JP2003195068A - Array waveguide grating, array waveguide grating module, and optical communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an array waveguide grating which eliminate a need of adjustment of a signal before branching to reduce the number of parts and the insertion loss and to obtain an array waveguide grating module, and an optical communication system. <P>SOLUTION: First and second channel waveguides 102 and 103, a channel waveguide array 104, and first and second fan-shaped slab waveguides 105 and 106 are arranged on a substrate 101 of an array waveguide grating 100. Exponential function-shaped optical waveguides having shapes or sizes varied by channels are arranged in a second boundary part 109 on the exit side, which connects the second channel waveguide 103 and the second fan-shaped slab waveguide 106, and optical frequency characteristics are changed or corrected in accordance with signal light of each of channels after branching. Thus adjustment of the level of signal light of each channel is made unnecessary or is reduced, and the insertion loss is reduced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arrayed-waveguide grating as an optical wavelength multiplexer / demultiplexer used in optical communication, an arrayed-waveguide grating module using the same, an optical communication device and an optical communication system, and more particularly to an array. The present invention relates to an arrayed waveguide grating in which an optical function is added to the original function as a waveguided grating, an arrayed waveguide grating module using the same, an optical communication device, and an optical communication system.

[0002]

2. Description of the Related Art The demand for large-capacity information transmission has been increasing with the continuous connection of the Internet and the increase in the capacity of communication data. In the optical communication system that uses signal light,
Improving the wavelength multiplicity is extremely important when carrying out large-capacity information transmission. In this respect, the role of the arrayed waveguide grating as a multiplexing / demultiplexing element that multiplexes or splits the optical wavelengths is important and is considered to be one of the key devices. The arrayed waveguide grating has a passive structure and has a narrow transmission width of a light wavelength and a high extinction ratio. Further, there is a feature that a large number of signal lights can be multiplexed / demultiplexed according to the number of waveguides.

In such an arrayed-waveguide grating, it is desirable that the output level or loss level of the signal light of the laser light source does not change suddenly even if the signal light of the laser light source fluctuates from the center optical frequency of each optical waveguide. Further, when the arrayed waveguide gratings are connected in multiple stages, the modulation component of the signal light is cut except in the band where each arrayed waveguide grating transmits the signal light in common. Therefore, it is important to realize a transmission characteristic having a flat peak level with respect to the optical frequency in the sense of increasing the transmission efficiency of signal light.

FIG. 15 shows that such a peak level is flat.
Arrayed Waveguide Proposed to Realize High Transmission Characteristics
It is an example of a road grid. JP-A-9-2972
In this proposal disclosed in Japanese Patent No. 28, the array waveguide case is disclosed.
On the substrate 11 that constitutes the child 10, one or more first
Channel waveguide (input channel waveguide) 12 and a plurality of
Second channel waveguide (output channel waveguide) 13
And a channel bent in a certain direction with different curvatures.
Channel waveguide array 14 and the first channel waveguide 12
First fan-shaped slab conductor for connecting the channel waveguide array 14
The waveguide 15, the channel waveguide array 14, and the second channel
The second fan-shaped slab waveguide 16 for connecting the optical waveguide 13
It is arranged. Incident from the first channel waveguide 12
Wavelength λ ₁, Λ₂, …… λ_nThe multiple signal light of the first fan-shaped
The path is widened by the slab waveguide 15,
The light enters the waveguide array 14.

In the channel waveguide array 14, a constant optical path length difference (waveguide length difference) ΔL is provided between the arrayed waveguides constituting the channel waveguide array 14, and the optical path length is sequentially increased by the waveguide length difference ΔL. , Or is set to be shorter.
Therefore, the light guided through each arrayed waveguide reaches the second fan-shaped slab waveguide 16 with a phase difference at regular intervals. In reality, since there is chromatic dispersion, the equiphase surface is inclined depending on the wavelength. As a result, the second fan-shaped slab waveguide 16 and the second
Light is imaged (focused) at different positions on the interface of the channel waveguide 13. Second at each position corresponding to the wavelength
, The arbitrary wavelength components λ ₁ , λ ₂ , ... From the _second channel waveguide 13 are arranged.
It is possible to take out λ _n individually.

FIG. 16 is an enlarged view of each boundary portion between the incident side and the output side of the first fan-shaped slab waveguide of the arrayed waveguide grating shown in FIG. Parabolic optical waveguides 21 are arranged at the boundaries between the first channel waveguides 12 and the first fan-shaped slab waveguides 15, respectively. At the boundary between the first fan-shaped slab waveguide 15 and the channel waveguide array 14, tapered optical waveguides 22 that are linearly spread as viewed from the respective channel waveguide array 14 sides are arranged.

The light incident on the first fan-shaped slab waveguide 15 forms a parallel beam-like light distribution when passing through the parabolic optical waveguide 21. Then, a spatially flat electric field distribution is generated at the boundary with the first fan-shaped slab waveguide 15. The light having the flat field distribution obtained in this manner spreads laterally in the first fan-shaped slab waveguide 15 and travels. Then, each of the waveguides constituting the channel waveguide array 14 shown in FIG. 15 is excited, and the second sector slab waveguide 16 collects the light at a position corresponding to the optical frequency f in the second channel waveguide 13. It will shine.

At the time of this focusing, the second fan-shaped slab waveguide 16 and the second channel waveguide 13 are formed by the reciprocity theorem.
The light distribution at the boundary with the first fan-shaped slab waveguide 15
The light distribution is flat as in the boundary between the first and second channel waveguides 12.

FIG. 17 is an enlarged view of each boundary portion between the incident side and the output side of the second fan-shaped slab waveguide of the proposed arrayed waveguide grating. The second channel waveguides 13 are formed at the boundary between the second channel slab waveguide 16 and the second sector slab waveguide 16 and at the boundary between the second sector slab waveguide 16 and the channel waveguide array 14, respectively. Alternatively, the tapered optical waveguides 23 and 24 that are linearly spread when viewed from the channel waveguide array 14 side are arranged. The opening widths of the optical waveguides 23 and 24 are designed to be narrower than the width of the flat field distribution described above. Therefore, even if the optical frequency f of the light source (not shown) is changed to some extent, the amount of light coupled to the second channel waveguide 13 on the output side is substantially constant. Accordingly, it is possible to realize a flat optical frequency characteristic in which the demultiplexing output is substantially constant even if the optical frequency f of the light source changes.

FIG. 18 shows a structure of an arrayed waveguide grating according to another conventional proposal. JP-A-10-1
According to this proposal disclosed in Japanese Patent No. 97735, three parabolic-shaped openings having different sizes are formed at the boundary between the input-side (first) channel waveguide 31 and the input-side first slab waveguide 32. The parts 33 _{1 to} 33 ₃ are arranged. The openings 36 _{1 to} 36 _n arranged at the boundary between the channel waveguide array 34 and the first slab waveguide 32 have a tapered shape as shown in FIG.

[0011] In the proposed shown in FIG. 18, once the level of the signal light for all the channels output by either inputting the multiplexed signal light using any of the three openings 33 _to 333 parabolic And can be adjusted.

By the way generally the wavelength lambda _1, lambda _2, ...... even lambda _n multiplexed signal light signal level of is constant irrespective of the wavelength, all wavelengths in the amplifying means which optical fiber amplifiers such as the signal light When the signals are collectively amplified, a high signal level and a low signal level are generated depending on the wavelength. In order to eliminate such an uneven signal level, the signal light that has passed through an optical device such as an arrayed-waveguide grating and has been separated for each wavelength has been input to a gain equalizer, and the level for each channel has been eliminated. The difference is being reduced.

FIG. 19 shows a configuration of a receiving side device of a conventional optical communication system. The amplifier 42 provided on the input side of the receiving side device 41 shown in this figure includes a transmission line 43
The multiplexed signal light 44 transmitted through is input and amplified. The multiplexed signal light 45 after amplification is an AWG (arrayed wavegu
ide: waveguide grating) 46. The AWG46
Similarly to the arrayed-waveguide grating 10 shown in FIG. 15, the multiplexed signal light composed of the signal light of a plurality of channels input is transmitted by the wavelength λ ₁
Demultiplexed to signal light of ~ λ _N.

