JPH112734A - Optical waveguide circuit with optical characteristic adjusting plate and its manufacture and manufacturing device for optical characteristic adjusting plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide circuit with a phase adjusting plate adjusting an optical path length error occurring at the time of manufacturing a planar optical circuit with additional processing performed after manufacturing by providing a groove traversing all of plural optical waveguides and installing the plate adjusting the optical characteristic of the optical waveguide on its groove. SOLUTION: This optical waveguide circuit is constituted of a groove 16 traversing plural waveguides 14-1, 14-2, a plate (optical characteristic adjusting plate) 17 spatially changing the optical characteristic in advance so as to correct the optical characteristic of a part intersecting with the optical waveguide 14 when the groove 16 is inserted and an adhesive fixing the optical characteristic adjusting plate 17 to the groove 16. In this optical waveguide circuit, the optical characteristics of the light propagating through the waveguide 14-1, 14-2 are changed in accordance with the optical characteristic of the optical characteristic adjusting plate 17 of the intersecting parts with the waveguides 14-1, 14-2. Thus, the optical characteristics of the waveguides 14-1, 14-2 are measured and thereafter, the optical characteristic adjusting plate 17 is fixed to the groove 16 by using the adhesive to adjust the optical characteristics of the waveguides 14-1, 14-2 to required values.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide circuit used in fields such as optical communication and optical information processing, and more specifically, to a plurality of optical waveguides formed on a substrate of an optical waveguide circuit. An optical waveguide circuit with an optical characteristic adjusting plate having a configuration in which an unavoidable error between an optical characteristic value on the input side and an optical characteristic value on the output side is corrected by an optical characteristic adjusting plate, a method for manufacturing the optical waveguide circuit, and an apparatus for manufacturing the optical characteristic adjusting plate It is about.

As the optical waveguide circuit, for example, there is a two-beam or multi-beam optical interferometer constituted by an optical waveguide formed on a plane. The optical characteristics include, for example, the phase and amplitude of light propagating through the plurality of optical waveguides and the birefringence of the optical waveguide.

[0003]

2. Description of the Related Art In recent years, studies on a planar lightwave circuit (PLC = Planar Lightwave Circuit) composed of a silica-based optical waveguide formed on a silicon substrate have been actively conducted. Here, switching and wavelength multiplexing / demultiplexing functions are realized by using interference of two light beams or multiple light beams as in a Mach-Zehnder interferometer or an arrayed waveguide grating wavelength multiplexing / demultiplexing device.

For details on thermo-optic switches using a Mach-Zehnder interferometer, see Okuno et al., “Quartz-based thermo-optic switch technology,” NTT R & D vol.143, No. 11, pp. 1289-12.
98, Nov. 1994. This switch realizes a switch function by thermally controlling the optical path length difference between the two-arm waveguide with a thin film heater provided on the waveguide surface.

FIG. 1 shows an outline of this circuit configuration, and FIG.
2 is an enlarged sectional view taken along line II-II of FIG.

In FIG. 1, reference numerals 101-a and 102-a denote input ports, 103 denotes a silicon substrate, 104-1 denotes a first arm waveguide, and 104-2 denotes a second arm waveguide.
Reference numeral 5 denotes a thin film heater, and in FIG. 2, reference numeral 109 denotes a cladding layer, and reference numeral 114 denotes a core layer.

FIG. 3 shows an example of the characteristics of the manufactured 2 × 2 thermo-optical switch. The horizontal axis in FIG. 3 is the power applied to the thin film heater, and the vertical axis is the through port (101-a → 101).
-B) shows the transmittance of light to b). The transmittance changes depending on the electric power applied to the thin film heater. Here, the power is Pl and P
By switching in time with 2, this circuit becomes 2 ×
Operates as a two light switch.

Here, the two arm waveguides 104-1 and 104-2 shown in FIG. 1 are designed to have the same length. Therefore, the transmittance to the through port should be minimized when no power is applied. That is,
P1 should be 0.

However, the length of the two arm waveguides 104-1 and 104-2 is set to 0.1 μm due to a manufacturing error of the waveguide.
An optical path length difference of the order occurs, which causes P1
≠ 0. Here, since the optical path length error of 0.1 μm is about 10% of the optical wavelength, the value of P1 is a value that cannot be ignored compared to the switch power (P2−P1). On the other hand, an optical path length error on the order of 0.1 μm is an error of about 10 ⁻⁵ for the arm waveguides 104-1 and 104-2 of about 10 mm, and it is difficult to significantly reduce this value due to manufacturing technology. .

The power of P1 increases the power consumption of the switch, and its value is preferably set to zero.

