7 is set to the above-mentioned passing center wavelength (1510 nm and 1
550 nm), the value is about 40 nm.
Which is 5000 GHz when converted to a frequency. This value is equal to the narrow spacing light wavelength multiplexing / demultiplexing circuits 8a, 8
It is larger than 100 GHz which is the wavelength division wavelength of b in FIG.

With this configuration, the wideband optical wavelength multiplexing / demultiplexing circuit 7 has a frequency of 100 G as shown in FIG.
When wavelength-multiplexed light having 32 wavelengths λ1 to λ32 in the wavelength range from the S band to the C band at Hz intervals is input, the wavelength multiplexed light is converted into 16 wavelengths in the S band (λ1 to λ16). Wavelength-multiplexed light with 1 and 1 in C band
It has a function of demultiplexing into wavelength division multiplexed light having 6 wavelengths (λ17 to λ32).

The fourth embodiment is constructed as described above, and the fourth embodiment is also manufactured by the same manufacturing method as the third embodiment.

In the fourth embodiment, for example, as shown in FIG.
As shown in FIG. 4, when wavelength-multiplexed light having 32 wavelengths λ1 to λ32 is input from the optical input unit 70 of the optical wavelength multiplexer / demultiplexer 1, the wavelength-multiplexed light is converted into the broadband optical wavelength The demultiplexing circuit 7 has 16 wavelengths in the S band (λ1 to λ1
6) and 16 wavelengths in the C band (λ1
7 to λ32) and demultiplexed into wavelength division multiplexed light.

The 16 wavelengths λ1 in the S band
The wavelength multiplexed light having .about..lamda.16 is input to the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a. Then, the wavelength-division-multiplexed light is demultiplexed by the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a into lights of respective wavelengths, which are output from the corresponding optical output units 71.

The 16 wavelengths λ17 to λ in the C band
The wavelength multiplexed light having 32 is input to the narrow spacing light wavelength multiplexing / demultiplexing circuit 8b. Then, the wavelength-division-multiplexed light is demultiplexed by the narrow spacing light wavelength multiplexing / demultiplexing circuit 8b into lights of respective wavelengths, which are output from the corresponding optical output units 72.

FIG. 15 shows the demultiplexed light spectrum of the optical wavelength multiplexer / demultiplexer according to the fourth embodiment. As is clear from FIG. 15, the optical wavelength multiplexer / demultiplexer of the fourth embodiment has an S
, Λ16 within the band, and λ17, λ18, ..., λ32 within the C band,
Can be demultiplexed with the same low loss.

Further, in the fourth embodiment, as shown in FIG. 14, the optical waveguide circuit 13 in which the narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b and the broadband optical wavelength multiplexing / demultiplexing circuit 7 are connected.
Since it is formed on the substrate 20, it is possible to realize a compact optical wavelength multiplexer / demultiplexer 1 excellent in mass productivity and cost reduction.

FIG. 16 shows a fifth embodiment of the optical wavelength multiplexer / demultiplexer according to the present invention. The optical wavelength multiplexer / demultiplexer 1 according to the fifth embodiment also includes the optical waveguide circuit 13 formed on the substrate 20.

The optical waveguide circuit 13 includes a wide band optical wavelength multiplexing / demultiplexing circuit 7 and a plurality of narrow spacing optical wavelength multiplexing / demultiplexing circuits 1 to N (N is an integer of 2 or more, here 3). 8
a, 8b, 8c. These narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a, 8b, 8c are connected to the corresponding optical output section 10 of the broadband optical wavelength multiplexing / demultiplexing circuit 7.

The first narrow spacing light wavelength multiplexing / demultiplexing circuit 8a has a function of multiplexing / demultiplexing wavelength light in the first set wavelength band, and the second narrow spacing light wavelength multiplexing / demultiplexing circuit 8b. Has a function of multiplexing / demultiplexing wavelength light in a second setting wavelength band different from the first setting wavelength band, and the third narrow spacing light wavelength multiplexing / demultiplexing circuit 8c is provided in the first and second wavelength bands. It has a function of multiplexing and demultiplexing the wavelength light of the third setting wavelength band different from the setting wavelength band.