By the way, as already described,
The amplifier 42 that amplifies the light 44 generally has a frequency
It does not necessarily have a flat amplification characteristic.
Yes. Therefore, the output of the amplifier 42 after the amplification is changed to the AWG 46.
To the optical receiver 47.
Input the signal light of each channel to
There is a case where the signal level greatly differs for each
However, good reception characteristics cannot be obtained. There
Conventionally, the wavelength λ demultiplexed and output from the AWG 46 ₁~
λ_NThe signal light of the
50₁~ 50_NConfiguration for inputting to the optical receiver 47 via the
It was.

[0015]

[SUMMARY OF THE INVENTION However, in the receiving device 41 having such a configuration, since the attenuator 50 ₁ to 50 _N is required for each channel (wavelength), the number of parts is greatly increased. Here, the receiving side device 41 is shown, but the transmitting side device also requires an attenuator for each channel. That is, even in the transmitting side device that multiplexes the signal light of each wavelength and sends out, the output characteristics of the amplifier provided for transmission are different for each channel (wavelength). Therefore, in order to make the signals of the respective channels forming the multiplexed signal light passing through the amplifier on the transmission side have substantially the same level, A
It was necessary to arrange an attenuator for each channel in front of the multiplexer comprising the WG to adjust the signal level.

As described above, conventionally, in order to configure the optical communication system, the attenuator is separately required for each channel on both the transmitting side and the receiving side. Therefore, the cost of the optical communication system increases as the number of channels increases. There was a problem that was up.

Therefore, an object of the present invention is to make it possible to reduce the number of components and the insertion loss by eliminating the level adjustment of signals before demultiplexing or multiplexing, an arrayed waveguide grating, an arrayed waveguide grating module, and optical communication. To provide a system.

[0018]

An arrayed-waveguide grating according to a first aspect of the present invention comprises: (a) a predetermined substrate; and (b) an input side and an output for propagating a light wave arranged on this substrate. Side channel waveguides, (c) a channel waveguide array configured such that the lengths of adjacent waveguides are sequentially lengthened by a predetermined difference, and (d) one end of the input side channel waveguides and channel guides. A first slab waveguide that connects one end of the waveguide array via a waveguide portion having a first shape; and (e) one end of the channel waveguide on the output side formed on the substrate and the other channel waveguide array. A second slab waveguide that connects the end to the second shape waveguide portion, and (e) an opening of each channel that constitutes a channel waveguide on the output side with respect to the second slab waveguide. The shape and size of the parts remains at least part of them. It is characterized in that is different from the openings.

That is, according to the first aspect of the invention, before the demultiplexed signal light is propagated for each channel in the second channel waveguide, the second slab waveguide and the output-side channel waveguide are connected. The shape or size of the opening of each channel that makes up a part may be made different for each channel as needed, so that adjustment of characteristics such as the level of signal light after demultiplexing becomes unnecessary. , Or reduce it. It is also possible to reduce insertion loss. Not only the shapes of the openings may be different, but the same shape may be different in size.

According to a second aspect of the invention, in the arrayed-waveguide grating according to the first aspect, the shape of the opening of each channel forming the second channel waveguide is tapered, and the optical waveguide width at the taper end is formed. It is characterized in that the length of Wt or the taper is different from that of the remaining openings in at least a part of the channel.

That is, the invention according to claim 2 shows a case where the shape of the opening of each channel forming the second channel waveguide is changed by using the taper shape.

According to a third aspect of the present invention, in the arrayed-waveguide grating according to the first aspect, the shape and size of the opening of each channel forming the second channel waveguide is such that the traveling direction of the light wave is X, When Wp is the terminal width at the connection point with the slab waveguide, Wc is the width of the waveguide portion in the direction orthogonal to the traveling direction X of the light wave, and a is a parameter giving the shape of the exponential function, W (X) = (Wp-Wc) * (1-exp (-a *
X)) + Wc and is characterized in that at least some of these parameters are different for at least some channels and the rest of the channels.

That is, the invention according to claim 3 shows a case where the shape of the opening of each channel forming the second channel waveguide is changed by using the shape of the exponential function.

According to a fourth aspect of the present invention, in the arrayed-waveguide grating according to the first aspect, the shape and size of the opening of each channel forming the second channel waveguide is a parabolic shape and its size. Is characterized by.

That is, the invention according to claim 4 shows a case where the shape of the opening of each channel constituting the second channel waveguide is changed by using the parabola shape or its size.

According to a fifth aspect of the present invention, in the arrayed-waveguide grating according to the first aspect, the shape and size of the opening of each channel forming the second channel waveguide is tapered and its size, and the propagation of light waves. When the direction is X, the terminal width at the connection point with the slab waveguide is Wp, the spread of the waveguide portion in the direction orthogonal to the light wave traveling direction X is Wc, and the parameter giving the shape of the exponential function is a , W (X) = (Wp-Wc) * (1-exp (-a *
X)) + Wc The shape and its size represented by the formula or a parabolic shape and a plurality of sizes thereof are combined.

That is, according to the fifth aspect of the present invention, by combining a plurality of tapered shapes, exponential shapes or parabolic shapes represented by the above formulas and sizes thereof, each channel constituting the second channel waveguide is combined. It indicates that the shape and size of the opening may be set.

According to a sixth aspect of the invention, in the arrayed-waveguide grating according to the fifth aspect, the shape and size obtained by combining the plurality are different from each other in the traveling direction of the signal light of the corresponding channel. It is characterized by being a combination of.

That is, the invention according to claim 6 indicates that the combination of the various shapes and sizes described above is performed in the traveling direction of the signal light of the corresponding channel. For example, the shape is an exponential function halfway and the parabolic shape after that.

According to a seventh aspect of the present invention, in the arrayed waveguide grating according to the fifth aspect, different kinds of shapes and sizes are selected for different channels as the combined shape and size. It is characterized by being a thing.

That is, in the invention described in claim 7, the combination of the various shapes and sizes described above is a combination between channels. For example, some channels are exponentially shaped, other channels are parabolic shaped, and so on.

According to an eighth aspect of the present invention, in the arrayed waveguide grating according to the first aspect, the first slab waveguide is provided with the first waveguide.
The shape and size of the openings of each channel constituting the channel waveguide are characterized in that at least some of them are different from the remaining openings.

That is, according to the invention of claim 8, the shape or size of the openings of the respective channels forming the connection portion of the second slab waveguide and the second channel waveguide is changed, and at the same time, the first slab waveguide is simultaneously changed. It is shown that the shape and size of the opening of each channel forming the first channel waveguide with respect to the slab waveguide of 1) may be changed. When the signal light is input in the opposite direction of the arrayed-waveguide grating, not only the difference in the shape and size of the opening of each channel forming the first channel waveguide is effective, but also in this case, the second channel is formed. There is an advantage that the input level of the multiplexed light can be collectively adjusted by selecting a desired shape and size from the plurality of openings of the waveguide.

According to a ninth aspect of the present invention, in the arrayed-waveguide grating according to the eighth aspect, the shape of the opening of each channel forming the first channel waveguide is tapered, and the optical waveguide width at the taper end is formed. It is characterized in that the length of Wt or the taper is different from that of the remaining openings in at least a part of the channel.

That is, the invention according to claim 9 shows the case where the shape of the opening of each channel constituting the first channel waveguide is changed by using the tapered shape.

According to a tenth aspect of the present invention, in the arrayed-waveguide grating according to the eighth aspect, the shape and size of the opening of each channel forming the first channel waveguide are such that the traveling direction of the light wave is X, When Wp is the terminal width at the connection point with the slab waveguide, Wc is the width of the waveguide portion in the direction orthogonal to the traveling direction X of the light wave, and a is a parameter giving the shape of the exponential function, W (X) = (Wp-Wc) * (1-exp (-a *
X)) + Wc and is characterized in that at least some of these parameters are different for at least some channels and the rest of the channels.

That is, the tenth aspect of the present invention shows the case where the shape of the opening of each channel constituting the first channel waveguide is changed by using the shape of the exponential function.