In the arrayed waveguide grating type wavelength multiplexer / demultiplexer, the optical path lengths arranged in parallel differ from each other by n × △ L.
A wavelength multiplexing / demultiplexing function of light is realized by interference of a plurality of lights propagated through about 100 arm waveguides.

Here, n is the effective refractive index of the waveguide, and ΔL is a value of about 10 to 100 μm. See H.Takaha
si et al., ”Arrayed Waveguide Grating for Waveleng
th Division Multi / Demultiplexer with Nanometre Res
olution, "Electron. Lett., vol. 26, no. 2, pp. 87-88, 1990.
It is described in.

FIG. 4 shows an outline of the circuit configuration. FIG.
Reference numeral 110 denotes an input waveguide, 111 denotes an output waveguide,
12 is a slab waveguide, 113 is an array waveguide and 10
Reference numeral 3 denotes a silicon substrate.

FIG. 5 shows a transmission wavelength characteristic from the center port to the center output port of the arrayed waveguide grating type wavelength multiplexer / demultiplexer shown in FIG. As is clear from FIG. 5, only a specific wavelength is transmitted from the central input port to the central output port, and light of other wavelengths is blocked.

At present, the crosstalk expressed by the ratio of the transmittance at the stop wavelength to the transmittance at the transmission wavelength is -30 dB.
It is about.

[0016] Reducing the crosstalk is an extremely important issue as a wavelength multiplexing / demultiplexing function. The first cause of this crosstalk being limited to about −30 dB is that the optical path length difference of n × ΔL set in the array waveguide fluctuates on the order of 0.1 μm due to manufacturing errors. This is because an error occurs in the phase of the light passing through.

The second cause is that the amplitude of the transmitted light from each path distributed from the branch portion to each array waveguide and coupled again by the multiplexing portion is designed by the non-uniformity of the waveguide loss and the like. Deviation from the value. That is, an amplitude error occurs.

Furthermore, for example, in an optical circuit having a large area occupied by a waveguide, such as an arrayed waveguide grating having a small interval between adjacent frequencies, variation in birefringence occurs in the optical waveguide constituting the optical circuit. For this reason, the distribution of the phase differs depending on the polarization of the optical waveguide, and polarization dependence occurs in the characteristics.

[0019]

As described above, the PLC
The optical path length error on the order of 0.1 μm during fabrication is 2
This causes deterioration of the characteristics of the light beam or multi-beam interferometer. Therefore, if the optical path length error can be adjusted by any method, the characteristics of the interferometer can be improved.

Further, the deviation of the amplitude of the transmitted light from each path, which is distributed to a plurality of channel waveguides from the branch portion and is coupled again by the multiplexing portion, from the design value, which occurs at the time of manufacturing the PLC, is two light beams or This causes deterioration of characteristics of the multi-beam interferometer. Therefore, if the deviation from the designed value of the amplitude can be adjusted by any method, the characteristics of the interferometer can be improved. Further, by adjusting the amplitude and phase characteristics to desired values, it becomes possible to add functions such as flattening of a pass wavelength band and dispersion control.

Furthermore, in an optical circuit having a large area occupied by a waveguide, the characteristics of the optical waveguide constituting the optical circuit are polarization dependent due to variations in birefringence. Therefore, if the variation in the birefringence can be adjusted by any method, a high-performance optical circuit can be manufactured irrespective of polarization.

In view of the circumstances described above, one of the objects of the present invention is to provide an optical waveguide circuit with a phase adjusting plate in which an optical path length error generated at the time of manufacturing a PLC is adjusted by additional processing performed after the manufacturing. Another object of the present invention is to provide an optical waveguide circuit with an amplitude adjusting plate that adjusts the amplitude characteristics of light by additional processing performed after manufacturing a PLC, and a method of manufacturing the optical waveguide circuit. An object of the present invention is to provide an optical waveguide circuit with a birefringence adjusting plate for adjusting the birefringence of light by additional processing performed after manufacturing a PLC, and a method for manufacturing the same. The present invention also includes a configuration in which both the phase adjustment plate and the amplitude adjustment plate are provided in the same optical waveguide circuit to further improve the optical characteristics. The present invention also includes an apparatus for manufacturing these optical property adjusting plates.

[0023]

According to another aspect of the present invention, there is provided an optical waveguide circuit having an optical characteristic adjusting plate according to the present invention, comprising a plurality of optical waveguides on a substrate. And a groove which traverses all of the plurality of optical waveguides, and a plate for adjusting the optical characteristics of the optical waveguide circuit is provided in the groove.

According to a second aspect of the present invention, in the optical waveguide circuit of the first aspect, the optical characteristic of the optical waveguide is a phase of light propagating through the optical waveguide, and the optical characteristic adjusting plate is provided. Is a phase adjusting plate.