That is, the first, second, and third narrow spacing light wavelength multiplexing / demultiplexing circuits 8a, 8b, 8c combine the wavelength lights of the first, second, and third set wavelength bands which are different from each other. It has a wave function.

In the fifth embodiment, the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a has the first setting wavelength band S.
It has a circuit 53 of an arrayed-waveguide diffraction grating having a function of multiplexing and demultiplexing light of 16 wavelengths (λ1 to λ16) at a frequency of 100 GHz in the band.

The second narrow spacing light wavelength multiplexing / demultiplexing circuit 8b has 16 wavelengths (λ17 to λ3) at 100 GHz intervals in the L band which is the second set wavelength band.
It has a circuit 52 of an arrayed waveguide diffraction grating having a function of multiplexing / demultiplexing the light of 2).

Further, the third narrow spacing light wavelength multiplexing / demultiplexing circuit 8c has 16 wavelengths (λ33 to λ) at intervals of 100 GHz in the C band which is the third set wavelength band.
It has a circuit 51 of an arrayed waveguide diffraction grating having a function of multiplexing / demultiplexing the light of 48).

The narrow spacing light wavelength multiplexing / demultiplexing circuit 8
As described above, a, 8b, and 8c have a function of multiplexing and demultiplexing the wavelength light in the first, second, and third set wavelength bands, and FIG. An example is shown in which the pacing light wavelength multiplexing / demultiplexing circuits 8a, 8b, and 8c demultiplex the wavelength light in the first, second, and third set wavelength bands, respectively.

The broadband optical wavelength multiplexing / demultiplexing circuit 7 has the first
Setting wavelength band (S band) and second setting wavelength band (L
Band) and the third set wavelength band (C band) are combined to have a function of multiplexing / demultiplexing wavelength light in the entire wavelength band.

The wideband optical wavelength multiplexing / demultiplexing circuit 7 has, for example, a central wavelength 151 of the S band (1490 nm to 1530 nm).
Wavelength band centered on 0 nm and C band (1530 nm
˜1570 nm) center wavelength of 1550 nm and L band (wavelength 1570 nm to 1610 n)
It has a function of passing light in the wavelength band centered at the central wavelength of 1590 nm in m).

Since the wavelength division / multiplexing wavelength interval of the wideband optical wavelength multiplexer / demultiplexer circuit 7 is the distance between the above three pass center wavelengths (1510 nm, 1550 nm and 1590 nm), the value is about 40 nm and the frequency is about 40 nm. Converted to 5000
GHz. This value is 100 GH, which is the wavelength division wavelength of the narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b.
Larger than z.

With this configuration, the wideband optical wavelength multiplexing / demultiplexing circuit 7 has a frequency of 100 G as shown in FIG.
When wavelength-multiplexed light having 48 wavelengths λ1 to λ48 in the wavelength range from the S band to the L band at Hz intervals is input, the wavelength multiplexed light is converted into 16 wavelengths in the S band (λ1 to λ16). Wavelength-multiplexed light having a wavelength of 16 wavelengths in the L band (λ17 to λ32), and C
It has a function of demultiplexing into wavelength division multiplexed light having 16 wavelengths within the band (λ33 to λ48).

The broadband optical wavelength multiplexing / demultiplexing circuit 7 is formed by connecting the optical Fourier filter circuits 58 and 59 in two stages. The optical Fourier filter circuit 58 is formed by connecting three Mach-Zehnder optical interferometer circuits 62a, 62b, 62c in cascade, and the optical Fourier filter circuit 58 is formed by connecting three Mach-Zehnder optical interferometer circuits 63a, 63b, 63c in cascade.