According to an eleventh aspect of the invention, in the arrayed-waveguide grating according to the eighth aspect, the shape and size of the opening of each channel constituting the first channel waveguide is a parabolic shape and its size. Is characterized by.

That is, the invention according to claim 11 shows the case where the shape of the opening of each channel constituting the first channel waveguide is changed by using the parabola shape or its size.

According to a twelfth aspect of the present invention, in the arrayed-waveguide grating according to the eighth aspect, the shape and size of the opening of each channel forming the first channel waveguide is tapered and its size, and Let X be the traveling direction, Wp be the terminal width at the connection point with the slab waveguide, and X be the traveling direction of the light wave.
When Wc is the spread of the waveguide portion in the direction orthogonal to and the parameter giving the shape of the exponential function is a, W (X) = (Wp-Wc) * (1-exp (-a *
X)) + Wc, which is a combination of a plurality of shapes and sizes thereof, a parabola shape and sizes thereof.

That is, according to the twelfth aspect of the present invention, by combining a plurality of tapered shapes, exponential shapes or parabolic shapes represented by the above equations, and their sizes,
It indicates that the shape and size of the opening of each channel forming the first channel waveguide may be set.

According to a thirteenth aspect of the present invention, in the arrayed-waveguide grating according to the twelfth aspect, the shapes and sizes obtained by combining the plurality are different from each other in the traveling direction of the signal light of the corresponding channel. It is characterized by being a combination of.

That is, the invention according to claim 13 indicates that the combination of the various shapes and sizes described above is performed in the traveling direction of the signal light of the corresponding channel. For example, the shape is an exponential function halfway and the parabolic shape after that.

According to a fourteenth aspect of the present invention, in the arrayed waveguide grating according to the twelfth aspect, different shapes and sizes are selected for different channels as the combined shape and size. It is characterized by being a thing.

That is, in the fourteenth aspect of the present invention, the combination of various shapes and sizes described above is a combination between channels. For example, some channels are exponentially shaped, other channels are parabolic shaped, and so on.

In the arrayed waveguide grating module of the fifteenth aspect of the present invention, (a) a predetermined substrate, first and second channel waveguides arranged on the substrate for propagating light waves, and adjacent to each other A channel waveguide array configured such that the lengths of the waveguides to be sequentially lengthened by a predetermined difference, and one end of the first channel waveguide and one end of the channel waveguide array have a first-shaped waveguide portion. A first slab waveguide connected to the first slab waveguide, and one end of the second channel waveguide formed on the substrate and the other end of the channel waveguide array connected to each other via the second shaped waveguide portion. An array waveguide element having two slab waveguides; (b) a fiber array optically coupled to the waveguide element; and (c) a case for housing the array waveguide element and the fiber array. , (D) Second slab waveguide The shape and size of the opening of each channel constituting the second channel waveguide at least some of them are characterized by being different from the remaining openings against.

That is, the invention of claim 15 shows an arrayed waveguide grating module in which a fiber array and a case accommodating the fiber array are connected to the arrayed waveguide grating according to the invention of claim 1 as a minimum structure. ing. It is free to add other circuit components such as temperature control circuits.

According to a sixteenth aspect of the present invention, in the arrayed-waveguide grating module according to the fifteenth aspect, the shape and size of the opening of each channel constituting the first channel waveguide with respect to the first slab waveguide are different. Is characterized in that at least part of it is different from the rest of the openings.

That is, according to the sixteenth aspect of the present invention, similarly to the eighth aspect of the present invention, the shape and size of the opening of each channel constituting the first channel waveguide is different for each channel or each waveguide. It indicates that

According to a seventeenth aspect of the invention, there is provided the arrayed waveguide grating module according to the fifteenth or sixteenth aspect,
The opening of each channel is tapered, and the optical waveguide width Wt at the taper end or the length of the taper is different from the remaining openings in at least a part of the channel.

That is, the seventeenth aspect of the present invention shows an arrayed waveguide grating module in which the taper parameter is changed.

In the eighteenth aspect of the present invention, the arrayed waveguide grating module of the fifteenth or sixteenth aspect,
The shape and size of the opening of each channel are such that the traveling direction of the light wave is X, the terminal width at the connection point with the slab waveguide is Wp, and the spread of the waveguide portion in the direction orthogonal to the traveling direction X of the light wave is Wc. And a is a parameter giving the shape of the exponential function, W (X) = (Wp-Wc) * (1-exp (-a *
X)) + Wc and is characterized in that at least some of these parameters are different for at least some channels and the rest of the channels.

That is, the eighteenth aspect of the present invention shows an arrayed-waveguide grating module in which the parameter for the exponential function is changed.

According to a nineteenth aspect of the invention, there is provided an arrayed waveguide grating module according to the fifteenth or sixteenth aspect,
The shape and size of the opening of each channel is characterized by a parabolic shape and its size.

That is, the nineteenth aspect of the present invention shows an arrayed waveguide grating module in which the parabolic shape and its size are changed.

According to a twentieth aspect of the invention, there is provided the arrayed waveguide grating module according to the fifteenth or sixteenth aspect,
The shape and size of the opening of each channel is tapered and its size, the traveling direction of the light wave is X, the termination width at the connection point with the slab waveguide is Wp, and the waveguide is in a direction orthogonal to the traveling direction X of the light wave. When the spread of the portion is Wc and the parameter giving the shape of the exponential function is a, W (X) = (Wp-Wc) * (1-exp (-a *
X)) + Wc The shape and its size represented by the formula or a parabolic shape and a plurality of sizes thereof are combined.

That is, the invention according to claim 20 shows an arrayed waveguide grating module using the arrayed waveguide grating according to claim 5.

According to a twenty-first aspect of the present invention, in the arrayed-waveguide grating module according to the twentieth aspect, the shape and size obtained by combining the plurality are different from each other in the traveling direction of the signal light of the corresponding channel. It is characterized by a combination of sizes.

That is, the twenty-first aspect of the invention shows an arrayed-waveguide grating module using the arrayed-waveguide grating of the sixth aspect.

According to a twenty-second aspect of the present invention, in the arrayed-waveguide grating module according to the twentieth aspect, different types of shapes and sizes are selected for different channels for the combined shape and size. It is characterized by being

That is, the invention of claim 22 shows an arrayed waveguide grating module using the arrayed waveguide grating of claim 7.

In the optical communication system according to claim 23,
(B) Each of the transmission lines that transmit the wavelength-division-multiplexed signal light is connected by a node, and each node separates the wavelength-division-multiplexed signal light into the signal light of each wavelength; Equipped with an arrayed waveguide grating that wavelength-division-multiplexes the signal light separated into the signal light of the wavelength,
(B) At least one of these arrayed waveguide gratings is
A predetermined substrate, first and second channel waveguides arranged on the substrate for propagating light waves, and a channel configured such that the lengths of adjacent waveguides are sequentially lengthened by a predetermined difference. A waveguide array, a first slab waveguide connecting one end of the first channel waveguide and one end of the channel waveguide array, one end of a second channel waveguide formed on the substrate, and the channel waveguide array A second slab waveguide connected to the other end of the second slab waveguide for demultiplexing the wavelength-multiplexed light that has passed through the channel waveguide array, and (c) a second channel waveguide for the second slab waveguide. The shape and size of the openings of each of the channels is characterized in that at least some of them differ from the rest of the openings.

That is, the invention of claim 23 shows an optical communication system using the arrayed waveguide grating as the invention of claim 1. Each arrayed-waveguide grating has the function of compensating or changing the characteristics of the signal light, reducing the number of attenuators and gain equalizers overall, simplifying the system configuration and improving reliability. Can be planned. Further, it is possible to reduce the insertion loss at the location of the arrayed waveguide grating.

In the arrayed waveguide grating according to claim 24,
The arrayed waveguide grating according to claim 1 is characterized in that the arrangement intervals of the openings of the respective channels forming the second channel waveguide with respect to the second slab waveguide are unequal wavelength intervals.