According to a third aspect of the present invention, in the optical waveguide circuit according to the second aspect, the phase adjusting plate is a film having a uniform refractive index, which is processed to be uneven in the longitudinal direction. And

According to a fourth aspect of the present invention, in the optical waveguide circuit of the second aspect, the refractive index of the phase adjusting plate is different from that of the plurality of waveguides. .

According to a fifth aspect of the present invention, in the optical waveguide circuit of the third aspect, a concave portion of a film constituting the phase adjusting plate is filled with a transparent material.

According to a sixth aspect of the present invention, in the optical waveguide circuit of the fifth aspect, a refractive index of the film is different from a refractive index of a transparent material filling a concave portion of the film. .

According to a seventh aspect of the present invention, in the optical waveguide circuit of the first aspect, the optical characteristic of the optical waveguide is an amplitude of light propagating through the optical waveguide, and Is an amplitude adjusting plate.

An optical waveguide circuit according to an eighth aspect of the present invention is the optical waveguide circuit according to the seventh aspect, wherein the amplitude adjusting plate is a film having a uniform absorption coefficient which is processed to be uneven in the longitudinal direction. And

According to a ninth aspect of the present invention, in the optical waveguide circuit of the eighth aspect, a concave portion of a film constituting the amplitude adjusting plate is filled with a transparent material.

According to a tenth aspect of the present invention, in the optical waveguide circuit of the ninth aspect, the refractive index of the film is the same as the refractive index of a transparent material filling the concave portion of the film. And

According to an eleventh aspect of the present invention, in the optical waveguide circuit according to the seventh aspect, the amplitude adjustment plate is formed of a film having a constant thickness and formed on the film in a longitudinal direction of the film. And metal films having different thicknesses.

According to a twelfth aspect of the present invention, in the optical waveguide circuit of the first aspect, the optical characteristic of the optical waveguide is a phase and an amplitude of light propagating through the optical waveguide. The adjustment plate is a phase and amplitude adjustment plate.

According to a thirteenth aspect of the present invention, in the optical waveguide circuit of the first aspect, the optical characteristic of the optical waveguide is a birefringence of light propagating through the optical waveguide, and the optical characteristic adjustment is performed. The plate is a birefringence adjusting plate.

According to a fourteenth aspect of the present invention, in the optical waveguide circuit of the first aspect, the gap between the inner wall of the groove and the optical property adjusting plate is filled with an optically transparent adhesive. It is characterized.

According to a fifteenth aspect of the present invention, in the optical waveguide circuit according to the fourteenth aspect, the optical property adjusting plate is a phase adjusting plate, and the refractive index of the phase adjusting plate and the refractive index of the adhesive. The rate is different.

According to a sixteenth aspect of the present invention, in the optical waveguide circuit of the fourteenth aspect, the optical characteristic adjusting plate is an amplitude adjusting plate, and the refractive index of the amplitude adjusting plate and the refractive index of the adhesive. The rate is the same.

In an optical waveguide circuit according to a seventeenth aspect of the present invention, in the optical waveguide circuit according to the fourteenth aspect, the optical characteristic adjusting plate is a birefringence adjusting plate, and one of the birefringence adjusting plates has a different refractive index from the other. It is characterized in that the refractive index of the adhesive is the same.

According to an eighteenth aspect of the present invention, in the optical waveguide circuit according to the first aspect, at least two of the grooves are formed, and the optical characteristic adjusting plate installed in one of the grooves is provided. It is a phase adjustment plate, and the optical characteristic adjustment plate provided in the other one is an amplitude adjustment plate.

A nineteenth aspect of the present invention relates to a method for manufacturing an optical waveguide circuit with an optical property adjusting plate, wherein an optical waveguide circuit having a plurality of optical waveguides on a substrate includes all of the plurality of optical waveguides. A groove forming step of forming a groove that crosses the optical waveguide, and measuring the optical characteristic values of the input side and the output side of each optical waveguide when light propagates through the plurality of optical waveguides, and the optical characteristic value of each input side. An optical characteristic adjustment amount determining step of determining an adjustment amount of an optical characteristic required for each optical waveguide from an error of an optical characteristic value on the output side, and the optical characteristic value is locally changed corresponding to each of the optical characteristic adjustment amounts. An optical property adjusting plate manufacturing step of manufacturing an optical property adjusting plate, and an optical property adjusting plate setting step of setting the optical property adjusting plate in the groove are provided.

In the manufacturing method according to a twentieth aspect of the present invention, in the manufacturing method according to the nineteenth aspect, the optical characteristic of the optical waveguide is a phase of light propagating through the optical waveguide, and the optical characteristic adjusting plate is a phase adjusting plate. A step of forming irregularities in the longitudinal direction on the film having a uniform refractive index in accordance with the amount of phase adjustment of each optical waveguide.