These optical Fourier filter circuits 58, 5
As shown in FIG. 12, reference numeral 9 denotes a total of three delay circuits 44 (44a, 44b, 4) sandwiched between four directional coupling portions 43 and adjacent directional coupling portions 43, respectively.
4c). Delay circuits 44a, 44b, 44c
The absolute value ratios of the delay amounts are about 1: 2: 4.

The optical Fourier filter circuit 59 has a central wavelength 151 of the S band (wavelength 1490 nm to 1530 nm).
Wavelength band centered on 0 nm and L band (wavelength 1570
(nm to 1610 nm) has a function of passing light in a wavelength band centered at a central wavelength of 1590 nm.

The optical Fourier filter circuit 58 has a center wavelength of 1550 n in the C band (1530 nm to 1570 nm).
The wavelength band centered on m and the central wavelength of the S band 1510
wavelength band centered at nm, central wavelength of L band 1590
It has a function of passing light in a wavelength band centered on nm.

The fifth embodiment is constructed as described above, and the fifth embodiment is also manufactured by the same manufacturing method as the third and fourth embodiments.

In the fifth embodiment, for example, FIG.
As shown in FIG. 6, from the optical input unit 70 of the optical wavelength multiplexer / demultiplexer 1, light with 16 wavelengths λ1 to λ16 in the S band, light with 16 wavelengths λ17 to λ32 in the L band, and light in the C band. 1
When wavelength division multiplexed light having lights of 6 wavelengths λ33 to λ48 is input, the wavelength division multiplexed light is input to the broadband optical wavelength multiplexing / demultiplexing circuit 7
Are wavelength-multiplexed light having 16 wavelengths λ1 to λ16 in the S band, wavelength multiplexed light having 16 wavelengths λ17 to λ32 in the L band, and wavelength multiplexed light having 16 wavelengths λ33 to λ48 in the C band. Demultiplex into.

The wavelength-multiplexed light having the wavelength in the S band is input to the narrow spacing light wavelength multiplexing / demultiplexing circuit 8a, and the wavelength-multiplexed light having the wavelength in the L band is input to the narrow spacing light wavelength multiplexing / demultiplexing circuit. The wavelength division multiplexed light having a wavelength in the C band is input to the demultiplexing circuit 8b and is input to the narrow spacing light wavelength multiplexing / demultiplexing circuit 8c.

The narrow spacing light wavelength multiplexing / demultiplexing circuit 8a is
The wavelength-multiplexed light having the wavelengths λ1, λ2, ..., λ16 in the S band is demultiplexed into lights of respective wavelengths, which are output from the corresponding light output units 71.

Further, the narrow spacing light wavelength multiplexing / demultiplexing circuit 8
b is 16 wavelengths in the L band λ17, λ18, ...
The wavelength-multiplexed light having .lambda.32 is demultiplexed into lights of respective wavelengths, which are output from the corresponding optical output units 72.

Further, the narrow spacing light wavelength multiplexing / demultiplexing circuit 8c has 16 wavelengths λ33, λ34, ...
.., demultiplexes the wavelength-multiplexed light having .lamda.48 into light of each wavelength, and outputs the light from the corresponding light output units 73.

FIG. 17 shows the demultiplexed light spectrum of the optical wavelength multiplexer / demultiplexer 1 of the fifth embodiment. As is apparent from FIG. 17, the optical wavelength multiplexer / demultiplexer 1 of the fifth embodiment example
Is light having wavelengths λ1 to λ16 in the S band, light having wavelengths λ17 to λ32 in the L band, and wavelengths λ33 to λ in the C band.
48 lights can be demultiplexed with the same level of low loss.

In the fifth embodiment, as shown in FIG. 16, the narrow spacing light wavelength multiplexing / demultiplexing circuits 8a, 8b,
Since the optical waveguide circuit 13 in which the 8c and the broadband optical wavelength multiplexing / demultiplexing circuit 7 are connected is formed on the substrate 20, the compact optical wavelength multiplexing / demultiplexing device 1 excellent in mass productivity and cost reduction can be realized.