That is, according to the twenty-fourth aspect of the invention, the unequal wavelength intervals are effective in preventing new light wave crosstalk caused by mixing of the output signal lights.

According to a twenty-fifth aspect of the present invention, in the arrayed-waveguide grating module according to the fifteenth aspect, the arrangement interval of the openings of the respective channels forming the second channel waveguide with respect to the second slab waveguide is different. It is characterized in that they have equal wavelength intervals.

That is, in the twenty-fifth aspect of the invention, the invention of the twenty-fourth aspect is applied to an arrayed waveguide grating module. As a result, the same effect as that of the invention of claim 24 can be obtained.

According to a twenty-sixth aspect of the invention, in the optical communication system according to the twenty-third aspect, the arrangement intervals of the openings of the respective channels constituting the second channel waveguide with respect to the second slab waveguide are unequal wavelengths. It is characterized by intervals.

That is, in the invention described in claim 26, the invention described in claim 24 is applied to an optical communication system. As a result, the same effect as that of the invention of claim 24 can be obtained.

[0070]

DETAILED DESCRIPTION OF THE INVENTION

[0071]

EXAMPLES The present invention will be described in detail below with reference to examples. <First embodiment>

FIG. 1 shows the structure of an arrayed waveguide grating in the first embodiment of the present invention. On the substrate 101 constituting the arrayed waveguide grating 100, one or a plurality of first channel waveguides 102 and a plurality of second channel waveguides 103, and channel guides each having a different curvature and curved in a certain direction. A waveguide array 104, a first fan-shaped slab waveguide 105 connecting the first channel waveguide 102 and the channel waveguide array 104, and a second sector slab waveguide 105 connecting the channel waveguide array 104 and the second channel waveguide 103. The fan-shaped slab waveguide 106 is arranged.
The wavelength λ ₁ incident from the first channel waveguide 102,
The multiple signal light of λ ₂ , ..., λ _n has its path widened by the first fan-shaped slab waveguide 105 and enters the channel waveguide array 104.

In the channel waveguide array 104, a constant optical path length difference (waveguide length difference) ΔL is provided between the arrayed waveguides constituting the channel waveguide array 104, so that the optical path length becomes longer or shorter sequentially. It is set. Therefore, the light guided through the arrayed waveguides reaches the second fan-shaped slab waveguide 106 with a phase difference of a constant interval. In reality, there is chromatic dispersion, so
The equiphase surface is tilted depending on the wavelength. As a result, light is imaged (focused) at different positions on the interface between the second fan-shaped slab waveguide 106 and the second channel waveguide 103 composed of a plurality of waveguides depending on the wavelength. Since the second channel waveguides 103 are arranged at respective positions corresponding to the wavelengths, arbitrary wavelength components λ ₁ , λ ₂ , ... λ _n can be individually taken out from the second channel waveguides 103. Will be possible.

In the arrayed waveguide grating 100 of this embodiment,
Channel waveguides 102 and 103 and fan-shaped slab waveguide 10
Of the first boundary portion 108 and the second boundary portion 109 serving as a connecting portion of 5, 106, particularly the second boundary portion 10
9 has a characteristic. That is, the shape or size of the exponential function-shaped optical waveguide 112 is not the same for all of the channel waveguides 103, so that the attenuation rate of the signal level can be adjusted for each channel. This will be specifically described later.

Next, a specific structure of the arrayed waveguide grating 100 of this embodiment will be described. In this embodiment, a semiconductor (silicon) substrate is used as the substrate 101. of course,
The substrate 101 is not limited to the semiconductor. The substrate 101 of the present embodiment uses a quartz-based material in which phosphorus, germanium, titanium, boron, fluorine, etc. are added to the lower clad layer, and the flame deposition method and atmospheric pressure CVD (Chemical Vapor Deposit) are used.
ion: chemical vapor deposition) method, sputtering method, spin coating method, electron beam evaporation method, etc.
It is deposited with a thickness of (micron meter). On top of this,
An optical waveguide-shaped core layer of quartz doped with impurities to have a refractive index higher than that of the lower clad layer is deposited to a thickness of about 3 to 8 μm. The optical waveguide shape of this core layer will be described later.

Photolithography is used to manufacture the core layer, and the fine regions are transferred to an appropriate mask material. Subsequently, reactive ion etching (RIE: Reactive Ion Etchin
g) Equipment and reactive ion beam etching (RIBE: R
An unnecessary area is removed by a dry etching method such as eactive ion beam etching. Finally, the above-mentioned quartz material whose refractive index is set lower than that of the core layer is used again to deposit an upper clad layer having a thickness of several tens of μm.

FIG. 2 shows the first channel waveguide and the first channel waveguide of FIG.
1 The shape of the core at the boundary of the fan-shaped slab waveguide is
It is shown. However, for convenience of illustration, here
The first channel waveguide 102 shown in FIG.
First channel waveguide 102 ₁-10₃Three channels
It is assumed that it is configured by a waveguide. First
-Third first channel waveguide 102₁-10₃That of
Each of the first to third tapes has a corresponding taper shape.
PA-shaped optical waveguide 111₁~ 111₃1st fan-shaped through
It is connected to the Love waveguide 105.

FIG. 3 shows the shape of the core at the boundary between the second channel waveguide and the second fan-shaped slab waveguide shown in FIG. Also in this figure, for convenience of illustration, it is assumed that the second channel waveguide 103 shown in FIG. 1 is composed of three channel waveguides, that is, first to third second channel waveguides 103 _{1 to} 103 _3. There is. First to third
Of the second channel waveguides 103 _{1 to} 103 ₃ through the second fan-shaped slab waveguides via the _first to third exponential function-shaped optical waveguides 112 _{1 to} 112 ₃ having a corresponding exponential function shape. It is connected to 106.

The core shape at the boundary between the first fan-shaped slab waveguide 105 and the channel waveguide array 104 and at the boundary between the channel waveguide array 104 and the second fan-shaped slab waveguide 106 shown in FIG. As shown in FIG. 2, both are tapered. However, the shapes of these portions do not directly affect the optical frequency characteristics, and are not the subject of consideration of the present invention. Therefore, the optical frequency characteristic at the first boundary portion 108 and the second boundary portion 109, that is, the optical frequency characteristic due to the shape of the optical waveguide at the connecting portion between the channel waveguides 102 and 103 and the fan-shaped slab waveguides 105 and 106 is shown. I will consider it.

In the arrayed-waveguide grating 100 having the structure shown in FIGS. 1 to 3, the light incident on a predetermined one of the first channel waveguides 102 is generated by the light shown in FIG.
When passing through the tapered optical waveguide 111 having the tapered shape shown in FIG. The spread of the field distribution is determined by the optical waveguide width Wt at the taper end as shown in FIG.

Light having such a field distribution propagates laterally in the first fan-shaped slab waveguide 105 and excites the respective waveguides forming the channel waveguide array 104.
Then, the light is focused on the second fan-shaped slab waveguide 106 at a position corresponding to the optical frequency f of the second channel waveguide 103. At the time of this light collection, due to the reciprocity theorem, the light distribution at the boundary between the second fan-shaped slab waveguide 106 and the second channel waveguide 103 is also the first fan-shaped slab waveguide 105 and the first channel waveguide. The light distribution is flat as in the boundary portion with 102.

By the way, as shown in FIG. 3, the second channel waveguide 103 and the second fan-shaped slab waveguide 1 of this embodiment are used.
The length of the boundary portion of 06 is L as a shape other than the tapered shape.
₁ , L ₂ , L ₃ ... Exponential function-shaped optical waveguides 112 ₁ , 11
2 ₂ , 112 ₃ , ... Are arranged. These exponential shape optical waveguide 112 _1, 112 _2, 112 _3, ... of the core opening width Wp _1, Wp _2, Wp _3, ... is 1-5 times greater than the width of the Gaussian distribution which has already been described Is designed to be. Thus, even if the optical frequency f of the light source changes, the amount of light coupled to the second channel waveguide 103 becomes almost constant. Therefore, it is possible to realize a flat optical frequency characteristic such that the demultiplexing output is substantially constant even if the optical frequency f of the light source changes.