According to a twenty-first aspect of the present invention, in the manufacturing method of the twentieth aspect, the step of manufacturing the optical property adjusting plate for manufacturing the phase adjusting plate further comprises the step of forming a uniform refractive index having irregularities. And a film flattening step of flattening the film by filling a concave portion of the film having a refractive index different from that of the film with a transparent material.

In the manufacturing method according to a twenty-second aspect of the present invention, in the manufacturing method according to the nineteenth aspect, the optical characteristic of the optical waveguide is an amplitude of light propagating through the optical waveguide, and the optical characteristic adjusting plate adjusts the amplitude. Wherein the step of preparing the optical property adjusting plate comprises a step of forming irregularities in the longitudinal direction on the film having a uniform absorption coefficient in accordance with the amplitude adjustment amount of each optical waveguide.

In the manufacturing method according to a twenty-third aspect of the present invention, in the manufacturing method according to the twenty-second aspect, the step of manufacturing the optical property adjusting plate for manufacturing the amplitude adjusting plate further includes a step of forming a uniform absorption coefficient having irregularities. And a film flattening step of flattening the film by filling a concave portion of the film having the same refractive index as that of the film with a transparent material.

According to a twenty-fourth aspect of the present invention, in the manufacturing method of the nineteenth aspect, the optical characteristic of the optical waveguide is an amplitude of light propagating through the optical waveguide, and the optical characteristic adjusting plate is an amplitude adjusting plate. A metal film having a thickness change in the longitudinal direction according to the amplitude adjustment amount of each of the optical waveguides, on a film having a uniform absorption coefficient and a constant thickness, wherein Characterized by a step of performing

According to a twenty-fifth aspect of the present invention, in the manufacturing method of the nineteenth aspect, the optical characteristics of the optical waveguide are a phase and an amplitude of light propagating through the optical waveguide.
The optical property adjusting plate is a phase amplitude adjusting plate, and the optical property adjusting plate manufacturing step forms, in a film having a uniform refractive index, unevenness in the longitudinal direction according to the phase adjustment amount of each optical waveguide. And a step of forming a metal film having a thickness change in the longitudinal direction corresponding to the amplitude adjustment amount of each optical waveguide on the film.

According to a twenty-sixth aspect of the present invention, in the manufacturing method of the nineteenth aspect, after the step of installing the optical characteristic adjusting plate, the gap between the inner wall of the groove and the optical characteristic adjusting plate is optically formed. It has an adhesive filling step of filling a transparent adhesive.

According to a twenty-seventh aspect of the present invention, in the manufacturing method of the twenty-sixth aspect, the optical property adjusting plate is a phase adjusting plate, and the refractive index of the phase adjusting plate and the refractive index of the adhesive are different from each other. Are characterized by differentiating from each other.

According to a twenty-eighth aspect of the present invention, in the manufacturing method of the twenty-sixth aspect, the optical characteristic adjusting plate is an amplitude adjusting plate, and the refractive index of the amplitude adjusting plate and the refractive index of the adhesive are different from each other. Are the same.

A manufacturing method according to a twenty-ninth aspect of the present invention is the manufacturing method according to the nineteenth aspect, wherein at least two grooves are formed in the groove forming step, and one of the grooves is formed as an optical characteristic adjusting plate. A plate is provided, and the other is provided with an amplitude adjusting plate as an optical characteristic adjusting plate.

Further, according to the present invention, in the optical waveguide circuit having a plurality of optical waveguides on a substrate and a groove crossing all of the plurality of optical waveguides, the plurality of optical waveguides are provided in the groove. An apparatus for manufacturing an optical characteristic adjustment plate installed to adjust an error between each input side value and output side value of optical characteristics of an optical waveguide, the input side of a plurality of optical waveguides of the optical waveguide circuit. Means for measuring an error in optical characteristics between the output side and
An adjustment value calculation unit that calculates an optical characteristic adjustment value based on the error value obtained by the error measurement unit; and an optical characteristic in a longitudinal direction of a plate having optical characteristics based on each adjustment value of the plurality of optical waveguides. An optical property adjusting plate producing means for obtaining the optical property adjusting plate by changing the distribution.

[0053]

Embodiments of the present invention will be described below.

In the optical waveguide circuit of the present invention, the optical characteristics of the groove crossing the plurality of waveguides constituting the optical waveguide and the optical characteristics of the portion intersecting the optical waveguide when the groove is inserted are corrected in advance. It is composed of a spatially changed plate and an adhesive for fixing the plate in the groove.