The present invention is not limited to the above-mentioned embodiments, but can take various modes. For example, in the first and second embodiments described above, the narrow spacing optical wavelength multiplexing / demultiplexing circuits 8a and 8b are formed by including a plurality of connected Mach-Zehnder interferometer circuits, but at least one narrow spacing is provided. The optical wavelength multiplexing / demultiplexing circuit may be configured to have one Mach-Zehnder optical interferometer circuit.

Further, the at least one narrow spacing optical wavelength multiplexing / demultiplexing circuit may have a structure including one optical Fourier filter circuit formed by connecting a plurality of Mach-Zehnder optical interferometer circuits in cascade. As described above, the configuration of the narrow spacing light wavelength multiplexing / demultiplexing circuit is not particularly limited and may be set appropriately.

Further, in each of the above embodiments, the broadband optical wavelength multiplexing / demultiplexing circuit 7 is formed by the optical Fourier filter circuit which is formed by connecting a plurality of Mach-Zehnder optical interferometer circuits in cascade. The wave circuit 7 may be formed to have one Mach-Zehnder interferometer circuit.

For example, FIG. 18 shows an example in which the broadband optical wavelength multiplexing / demultiplexing circuit 7 is formed by one Mach-Zehnder optical interferometer circuit 46. This example has the same configuration as that of the first embodiment except for the configuration of the broadband optical wavelength multiplexing / demultiplexing circuit 7.

As shown in FIG. 19, the broadband optical wavelength multiplexing / demultiplexing circuit 7 including the Mach-Zehnder interferometer circuit 46 has, for example, a wavelength band centering on the center wavelength 1550 nm of the C band and a center wavelength 1590 nm of the L band. It has the function of passing light in the central wavelength band. However, the shape of the insertion loss spectrum is different from the insertion loss spectrum (FIG. 5) of the optical Fourier filter circuit 31.

In FIG. 20, light of four wavelengths (λ1, λ2, λ3, λ4) having a frequency of 800 GHz in the C band and light having a frequency of 800 GHz in the L band are used by the optical wavelength multiplexer / demultiplexer shown in FIG. 4 wavelengths (λ5, λ6, λ7, λ
The combined light spectrum when the 8) is combined is shown.
As in the first embodiment, as shown in FIG. 20, the configuration example shown in FIG. 18 can also combine light with narrow wavelength intervals with low loss over a wide band from the C band to the L band.

However, the combined light spectrum shown in FIG. 20 and the combined light spectrum of the first embodiment are shown in FIG.
Comparing with, in the combined light spectrum shown in FIG. 20, the insertion loss at wavelengths λ4, λ1, λ8 and λ5 is slightly higher, whereas in the combined light spectrum shown in FIG. λ2, λ3, λ4, λ5, λ
There is almost no difference in the insertion loss of all the light of 6, λ7, and λ8.

As described above, when the broadband optical wavelength multiplexing / demultiplexing circuit 7 is formed by the optical Fourier filter circuit 31, the loss values of all wavelength lights can be made to be a very low loss and uniform value. The reason for this is that the optical Fourier filter circuit 3
This is because the insertion loss spectrum of No. 1 has a square response as shown in FIG.

Furthermore, each of the above-described embodiments has the first and second embodiments.
The optical paths 1 and 2 are used as optical waveguides, and these optical waveguides are formed by a silica-based optical waveguide formed by using a flame hydrolysis deposition method and a photolithography process. Is not particularly limited and is appropriately set.

Furthermore, in each of the above embodiments, the first to Nth set wavelength bands are set to any of the S band, C band, and L band, but the first to Nth set wavelength bands are particularly The number of setting wavelength bands (the number of N), the range of setting wavelength bands, the combination, and the like are set as appropriate without being limited.

For example, at least one of the first to Nth set wavelength bands may be a band having a shorter wavelength than the S band, a band having a longer wavelength than the L band, or the C band (1530).
B band (153 to 153 nm) divided into two
0 nm to 1550 nm) as the first set wavelength band, and R
The band (1550 nm to 1570 nm) may be the second set wavelength band.