FIG. 4 shows one of the exponential function-shaped optical waveguides shown in FIG. Exponential function optical waveguide 1
12 _{1 to} 112 ₃ are determined by the optical waveguide shape having the length L ₂ given by the optical waveguide width W (X) represented by the following formula (1). Here, the code | symbol X has shown the advancing direction of a light wave. The symbol a is a shape variable that gives the shape of an exponential function, and the symbol Wc represents the core width of the channel waveguide 103. Further, the symbol Wp represents the termination width at which the exponential function-shaped optical waveguide 112 is connected to the second fan-shaped slab waveguide 106 as shown in FIG.

[0084]   W (X) = (Wp-Wc) * (1-exp (-a * X)) + Wc                                                             …… (1)

In this embodiment, the parameters of the exponential function shape of the exponential function optical waveguide 112 connected to the second channel waveguide 103 are appropriately corrected corresponding to the demultiplexed signal lights of the respective optical frequencies f. I have decided. Then, different transmitted light frequency characteristics are realized for each wavelength or each channel.

Incidentally, as shown in FIG. 15, in the conventional arrayed waveguide grating that realizes the flat transmission characteristic,
On the boundary side of the first fan-shaped slab waveguide located on the input side of signal light, an optical waveguide having a shape other than the tapered shape (parabolic shape in this example) is arranged as shown in FIG. The tapered optical waveguide is arranged on the boundary side of the second fan-shaped slab waveguide located on the output side. In such a conventional arrangement that is the reverse of the arrayed-waveguide grating 100 of the present embodiment, the termination width (parabola width) Wp is set for each channel.
And the symbol a are common, and only the taper width Wt can be individually set. For this reason, when it is desired to change the characteristics on a channel-by-channel basis, only the taper width Wt needs to be changed to change the setting, so the degree of freedom in design is low.

On the other hand, in the arrayed waveguide grating shown in FIG. 1 of this embodiment, the first waveguide located on the input side of the multiplexed signal light is used.
Of the tapered optical waveguide 111 _{1-111 3} as shown in FIG. 2 are arranged in a boundary portion 108 side, the second boundary portion 109 side which is positioned on the output side which demultiplexes the multiplexed signal light other than tapered An exponential-shaped optical waveguide 112 having an exponential shape is arranged as a shape. Therefore, for each optical frequency, the taper width Wt on the input side is common, while the terminal width (parabola width) Wp can be individually set on the output side.
Further, the symbol a can be individually set. Therefore, the degree of freedom in design is increased when the characteristics are changed for each channel. For this reason, detailed adjustment of the transmitted light frequency characteristic with respect to the optical frequency f is performed by using these exponential-shaped optical waveguides 1.
It will be possible to do at 12.

In the present invention, the second unit located on the output side
It is not forbidden to dispose a tapered optical waveguide on the boundary portion 109 side. Even in the case of a tapered optical waveguide, by changing the optical waveguide width Wt at the taper end or the taper length for each channel of the second channel waveguide 103, the characteristics of the signal light of each channel after demultiplexing can be obtained. This is because they can be set individually. However, in this embodiment, the exponential-shaped optical waveguide 11 having an exponential-shaped shape is selected so that the characteristics can be selected and set in a wider range.
I am using 2.

FIG. 5 specifically shows the boundary portion between the second channel waveguide and the second fan-shaped slab waveguide shown in FIG. In this embodiment, the shape of the exponential function-shaped optical waveguides 112 _{1 to} 112 ₅ is different for each channel. In this example, the symbol a is changed in four ways in total for the five _{first to fifth} second channel waveguides 103 _{1 to} 103 ₅ . By changing the symbol a in this manner, the core opening width Wp is constant, but the lengths L _{1 to} L _{4 of} the exponential function-shaped optical waveguide 112 are changed.

In this way, by making the shapes of the exponential function-shaped optical waveguides 112 _{1 to} 112 ₅ of each channel different,
With respect to the signal light of each channel multiplexed and input to the channel waveguide 102 shown in FIG. 1, the signal level and the flatness output from the _first to n-th second channel waveguides 103 _{1 to} 103 _n Can be adjusted appropriately. This allows
It is possible to appropriately omit or simplify the attenuator that has been conventionally added after the arrayed waveguide grating 100. For example, two types of attenuators each channel waveguide 103 ₁ 10 @ 2 to 10 @ 3 _n for fine adjustment and the coarse adjustment
In the arrayed-waveguide grating module or the optical communication system which has been arranged in the above, the attenuator for coarse adjustment can be omitted, and the cost reduction and the miniaturization of the parts can be achieved by reducing the number of parts. In addition, the reduction in the number of parts is also effective in reducing the insertion loss.

<Modification of First Embodiment>

FIG. 6 shows an essential part of a boundary portion between the second channel waveguide and the second fan-shaped slab waveguide in the modification of the first embodiment of the present invention. 6, the same parts as those in FIG. 3 are designated by the same reference numerals, and the description thereof will be appropriately omitted.

In this modification, the array waveguide of the previous embodiment is used.
The road grid 100 is attached to a particular channel or channels.
While adding the same function as adding a noether,
Not only attenuator but also unequal wavelength spacing
Of. The second boundary portion 109 has first to third fingers.
Numerical function shape optical waveguide 212₁~ 212₃Is located
It Of these, the second exponential function-shaped optical waveguide 212₂Is the
First and third exponential shaped optical waveguides 212₁, 212₃
The length L of the exponential-shaped optical waveguide shown in FIG.
₂Is getting shorter. In addition, the third exponential shaped optical waveguide
Road 212₃Is the first and second exponential shaped optical waveguides 2
12₁, 212₂End width Wp₁, Wp₂Exponential compared to
The shape optical waveguide is connected to the second fan-shaped slab waveguide 106.
End width Wp ₃Is quite wide.

Further, the first to third exponential function-shaped optical waveguides 2
Looking at the wavelength interval at a portion connected to the second sector slab waveguide 106 of 12 _{1-212 3.} While the wavelength interval between the first exponential function-shaped optical waveguide 212 ₁ and the second exponential function-shaped optical waveguide 212 ₂ is 100 GHz (gigahertz), the second exponential function-shaped optical waveguide 212 ₂ and the third exponential-shaped optical waveguide 212 ₂ The wavelength interval of the exponential function-shaped optical waveguide 212 ₃ is 200 GHz, which is twice that.

As described above, in the modified example of the first embodiment, not only the characteristics of the signal light are changed for each channel, but also the interval of the core portion for outputting the demultiplexed signal light is changed for each channel. . The effect of the former has already been explained. The latter effect has an effect of preventing new light wave crosstalk caused by mixing of the output signal lights by setting the unequal wavelength intervals. This is also described in Japanese Patent Application Laid-Open No. 08-212137, but it is limited to a taper shape, and in addition, it is not intended for the effect combined with changing the wavelength characteristic as in this modification. Absent.

<Second Embodiment>

FIG. 7 shows a main part of an arrayed waveguide grating module as a second embodiment of the present invention. In FIG. 7, the arrayed waveguide grating 100 of the first embodiment is used and is modularized. Therefore, in FIG. 7, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

The arrayed-waveguide grating module 301 of the second embodiment comprises a box-shaped case 302, a temperature control element 303 for heat generation or cooling, which is composed of a Peltier element arranged at the bottom of the box-shaped case 302, and the arrayed-waveguide grating 100. And a metal plate 305 interposed therebetween. In this second embodiment, a copper plate, an aluminum plate or their alloys having good thermal conductivity is used as the metal plate 305.

A groove is cut in the metal plate 305, and a temperature sensor 306 is embedded in the groove. The temperature detection output of the temperature sensor 306 is input to the temperature control circuit 308 to control the temperature of the temperature control element 303. The position 309 is a place where the temperature sensor 306 embedded in the metal plate 305 is pulled out. In this example, the temperature sensor 306 is a thermistor.