Hereinafter, in the present invention, a plate that has been processed in advance so that the optical characteristics at the intersection with the waveguide when the groove is inserted can be adjusted is referred to as an optical characteristic adjusting plate.

According to this configuration, the optical characteristics of the light propagating through the plurality of waveguides change according to the optical characteristics of the optical characteristic adjusting plate at the intersection with the waveguide.

Therefore, the optical characteristics of the plurality of waveguides are measured, and then the optical characteristic adjusting plate processed so as to adjust the optical characteristics is fixed to the groove using an adhesive, whereby the plurality of waveguides is obtained. Can be adjusted to a desired value.

As a portion of the optical circuit to be adjusted, in addition to a linear waveguide or a curved waveguide, an interference optical path of an interference type optical circuit, or a multiplexing / demultiplexing section such as a 3 dB coupler or a slab waveguide may be used. The present invention is effective.

When the optical characteristic to be adjusted is the phase of light, and the optical characteristic adjusting plate is a phase adjusting plate, the light propagating through the plurality of waveguides is reduced by the optical thickness of the phase adjusting plate at the intersection with the waveguide. Accordingly, different phase changes are provided. As a result, for example, it is possible to adjust the optical path length error of the optical waveguide constituting the interferometer type optical circuit, and to remarkably improve the characteristics of the optical circuit.

When the optical characteristic to be adjusted is the amplitude of light and the optical characteristic adjusting plate is an amplitude adjusting plate, the light propagating through the plurality of waveguides depends on the loss of the amplitude adjusting plate at the intersection with the waveguide. , Different losses are given. As a result, for example, the amplitude distribution of the optical waveguide forming the interferometer type optical circuit can be adjusted, and the characteristics of the optical circuit can be significantly improved.

When the optical characteristic to be adjusted is the birefringence of light and the optical characteristic adjusting plate is a birefringence adjusting plate, the light propagating through the plurality of waveguides passes through the optical axis of the birefringence adjusting plate at the intersection with the waveguide. Depending on the thickness, different birefringence can be provided. As a result, for example, the birefringence error of the optical waveguide forming the interferometer type optical circuit can be adjusted, and the characteristics of the optical circuit can be significantly improved.

[0062]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below, but the present invention is not limited thereto.

Embodiment 1 FIG. 6 shows a Mach-Zehnder interferometer type 2 × 2 optical switch as a first embodiment of the present invention. 6, reference numerals 11-a and 12-a denote input ports, reference numerals 11-b and 12-b denote output ports, 13 denotes a silicon substrate, 14-1 denotes a first arm waveguide, and 14-2 denotes a second arm waveguide. , 15 is a thin film heater, 16 is a groove, and 17 is a phase adjusting plate.

FIG. 7 is an enlarged sectional view taken along the line VII-VII in FIG.

In this embodiment, after a groove 16 having a constant width intersecting an arm waveguide of a conventional Mach-Zehnder interferometer type 2 × 2 optical switch is processed, a phase having a constant in-plane refractive index whose thickness is spatially changed is formed. An adjusting plate 17 (FIG. 8) is inserted into the groove 16.

Further, in order to fix the phase adjusting plate 17 in the groove 16, an adhesive 18 is filled as shown in FIG.

Here, the film 17 constituting the phase adjusting plate 17
When the in-plane refractive index of a is n ₁ and the refractive index of the adhesive 18 is n ₂ , the optical path length of the groove 16 felt by the two arm waveguides 14-1 and 14-2 is given by the following equations, respectively. Can be

The optical path length of the groove in the first arm waveguide 14-1 = n ₁ × w ₁ + n ₂ × (w ₀ −w ₁ ) The optical path length of the groove in the second arm waveguide 14-2 = n ₁
× w ₂ + n ₂ × (w ₀ −w ₂ ) Therefore, the relative optical path length difference is (n ₁ −n ₂ ) × (w
₂ −w ₁ ).

Here, the in-plane refractive index of the film is n ₁ ,
The refractive index of the adhesive is n ₂ , the film thickness intersecting the first arm waveguide 14-1 is w ₁ , the film thickness intersecting the second arm waveguide 14-2 is w ₂ , and the width of the groove 16 is Let _w0 .

In this embodiment, the refractive index difference (n ₁ -n ₂ ) between the in-plane refractive index of the film and the refractive index of the adhesive and the difference in film thickness (w
By appropriately giving _2- w ₁ ), the optical path length difference of the arm waveguide caused by the manufacturing error is adjusted.

The Mach-Zehnder interferometer type 2 × 2 of this embodiment
The procedure for manufacturing the optical switch is described below.

A Mach-Zehnder interferometer is manufactured on a silicon substrate by a fire deposition method and a reactive ion etching method by a technique similar to the conventional technique.