Further, in the optical wavelength multiplexer / demultiplexer of the present invention, the frequency spacing for multiplexing / demultiplexing by the narrow spacing optical wavelength multiplexing / demultiplexing circuit is not particularly limited, and is appropriately set. By appropriately setting the respective multiplexing / demultiplexing intervals by setting the multiplexing / demultiplexing interval of the wideband optical wavelength multiplexing / demultiplexing circuit to a wider value than the multiplexing / demultiplexing interval of the narrow spacing optical wavelength multiplexing / demultiplexing circuit, The same effect can be achieved.

Furthermore, the above-mentioned first and second embodiments show an example of combining a plurality of wavelengths of light, and the above-mentioned third to fifth embodiments show
Although an example of demultiplexing a plurality of wavelengths of light is shown, the optical wavelength multiplexer / demultiplexer 1 of the first and second embodiments can also be applied to demultiplexing of a plurality of wavelengths of light, and the third to fifth examples. The embodiment example can also be applied to multiplexing multiple wavelength lights.

[0149]

According to the present invention, the first to Nth (N is 2)
A plurality of narrow spacing optical wavelength multiplexing / demultiplexing circuits for multiplexing / demultiplexing light of each set wavelength band of the above integers) are provided.
A wideband optical wavelength multiplexing / demultiplexing circuit that combines the wavelengths of all wavelengths, including the set wavelength bands of, is formed on the substrate by forming an optical waveguide circuit on the substrate, so that light with narrow wavelength intervals can be spread over a wideband. A compact optical wavelength multiplexer / demultiplexer capable of multiplexing and demultiplexing, low loss, and excellent in mass productivity and cost reduction can be realized.

Further, according to the present invention, according to the structure in which the wavelength division wavelength of the wide band optical wavelength multiplexing / demultiplexing circuit is formed larger than the wavelength division wavelength division of the narrow spacing optical wavelength multiplexing / demultiplexing circuit, The multiplexer / demultiplexer can be reliably formed.

Furthermore, according to the present invention, according to the configuration in which two narrow spacing optical wavelength multiplexing / demultiplexing circuits are connected to one wideband optical wavelength multiplexing / demultiplexing circuit, light having narrow wavelength intervals of two set wavelength bands can be generated. It is possible to combine and demultiplex, low loss,
A compact optical wavelength multiplexer / demultiplexer with excellent mass productivity and low cost can be easily realized.

Further, according to the present invention, at least one narrow spacing optical wavelength multiplexing / demultiplexing circuit is formed by having one Mach-Zehnder optical interferometer circuit or a plurality of connected Mach-Zehnder optical interferometer circuits. In this case, the optical wavelength multiplexer / demultiplexer having the above effects can be more easily realized.

Further, in the present invention, according to the configuration in which at least one narrow spacing light wavelength multiplexing / demultiplexing circuit is formed to have the circuit of the arrayed waveguide diffraction grating, the light wavelength multiplexing / demultiplexing having the above effect can be obtained. A wavelength multiplexer can be easily realized, and an optical wavelength multiplexer / demultiplexer that operates well even if the wavelength spacing for multiplexing / demultiplexing is further narrowed can be realized.

Further, according to the present invention, the broadband optical wavelength multiplexing / demultiplexing circuit has one Mach-Zehnder interferometer circuit or a plurality of connected Mach-Zehnder interferometer circuits. An optical wavelength multiplexer / demultiplexer capable of playing can be realized more easily.

Further, in the present invention, the wideband optical wavelength multiplexer / demultiplexer circuit has an optical Fourier filter circuit formed by cascade-connecting two or more Mach-Zehnder optical interferometer circuits. Thus, when the lights of a plurality of wavelengths are combined, the light intensities of the respective wavelengths can be combined more uniformly.

[Brief description of drawings]

FIG. 1 is a main part configuration diagram showing a first embodiment of an optical wavelength multiplexer / demultiplexer according to the present invention in a plan view.