Optical fibers 311 and 312 are drawn out of the case 302 from the side of the first channel waveguide 102 and the side of the second channel waveguide 103 shown in FIG. 1 of the arrayed waveguide grating 100. . One of the optical fibers 311 is connected to the first channel waveguide 102 at one end, and the other end is connected to the light source side (not shown). Further, one end of the optical fiber 312 is connected to the second channel waveguide 103, and the other end thereof is connected to a circuit portion (not shown) for processing the demultiplexed signal light.

Although the array waveguide grating module 301 of the second embodiment does not have an attenuator built therein,
The arrayed-waveguide grating 100 already has a function as an attenuator for coarse adjustment as described in the embodiment. Therefore, it is not necessary to provide the coarse adjustment attenuator and the fine adjustment attenuator in a pair on the side of the second channel waveguide 103 of the arrayed waveguide grating module 301 as shown in FIG. Therefore, it is possible to incorporate only the fine adjustment attenuator into the arrayed-waveguide grating module 301 itself, if necessary.

<Third Embodiment>

FIG. 8 shows the outline of the configuration of the optical communication system in the third embodiment of the present invention. In this optical communication system, a SON (not shown) arranged on the transmission side
Signal light of N channels of wavelengths λ _{1 to} λ _N sent from an optical transmitter 401 connected to an ET (Synchronous Optical Network) device is an optical multiplexer (MUX) 402.
After being multiplexed by, the signal is amplified by the booster amplifier 403 and sent out to the optical transmission line 404. Signal light 40 multiplexed
5 is appropriately amplified by the in-line amplifier 406 and then passed through the pre-amplifier 407 to be the optical demultiplexer (DMUX) 4
The original wavelengths λ _{1 to} λ _N are separated by 08 and received by the optical receiver 409, but an appropriate number of nodes (OADMs) 411 _{1 to} 411 _M are arranged on the optical transmission line 404 on the way. . In these nodes 411 _{1 to} 411 _M , signal light of a desired wavelength is input / output. The optical multiplexer 402, the nodes 411 _{1 to} 411 _M , and the optical demultiplexer 408 are all composed of the arrayed waveguide grating 100 as shown in FIG. 1 in the first embodiment.

FIG. 9 shows an outline of the configuration of the node. Although the first node 411 ₁ (see FIG. 8) is shown here, the _{second to} Mth nodes 411 _{2 to} 411 _M also have the same configuration in principle. Optical transmission path shown in FIG. 8 404 is demultiplexed into N channels of signal light of the first entered in the input side arrayed waveguide grating 421 of the node 411 ₁ wavelength lambda ₁ to [lambda] _N, each wavelength lambda by ₁ to [lambda] of the two inputs and two outputs provided for each _N optical switch 422 ₁ ~422 _N, how the signal light of each wavelength lambda ₁ to [lambda] _N to the node-side receiving section 426 with (drop), node-side transmission Part 42
The signal light transmitted from 4 is added (Add). The output side of the two-input, two-output optical switches 422 _{1 to} 422 _N is provided with a corresponding fine attenuator (ATT) 4
After the gain is adjusted by 27 _{1 to} 427 _N , it is input to the output side arrayed waveguide grating 428. The output-side arrayed-waveguide grating 428 is an element having a configuration opposite to that of the input-side arrayed-waveguide grating 421. The output-side arrayed-waveguide grating 428 multiplexes N-channel signal light of wavelengths λ _{1 to} λ _N and outputs the signal light 405 to the optical transmission path 404. Will be sent out.

The fine adjustment attenuators 427 _{1 to} 427 _N are for finely adjusting the gain of the signal light output from the 2-input 2-output optical switches 422 _{1 to} 422 _N. The input-side arrayed-waveguide grating 421 is not provided because it functions as an attenuator for coarse adjustment of signal lights of wavelengths λ _{1 to} λ _N , as in the arrayed-waveguide grating 100 of the first embodiment. . Further, in the past, in order to adjust the overall gain, for example, a fixed gain equalizer may be arranged between the in-line amplifier 406 and the node 411 ₁ of this embodiment shown in FIG. In the case of the example, since the gain is adjusted in each channel, such a gain equalizer is unnecessary.

Thus, the first node 41 shown in FIG.
1 ₁ including the second to M-th node shown in FIG. 8 4
11 _{2 to} 411 _M and the optical demultiplexer 408 both use the arrayed waveguide grating 100 shown in FIG.
Then, when the monitor light is input from the input-side waveguide, the light of the wavelength λ _m output from the output-side waveguide (monitoring waveguide) is sequentially monitored, so that the wavelengths λ _{1 to} λ _n of The wavelength of the other waveguide on the output side from which light is output is corrected. For this purpose, as shown in FIG.
Output monitoring control devices 431 _{1 to} 431 _M and 431 _R are attached to the 11 _{1 to} 411 _M and the optical receiver 409, respectively, corresponding to these.

Even when the arrayed-waveguide grating 100 is used as a multiplexer, monitor light is input from the original output-side waveguide and output from the original input-side waveguide (monitoring waveguide). Similarly, wavelength correction can be performed by successively monitoring the above-described light having the wavelength λ _m . Therefore, although not shown in this embodiment, the array waveguide grating 1 on the output side array waveguide grating 428 side in the optical transmitter 401 and each of the nodes 411 _{1 to} 411 _M is not shown.
The correction of 00 is also possible, and an output monitoring control device for this purpose may be provided. Further, although the optical communication system using the monitor light is shown in the present embodiment, the input side arrayed waveguide grating 4 is similarly applied to the system which does not use the monitor light.
Similarly, the signal level can be adjusted for each channel by using No. 21 and the like.

FIG. 10 shows the level of the signal light of each part in this optical communication system.
The vertical axis represents the signal level at each wavelength. The figure (a) shows the wavelength λ output from the optical multiplexer 402.
And a representation of the signal light ₁ to [lambda] _N, illustrates a flat signal characteristics at the wavelength lambda ₁ to [lambda] _N. FIG. 11B shows the characteristic between the in-line amplifier 406 and the node 411 ₁ . Such non-uniformity of signal level is caused by the node 411 ₁
Is corrected by passing through the input side arrayed waveguide grating 421 and the fine adjustment attenuators 427 _{1 to} 427 _N.
FIG. 7C shows the signal light having the corrected wavelengths λ _{1 to} λ _N.

<Fourth Embodiment>

FIG. 11 shows the structure of the first boundary portion in the fourth embodiment of the present invention. The basic structure of the arrayed-waveguide grating according to the fourth embodiment is the same as that of the arrayed-waveguide grating 100 according to the first embodiment. Therefore, for a description of the entire arrayed waveguide grating, refer to FIG. 1 as appropriate. First boundary portion 1 in the fourth embodiment
08A is the second boundary portion 109 in the first embodiment.
Compared with, there is no difference except that the second channel waveguide 103 is changed to the first channel waveguide 102. That is, in the arrayed waveguide grating of the fourth embodiment, the first channel waveguide 102 and the second channel waveguide 103 are the same, and the input side and the output side of the signal light can be replaced. Has become.

The first advantage of such an arrayed waveguide grating
Is that the input side of the signal light can be used without particularly defining it. The second advantage is that, if the first boundary portion 108A is used on the input side, the first boundary portion 108 is dependent on the characteristics of the signal light input from the first channel waveguide 102.
That is, one desired exponential function-shaped optical waveguide 112 can be selected from the exponential function-shaped optical waveguides 112 _{1 to} 112 ₅ in A. Exponential function optical waveguide 1
Depending on whether you select one of 12 _{1-112 5,} the gain of the multiplexed signal light can be entirely adjusted.

It should be understood that the arrayed-waveguide grating module and the optical communication system can be constructed by using the arrayed-waveguide grating of the fourth embodiment.

In the embodiment described above, the case where the shape of the channel opening is an exponential function has been described, but the shape may be the same but different in size. Further, another shape that similarly changes the characteristics of the signal light may be present in the channel waveguide on the output side, or a plurality of shapes may be mixed. Some of these are illustrated below.