A groove 16 having a width of 20 μm and a depth of 150 μm is processed by a dicing saw. The groove 16 is filled with an adhesive 18 having a refractive index n2.

[0074] measure the change in light transmittance with respect to the thin film heater power applied as shown in FIG. 10 in this state, P _1,
Determine the P _2.

(N ₁ −n ₂ ) × (w ₂ −w ₁ ) =
A film thickness difference (w ₂ −w ₁ ) satisfying (λ / 2) × P ₁ / (P ₂ −P ₁ ) is obtained. Here, λ is a light wavelength, and in this embodiment, light of λ = 1.55 μm was used.

A polyimide film 17a having an in-plane refractive index n1
Is processed by a method using a processing jig 30 as shown in FIG. 9 so that the film thickness becomes w ₁ and w ₂ . A film obtained by processing this film to a predetermined thickness is called a phase adjusting plate 17 (FIG. 8).

The processed phase adjusting plate 17 is inserted into the groove 16 formed above and fixed with the adhesive 18.

When a 2 × 2 optical switch was actually manufactured by using a quartz-based PLC technology, P _{1 was} 20 mW and P ₂ was 420 mW.

The refractive index of the used adhesive 18 and the in-plane refractive index of the polyimide film 17a are as follows, and the difference between the refractive indices is 0.01.

N ₁ = 1.53 n ₂ = 1.52 Therefore, by setting W ₂ −W ₁ = 3.9 μm, the fabrication error can be adjusted.

Therefore, here, w ₂ = 16.0 μm w ₁ = 12.1 μm was set.

In the processing method shown in FIG. 9, the absolute accuracy of the film thickness can be only about ± 0.5 μm.
Since the relative difference in film thickness can be processed with a thickness of 0.05 μm, the production error can be accurately adjusted.

FIG. 11 shows the change in the light transmittance of the manufactured 2 × 2 optical switch with respect to the electric power applied to the thin-film heater. P ₁ is 0, switching, the on-off operation in whether to apply a 400 mW.

When a groove having a width of 20 μm is formed and a film and an adhesive are inserted therein, excess loss of light is 0.3 dB.
Met. This value is sufficiently smaller than the value of the entire optical circuit, and does not pose a practical problem.

(Embodiment 2) FIG. 12 shows an arrayed waveguide grating type wavelength multiplexer / demultiplexer according to a second embodiment of the present invention.

In FIG. 12, reference numeral 13 denotes a silicon substrate,
Is a groove, 17 is a phase adjustment plate, 19 is a cladding layer, 20 is an input waveguide, 21 is an output waveguide. 22 is a slab waveguide, 2
Reference numeral 3 denotes each of the arrayed waveguides. FIG. 13 is an enlarged view of the phase adjustment plate used in FIG.

In this embodiment, the error in the optical path length of the arrayed waveguides 23 arranged in parallel can be measured using a low coherent light source.

Regarding this measuring method, see K. Takada et al.,
"Measurement of phase error distributions in sili
ca-based arrayed-waveguide grating multiplexers by
using Fourier transform Spectroscopy, "Electron.Le
tt., vol. 30, no. 20, pp. 1671-1672, 1994.

The procedure for manufacturing the wavelength multiplexing / demultiplexing device of this embodiment is described below.

The basic procedure is the same as in the first embodiment.

According to the prior art, the silicon substrate 13
An arrayed waveguide grating wavelength multiplexer / demultiplexer is fabricated by fire deposition and reactive ion etching.

A groove 16 having a width of 20 μm and a depth of 150 μm is processed by a dicing saw. The groove 16 is filled with an adhesive having a refractive index of n ₂ .

In this state, the error in the optical path length of the arrayed waveguides 23 arranged in parallel is measured and obtained.

The polyimide film having the in-plane refractive index n ₁ is processed by a processing method as shown in FIG. 9 so that the film thickness becomes w ₁ , w ₂ ... W _N.

[0095] In this case, each film thickness of the w _1, w ₂ ·· w _N is,
The optical path length error of the arrayed waveguide 23 is determined to be adjusted. For example, if the optical path length error is δL ₁ ... ΔL _{N in the first} , second,.

[0096]

[Number 1] _{δL i + (n 1 -n 2} ) × wi = defines the w _i so as to be constant.

Finally, the processed phase adjustment plate 17 is
6 and fixed with an adhesive.

FIG. 14 shows the transmission wavelength characteristics of the arrayed waveguide grating type wavelength multiplexing / demultiplexing device before the phase adjusting plate is inserted, and FIG. 15 shows the arrayed waveguide grating type wavelength multiplexing / demultiplexing device after the phase adjusting plate is inserted by the above process. 3 shows the transmission wavelength characteristics of the duplexer.