FIG. 2 is an explanatory plan view showing a configuration example of a Mach-Zehnder interferometer circuit.

FIG. 3 is an explanatory plan view showing a configuration of a broadband optical wavelength multiplexing / demultiplexing circuit applied to the optical wavelength multiplexing / demultiplexing device of the first embodiment.

FIG. 4 is a plan view illustrating the configuration of an optical Fourier filter.

FIG. 5 is a graph showing an insertion loss spectrum of a broadband optical wavelength multiplexing / demultiplexing circuit applied to the optical wavelength multiplexing / demultiplexing device of the first embodiment.

FIG. 6 is a graph showing an example of a combined light spectrum of the optical wavelength multiplexer / demultiplexer according to the first embodiment.

FIG. 7 is a main part configuration diagram showing a second embodiment of an optical wavelength multiplexer / demultiplexer according to the present invention by a plan view.

FIG. 8 is an explanatory diagram showing an optical Fourier filter circuit applied to a narrow spacing optical wavelength multiplexing / demultiplexing circuit of the optical wavelength multiplexing / demultiplexing device according to the second embodiment.

FIG. 9 is a graph showing an example of a combined light spectrum of the optical wavelength multiplexer / demultiplexer according to the second embodiment.

FIG. 10 is a main-part configuration diagram showing a third embodiment of the optical wavelength multiplexer / demultiplexer according to the present invention by a plan view.

FIG. 11 is an explanatory plan view showing a configuration example of a circuit of the arrayed waveguide diffraction grating together with its operation.

FIG. 12 is an explanatory plan view showing a configuration of a broadband optical wavelength multiplexing / demultiplexing circuit applied to the optical wavelength multiplexing / demultiplexing device according to the third embodiment.

FIG. 13 is a graph showing an example of a demultiplexed light spectrum of the optical wavelength multiplexer / demultiplexer according to the third embodiment.

FIG. 14 is a main part configuration diagram showing a fourth embodiment of the optical wavelength multiplexer / demultiplexer according to the present invention by a plan view.

FIG. 15 is a graph showing an example of a demultiplexed light spectrum of the optical wavelength multiplexer / demultiplexer according to the fourth embodiment.

FIG. 16 is a main-part configuration diagram showing a fifth embodiment of the optical wavelength multiplexer / demultiplexer according to the present invention by a plan view.

FIG. 17 is a graph showing an example of a demultiplexed light spectrum of the optical wavelength multiplexer / demultiplexer according to the fifth embodiment.

FIG. 18 is a main-part configuration diagram showing another embodiment of the optical wavelength multiplexer / demultiplexer according to the present invention by a plan view.

19 is a graph showing an insertion loss spectrum of the broadband optical wavelength multiplexing / demultiplexing circuit applied to the configuration example shown in FIG.

20 is a graph showing an example of a combined light spectrum in the configuration example shown in FIG.

FIG. 21 is an explanatory diagram showing a configuration example of a wavelength division multiplexing transmission system.

FIG. 22 is an explanatory diagram showing an example of a conventional optical wavelength multiplexing / demultiplexing device.

[Explanation of symbols]

1 Optical wavelength multiplexer / demultiplexer 7 Broadband optical wavelength multiplexer / demultiplexer circuit 8a, 8b, 8c Narrow spacing Optical wavelength multiplexer / demultiplexer circuit 9 Optical input unit 10 Optical output unit 20 Substrate 32 to 37, 38a to 40b, 60a to 63c Mach-Zehnder optical interferometer circuits 31, 48, 49, 56 to 59 Optical Fourier filter circuits 51 to 53 Array waveguide diffraction grating circuit

Claims (7)