FIG. 12 shows the first core shape at the boundary between the second channel waveguide and the second fan-shaped slab waveguide.
It shows a modified example of. However for convenience of illustration in this figure, 3 of the second channel waveguide 103 first to third second channel waveguide 103 ₁ to 103 ₃ as shown in FIG. 1
It is assumed to be composed of one channel waveguide. A tapered optical waveguide 111 ₁ is arranged between the _first and second channel waveguides 103 ₁ and the second fan-shaped slab waveguide 106 instead of the exponential-shaped optical waveguide 112 ₁ shown by the broken line. There is. Between the second second channel waveguide 103 ₂ and the second fan-shaped slab waveguide 106,
The same exponential function-shaped optical waveguide 112 ₂ as shown in FIG. 3 or 5 is arranged. Between the third second channel waveguide 103 ₃ and the second fan-shaped slab waveguide 106,
Instead of the exponential function-shaped optical waveguide 112 ₃ shown by the broken line, a quadratic function-shaped (or parabolic shape) optical waveguide 5 is used.
13 ₃ are arranged.

By thus forming optical waveguides of various shapes for each channel, the signal for each channel output from the second channel waveguide 103 can be set or adjusted to have desired characteristics. . The shape of the core at the boundary between the second channel waveguide 103 and the second fan-shaped slab waveguide 106 in FIG. 1 may be different as described above, and various parameters that define these shapes and sizes may be set to desired values. By setting to, it is possible to give desired characteristics to each of the signal lights passing therethrough.

FIG. 13 shows the second channel waveguide 1 of FIG.
03 and the second fan-shaped slab waveguide 106, a tapered optical waveguide 111
And the exponential function-shaped optical waveguide 112 are connected in this order.

Contrary to FIG. 13, FIG. 14 is constructed by connecting an exponential function-shaped optical waveguide 112 and a tapered optical waveguide 111 in this order to the second channel waveguide 103. The input / output characteristics of the signal light are changed for each channel by using such a structure, a simple one type of shape, a combination of more shapes or a plurality of combinations of the same shape. Of course, you can.

[0118]

As described above, claims 1 to 1
According to the invention of any one of claims 4 and 24, before the demultiplexed signal light is propagated for each channel in the second channel waveguide, the second slab waveguide and the channel guide on the output side are guided. Since the shape or size of the opening of each channel that constitutes the connection point of the waveguide is made different for each channel as necessary, it is not necessary to adjust the characteristics such as the level of the signal light after demultiplexing. Or it can be reduced. As a result, the number of parts can be reduced and the insertion loss can be reduced. In addition, since the shape or size of these openings can be adjusted for each channel, not only the adjustment of the signal level for each channel, but also the flatness of the signal light, that is, whether it is a Gaussian shape or a flat top shape. It is also possible to set such as, setting the width of the signal light to be narrow band or wide band, and setting the interval of the signal light of each channel to, for example, 200 GHz or 100 GHz.

Further, according to the invention of claim 8, since the input direction of the signal light may be set to any side of the substrate,
The degree of freedom in designing the device or module is improved. In addition, by selecting a desired shape and size from the plurality of openings on the input side, it is possible to adjust the characteristics of the multiplexed light before demultiplexing.

In addition, claims 15 to 22, claim 25.
According to the arrayed-waveguide grating module of the invention described in any one of (1) to (5), before the demultiplexed signal light is propagated for each channel in the second channel waveguide, the second slab waveguide and the output side Since the shape or size of the opening of each channel that constitutes the connection point of the channel waveguide is made different for each channel as necessary, adjustment of characteristics such as the level of the signal light after demultiplexing is performed by this. It can be eliminated or reduced. As a result, the number of components of the arrayed waveguide grating module can be reduced and the insertion loss can be reduced.
Further, since the arrayed waveguide grating used in the present invention can adjust the shape or size of the openings for each channel, not only the adjustment of the signal level for each channel but also the flatness of the signal light, that is, Gaussian The shape of the signal light is set to be flat or top, the width of the signal light is adjusted to be narrow band or wide band, and the interval of the signal light of each channel is set to, for example, 20.
The setting of 0 GHz or 100 GHz can be made possible, and the flexibility of the arrayed waveguide grating module can be increased.

Further, according to the optical communication system of the twenty-third or twenty-sixth aspect, since the optical communication system is configured using the arrayed-waveguide grating as the invention of the first aspect, the arrayed-waveguide grating is used. It is possible to eliminate or reduce the adjustment of the characteristics such as the level of the signal light after being demultiplexed for each. As a result, the number of parts constituting the system can be significantly reduced, and the insertion loss can be reduced. Further, since the arrayed waveguide grating used in the present invention can adjust the shape or size of the openings for each channel, not only the adjustment of the signal level for each channel but also the flatness of the signal light, that is, Gaussian Setting of the shape or the flat top shape, setting of adjusting the width of the signal light to narrow band or wide band, and the interval of the signal light of each channel, for example, 200 GHz or 100 GHz
It is also possible to set whether or not to increase the flexibility of the system.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an arrayed waveguide grating according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view showing a shape of a core at a boundary portion between the first channel waveguide and the first fan-shaped slab waveguide shown in FIG.

3 is a partially enlarged view showing a shape of a core at a boundary portion between the second channel waveguide and the second fan-shaped slab waveguide of FIG.

FIG. 4 is an explanatory view showing one shape of the exponential function-shaped optical waveguide shown in FIG.

5 is a plan view specifically showing a boundary portion between the second channel waveguide and the second fan-shaped slab waveguide shown in FIG.

FIG. 6 is a plan view specifically showing a boundary portion between a second channel waveguide and a second fan-shaped slab waveguide in a modification of the first embodiment of the present invention.

FIG. 7 is a sectional view showing an essential part of an arrayed waveguide grating module as a second embodiment of the present invention.

FIG. 8 is a system configuration diagram showing an outline of a configuration of an optical communication system in a third exemplary embodiment of the present invention.

FIG. 9 is a block diagram showing an outline of a node configuration according to a third exemplary embodiment of the present invention.

FIG. 10 is a characteristic diagram showing the level of signal light of each part in the third embodiment.

FIG. 11 is a plan view showing a configuration of a first boundary portion in the fourth exemplary embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a first modified example of the shape of the core at the boundary between the second channel waveguide and the second fan-shaped slab waveguide.

FIG. 13 is an explanatory diagram showing a second modified example of the shape of the core at the boundary between the second channel waveguide and the second fan-shaped slab waveguide.

FIG. 14 is an explanatory diagram of a core portion in which an exponential function-shaped optical waveguide and a tapered optical waveguide are connected to a second channel waveguide in this order.

FIG. 15 is a perspective view showing an example of an arrayed-waveguide grating proposed for realizing a transmission characteristic having a flat peak level.

16 is an explanatory diagram in which the boundary portions on the incident side and the emission side of the first fan-shaped slab waveguide of the arrayed waveguide grating shown in FIG. 15 are appropriately enlarged and illustrated.

FIG. 17 is an explanatory diagram in which the boundary portions on the incident side and the emission side of the second fan-shaped slab waveguide of the arrayed waveguide grating shown in FIG. 15 are appropriately enlarged and shown.

FIG. 18 is an explanatory diagram showing the configuration of an arrayed waveguide grating according to another conventional proposal.

FIG. 19 is a block diagram showing a configuration of a receiving-side device of a conventional optical communication system.