The optical path length error of the arrayed waveguide is adjusted by inserting the phase adjusting plate, and the crosstalk is reduced from −30 dB to −.
It has been improved to 40 dB. At this time, the excess loss of the phase adjustment plate insertion including the groove processing was 0.3 dB.

In Examples 1 and 2, each material was selected such that the difference between the in-plane refractive index of the phase adjusting plate and the refractive index of the adhesive was 0.01. In this case, 0.
The change in the film pressure required to adjust the optical path length error of 1 μm is 10 μm, and the film thickness processing accuracy of the phase adjustment plate is ± 10%.
Even if it was 0.5 μm, the optical path length error could be adjusted with an accuracy of ± 0.005 μm.

Incidentally, by setting the refractive index difference between the adhesive and the film to an arbitrary value, it is possible to adjust the ratio of the change in the film thickness to the optical path length.

(Embodiment 3) FIG. 16 shows an arrayed waveguide wavelength multiplexer / demultiplexer according to a third embodiment of the present invention.

In FIG. 16, reference numeral 20 denotes an input waveguide, 21 denotes an output waveguide, 22 denotes a slab waveguide, 23 denotes an array waveguide, 19 denotes a cladding layer, 13 denotes a silicon substrate, 16 denotes a groove, and 27 denotes amplitude adjustment. Each plate is illustrated.

FIG. 17 is an enlarged sectional view taken along line AA in FIG. FIG. 18 is an enlarged view of the amplitude adjusting plate used in FIG.

In this embodiment, after a groove 16 having a constant width intersecting on the array waveguide of the array waveguide type optical multiplexer / demultiplexer is processed, the in-plane absorptance whose thickness has changed spatially has a constant amplitude adjustment. A plate 27 is inserted into the groove 16.

Further, in order to fix the amplitude adjusting plate 27 in the groove 16, an optically transparent adhesive 28 is filled as shown in FIG. Here, the refractive index of the adhesive 28 was set to be the same as the refractive index of the amplitude adjusting plate 27 so as not to change the phase characteristics.

Here, assuming that the film thickness at the portion crossing the i-th array waveguide is W _i , the amplitude A _i of the light propagating through the i-th array waveguide after passing through the groove 16 is:

[0108]

## EQU2 _{## It} changes by A _i ² = exp (−αW _i ).

Here, α is the in-plane absorption coefficient of the amplitude adjusting plate 27. Here, certain losses that occur when a transparent film is inserted are excluded. This relationship is Lambert's law for light absorption, and can be applied when the absorption coefficient is constant with respect to the film thickness.

Therefore, in this embodiment, the amplitude is adjusted by appropriately giving the in-plane absorption coefficient α and the film thickness W _i of the film.

First, the input waveguide 20, the output waveguide 21,
The distribution of the amplitude error of a plurality of paths formed by the slab waveguide 22 and the array waveguide 23 is measured. For this measuring method, a known optical circuit analyzing method using a low coherent light source can be applied (for example, see Japanese Patent Application No. 6-5899).

The procedure for manufacturing the wavelength multiplexing / demultiplexing device of this embodiment is described below.

1) An array waveguide type wavelength multiplexer / demultiplexer is manufactured on the silicon substrate 13 by a flame deposition method and a reactive ion etching method.

2) The input waveguide 20, the output waveguide 21,
The distribution of the phase error and the amplitude error of a plurality of paths formed by the slab waveguide 22 and the array waveguide 23 is measured using a low coherent light source. Based on this measurement,
The amplitude adjustment amounts A ₁ , A ₂ ,... A _N (A _i ≦ 1: the subscript is the number of the arrayed waveguide) are determined.

3) Each arrayed waveguide was irradiated with a laser beam to partially change the refractive index and adjust the phase error.

[0116] 4) the polyimide film (absorption coefficient alpha: to produce a refractive index n _1), the thickness w ₁ at the intersection with array waveguide during insertion, w _2, such that · · · w _N , Process.

Where w _i is

[0118]

## EQU3 _{## It} is determined that A _i ² = exp (−αW _i ).

5) A groove 16 having a width W ₀ and a depth of 150 μm is formed using a dicing saw.

6) Insert the amplitude adjusting plate 27 into the groove 16 and fix it with the adhesive 28.

The second harmonic of a mode-locked Q-switched YAG laser was used to reduce the phase error in this embodiment.

In the amplitude adjustment, an absorption coefficient of 0.02
(1 / [mu] m), to prepare a film having a thickness of 30 microns, by a dicing saw, to process the film thickness w _i of 0.5 micron accuracy to 0-20 microns. The width w _{0 of the} groove 16 is
35 microns.