[Claims] 1. A broadband optical wavelength multiplexing / demultiplexing circuit having a plurality of at least one of an optical input section and an optical output section, and a first to Nth circuit.
A plurality of narrow spacing optical wavelength multiplexing / demultiplexing circuits (N is an integer of 2 or more), and these narrow spacing optical wavelength multiplexing / demultiplexing circuits correspond to the optical signals corresponding to the broadband optical wavelength multiplexing / demultiplexing circuit. An optical waveguide circuit connected to the input section or the optical output section is formed on the substrate, and the first narrow spacing optical wavelength multiplexing / demultiplexing circuit multiplexes and demultiplexes wavelength light in a first set wavelength band, The second narrow spacing light wavelength multiplexing / demultiplexing circuit multiplexes / demultiplexes the wavelength light in the second setting wavelength band different from the first setting wavelength band. The multiplexing / demultiplexing circuit has a function of multiplexing / demultiplexing wavelength lights in the first to Nth setting wavelength bands, which are different from each other, and the broadband optical wavelength multiplexing / demultiplexing circuit has the first to Nth setting wavelength bands. The feature is that it has a function to combine and demultiplex the combined wavelength light of all wavelength bands. Optical wavelength demultiplexer to. 2. The optical wavelength according to claim 1, wherein the wavelength division multiplexing / demultiplexing circuit of the wide band optical wavelength multiplexing / demultiplexing circuit is formed larger than the wavelength division multiplexing / demultiplexing of the narrow spacing optical wavelength multiplexing / demultiplexing circuit. A multiplexer / demultiplexer. 3. The optical wavelength multiplexer / demultiplexer according to claim 1, wherein two narrow-spaced optical wavelength multiplexer / demultiplexer circuits are connected to one broadband optical wavelength multiplexer / demultiplexer circuit. 4. The at least one narrow spacing optical wavelength multiplexing / demultiplexing circuit is formed by having one Mach-Zehnder optical interferometer circuit or a plurality of connected Mach-Zehnder optical interferometer circuits, and the Mach-Zehnder optical interferometer circuit. Is a first optical waveguide, a second optical waveguide provided in parallel with the first optical waveguide, and the first optical waveguide and the second optical waveguide at positions spaced apart in the longitudinal direction of these optical waveguides. Of the delay circuit, the first optical waveguide and the second optical waveguide having two directional coupling portions formed by making the optical waveguides of the two adjacent to each other and a delay circuit sandwiched between the two directional coupling portions. 5. The optical wavelength multiplexer / demultiplexer according to claim 1, 2 or 3, wherein the lengths are different from each other. 5. The at least one narrow spacing light wavelength multiplexing / demultiplexing circuit is formed by including a circuit of an arrayed waveguide diffraction grating, and the circuit of the arrayed waveguide diffraction grating has at least one optical input. A waveguide, a first slab waveguide connected to the output end of the optical input waveguide, and a plurality of side-by-side connected lengths different in set amount from each other connected to the output end of the first slab waveguide. An arrayed waveguide including a channel waveguide, a second slab waveguide connected to an output end of the arrayed waveguide, and a plurality of optical output waveguides connected in parallel to an output end of the second slab waveguide 3. The method according to claim 1, further comprising:
The optical wavelength multiplexer / demultiplexer according to claim 4. 6. The broadband optical wavelength multiplexing / demultiplexing circuit is formed by having one Mach-Zehnder optical interferometer circuit or a plurality of Mach-Zehnder optical interferometer circuits connected to each other, and the Mach-Zehnder optical interferometer circuit has a first An optical waveguide, a second optical waveguide provided in parallel with the first optical waveguide, and the first optical waveguide and the second optical waveguide in proximity to each other at a position spaced apart in the longitudinal direction of these optical waveguides. And a delay circuit sandwiched between the two directional coupling portions, and the first optical waveguide and the second optical waveguide of the delay circuit are provided.
The optical wavelength multiplexer / demultiplexer according to any one of claims 1 to 5, wherein the optical waveguides are formed to have different lengths from each other. 7. The optical wavelength multiplexer / demultiplexer according to claim 6, wherein the broadband optical wavelength multiplexer / demultiplexer circuit has an optical Fourier filter circuit formed by cascading two or more Mach-Zehnder optical interferometer circuits. .