[Explanation of symbols]

100 array waveguide grating 102 first channel waveguide 103 second channel waveguide 104 channel waveguide array 105 first fan-shaped slab waveguide 106 second fan-shaped slab waveguide 108, 108A first boundary portion 109 Boundary portion 111 of 2 Tapered optical waveguides 112, 212 Exponential optical waveguide 301 Array waveguide grating module 311, 312 Optical fiber 408 Optical demultiplexer 411 Node 421 Input side array waveguide grating 427 Fine adjustment attenuators λ ₁ , λ ₂ , ... λ _n wavelength

Claims (26)

[Claims] 1. A predetermined substrate, first and second channel waveguides arranged on the substrate for propagating light waves, and lengths of adjacent waveguides are sequentially lengthened by a predetermined difference. And a first slab waveguide connecting one end of the first channel waveguide and one end of the channel waveguide array, the second channel conductor formed on the substrate, A second slab waveguide that connects one end of a waveguide and the other end of the channel waveguide array and splits the wavelength-multiplexed light that has passed through the channel waveguide array. An arrayed waveguide grating, characterized in that the shape and size of the openings of each channel constituting the second channel waveguide with respect to the waveguide are different from at least some of the openings. 2. The shape of the opening of each channel constituting the second channel waveguide is tapered, and the optical waveguide width Wt at the taper end or the length of the taper is at least part of the remaining channel. The arrayed waveguide grating according to claim 1, wherein the arrayed waveguide grating is different from the opening. 3. The shape and size of the opening of each channel forming the second channel waveguide is such that the traveling direction of the light wave is X, the termination width at the connection point with the slab waveguide is Wp, and the light wave is Where Wc is the spread of the waveguide portion in the direction orthogonal to the traveling direction X of, and a is a parameter giving the shape of the exponential function, W (X) = (Wp-Wc) * (1-exp (-a *
X)) + Wc, wherein at least some of these parameters are different for at least some channels and the rest of the channels. 4. The shape and size of the opening of each channel forming the second channel waveguide is a parabolic shape and its size.
An arrayed waveguide grating as described. 5. The shape and size of the opening of each channel forming the second channel waveguide is tapered and its size, and the traveling direction of the light wave is X, and the shape of the opening and the size of the opening are When Wp is the terminal width, Wc is the spread of the waveguide portion in the direction orthogonal to the traveling direction X of the light wave, and a is a parameter giving the shape of the exponential function, W (X) = (Wp-Wc) * (1 -Exp (-a *
The arrayed waveguide grating according to claim 1, wherein a plurality of shapes and sizes thereof represented by the formula X)) + Wc, and parabolic shapes and sizes thereof are combined. 6. The array according to claim 5, wherein the combined shape and size is a combination of different shapes and sizes in the traveling direction of the signal light of the corresponding channel. Waveguide grating. 7. The arrayed waveguide grating according to claim 5, wherein the plurality of combined shapes and sizes have different types of shapes and sizes selected for different channels. 8. The shape and size of the openings of each channel constituting the first channel waveguide with respect to the first slab waveguide are such that at least some of them are different from the remaining openings. The arrayed waveguide grating according to claim 1. 9. The shape of the opening of each channel constituting the first channel waveguide is tapered, and the optical waveguide width Wt at the taper end or the length of the taper is at least part of the remaining channel. 9. The arrayed waveguide grating according to claim 8, wherein the arrayed waveguide grating is different from the opening. 10. The shape and size of the opening of each channel constituting the first channel waveguide is such that the traveling direction of the light wave is X, the termination width at the connection point with the slab waveguide is Wp, and the light wave is Where Wc is the spread of the waveguide portion in the direction orthogonal to the traveling direction X of, and a is a parameter giving the shape of the exponential function, W (X) = (Wp-Wc) * (1-exp (-a *
X)) + Wc, wherein at least some of these parameters are different for at least some of the channels and the rest of the channels. 11. The arrayed waveguide grating according to claim 8, wherein the shape and size of the opening of each channel forming the first channel waveguide is a parabolic shape and its size. 12. The shape and size of the opening of each channel forming the first channel waveguide is tapered and its size, and the traveling direction of the light wave is X, and the shape of the opening and the size of the opening are as follows. When Wp is the terminal width, Wc is the spread of the waveguide portion in the direction orthogonal to the traveling direction X of the light wave, and a is a parameter giving the shape of the exponential function, W (X) = (Wp-Wc) * (1 -Exp (-a *
9. The arrayed waveguide grating according to claim 8, wherein a plurality of the shapes and sizes thereof represented by the formula X)) + Wc and the parabolic shapes and sizes thereof are combined. 13. The array according to claim 12, wherein the combined shape and size is a combination of different shapes and sizes in the traveling direction of the signal light of the corresponding channel. Waveguide grating. 14. The arrayed waveguide grating according to claim 12, wherein the plurality of combined shapes and sizes have different types of shapes and sizes selected for different channels. 15. A predetermined substrate, first and second channel waveguides arranged on the substrate for propagating a light wave, and adjacent waveguides are sequentially lengthened with a predetermined difference. And a first slab waveguide for connecting one end of the first channel waveguide and one end of the channel waveguide array via a waveguide portion of a first shape, The one end of the second channel waveguide and the other end of the channel waveguide array formed on the substrate
Array waveguide element including a second slab waveguide connected through a waveguide portion having the shape of, a fiber array optically coupled to the waveguide element, the array waveguide element and the fiber array And a shape of the opening of each channel constituting the second channel waveguide with respect to the second slab waveguide, at least a part of which is different from the remaining openings. An arrayed-waveguide grating module, which is characterized in that 16. The shape and size of the openings of each channel forming the first channel waveguide with respect to the first slab waveguide are such that at least some of them are different from the remaining openings. The arrayed waveguide grating module according to claim 15. 17. The shape of the opening of each channel is tapered, and the optical waveguide width Wt at the taper end or the length of the taper is different from the remaining openings in at least a part of the channel. The arrayed waveguide grating module according to claim 15 or 16. 18. The shape and size of the opening of each channel are such that the light wave traveling direction is X, the terminal width at the connection point with the slab waveguide is Wp, and the light guide direction is orthogonal to the light wave traveling direction X. When the spread of the waveguide part is Wc and the parameter giving the shape of the exponential function is a, W (X) = (Wp-Wc) * (1-exp (-a *
X)) + Wc, wherein at least some of these parameters are different for at least some of the channels and the rest of the channels.
An arrayed waveguide grating module as described. 19. The arrayed waveguide grating module according to claim 15 or 16, wherein the shape and size of the opening of each channel is a parabolic shape and its size. 20. The shape and size of the opening of each channel are tapered and their size, X is the traveling direction of the light wave, Wp is the terminal width at the connection point with the slab waveguide, and X is the traveling direction of the light wave. When Wc is the spread of the waveguide portion in the direction orthogonal to and the parameter giving the shape of the exponential function is a, W (X) = (Wp-Wc) * (1-exp (-a *
The arrayed waveguide grating module according to claim 15 or 16, characterized in that a plurality of shapes and sizes thereof represented by the formula X)) + Wc and parabolic shapes and sizes thereof are combined. . 21. The array according to claim 20, wherein the plurality of combined shapes and sizes are combinations of different shapes and sizes in a traveling direction of signal light of a corresponding channel. Waveguide grating module. 22. The arrayed waveguide grating module according to claim 20, wherein the shape and size of the plurality of combinations are selected from different types of shapes and sizes for different channels. . 23. An arrayed waveguide grating in which respective transmission lines for transmitting wavelength-division-multiplexed signal light are connected by nodes, and each node separates the wavelength-division-multiplexed signal light into signal lights of respective wavelengths. , An arrayed waveguide grating for wavelength-division-multiplexing the signal light separated into each wavelength is provided, and at least one of these arrayed waveguide gratings is disposed on a predetermined substrate and on this substrate. First and second channel waveguides for propagating a light wave, a channel waveguide array configured such that adjacent waveguides sequentially increase in length by a predetermined difference, and the first channel waveguide A first slab waveguide connecting one end of the channel waveguide array to one end of the channel waveguide array, and one end of the second channel waveguide formed on the substrate to the other end of the channel waveguide array, Said A second slab waveguide for demultiplexing wavelength-division-multiplexed light that has passed through the channel waveguide array, and an opening of each channel constituting the second channel waveguide with respect to the second slab waveguide. An optical communication system, characterized in that at least some of them are different in shape and size from the remaining openings. 24. The array according to claim 1, wherein the arrangement intervals of the openings of the respective channels forming the second channel waveguide with respect to the second slab waveguide are unequal wavelength intervals. Waveguide grating. 25. The array according to claim 15, wherein the arrangement intervals of the openings of the respective channels forming the second channel waveguide with respect to the second slab waveguide are unequal wavelength intervals. Waveguide grating module. 26. The optical system according to claim 23, wherein the arrangement intervals of the openings of the respective channels forming the second channel waveguide with respect to the second slab waveguide are unequal wavelength intervals. Communications system.