FIG. 19 shows the transmission wavelength characteristics of the arrayed waveguide grating type multiplexer / demultiplexer before the amplitude adjusting plate is inserted (after the phase error is reduced). FIG. 20 shows the array after the amplitude adjusting plate is inserted by the above method. The transmission wavelength characteristics of the waveguide grating type multiplexer / demultiplexer are shown.

As shown in FIG. 20, the amplitude adjusting plate 27
Adjusted the amplitude error of the array waveguide, and the crosstalk was improved from -40 dB to -50 dB. At this time, the excess loss of the amplitude adjustment plate insertion including the groove processing is 1.
7 dB.

(Embodiment 4) FIG. 21 shows an arrayed waveguide type wavelength multiplexer / demultiplexer according to a fourth embodiment of the present invention. FIG.
Reference numerals 16-1 and 16-2 denote grooves, 27-1 a phase adjustment plate, and 27-2 an amplitude adjustment plate.

In this embodiment, a groove 16-1 having a constant width crossing the array waveguide of the conventional arrayed waveguide type optical multiplexer / demultiplexer.
After processing, a phase adjusting plate 27-1 having a constant in-plane refractive index having a spatially changed thickness is inserted into the groove 16-1, and further, an adhesive is filled. This configuration is for reducing the phase error.

Further, similarly to the third embodiment, a groove 16-2 having a constant width intersecting the array waveguide of the arrayed waveguide type optical multiplexer / demultiplexer is processed, and the amplitude adjusting plate 27-2 is mounted on the groove 16-2.
Inserted in 2. The present embodiment differs from the third embodiment in that the amplitude adjusting plate 27-2 to be inserted has a flattened thickness as shown in FIG.

In FIG. 22, reference numeral 31 denotes a film whose thickness varies spatially and has a constant in-plane absorptivity, and reference numeral 32 denotes a transparent material which fills the irregularities. Here, a transparent material 32 is used to fill the irregularities.
Is the same as the refractive index of the film 31.

An adhesive is filled to fix the amplitude adjusting plate 27-2 in the groove. However, since the amplitude adjusting plate used in the fourth embodiment is filled with the unevenness, the third embodiment is used.
As in the above case, the refractive index of the adhesive does not need to be the same as the refractive index of the amplitude adjusting plate. The procedure for manufacturing the wavelength multiplexing / demultiplexing device of the present embodiment will be described below.

1) An array waveguide type wavelength multiplexer / demultiplexer is formed on a silicon substrate 13 by a flame deposition method and a reactive ion etching method.

2) The input waveguide 20, the output waveguide 21,
The distribution of the phase error and the amplitude error of a plurality of paths formed by the slab waveguide 22 and the array waveguide 23 is measured using a low coherent light source. Based on this measurement,
The amplitude adjustment amounts A ₁ , A ₂ ,... A _N (A _i ≦ 1: the subscript is the number of the arrayed waveguide) are determined.

3) The phase adjusting plate 27-1 is inserted into the groove 16-1 by the optical circuit with the phase adjusting plate and the manufacturing method thereof shown in the first and second embodiments to reduce the phase error.

[0133] 4) the polyimide film (absorption coefficient alpha: to produce a refractive index n _1), the thickness w ₁ at the intersection with array waveguide during insertion, w _2, such that · · · w _N , Process.

Where w _i is

[0135]

## EQU4 _{## It} is determined that A _i ² = exp (−αwi).

5) A groove 16-2 having a width w ₀ and a depth of 150 μm is formed using a dicing saw.

6) Insert the amplitude adjusting plate 27-2 into the groove 16-2 and fix it with an adhesive.

In practice, the absorption coefficient is 0.03 (1 / μ
m), to prepare a film having a thickness of 20 microns, by a dicing saw, to process the film thickness w _i of 0.5 micron accuracy from 0 to 15 microns. Thereafter, a transparent material 32 having the same refractive index as the produced film 31 was spin-coated on the film. By the spin coating, the formed grooves were filled, and the film thickness became 22 μm (constant value) throughout. The width w ₀ of the groove was 25 microns.

The amplitude error of the array waveguide was adjusted by the amplitude adjusting plate, and the crosstalk was improved from 40 dB to −50 dB except for adjacent channels. At this time,
The excess loss of inserting the phase adjustment plate and the amplitude adjustment plate including two groove processing was 2.2 dB.

(Embodiment 5) The structure of a fifth embodiment of the present invention is the same as that of the fourth embodiment.

The difference from the fourth embodiment is that an amplitude adjusting plate as shown in FIG. 23 is inserted. In FIG. 23, reference numeral 33 indicates a transparent film, and reference numeral 34 indicates a metal film. The thickness of each metal film 34 is determined by the metal absorptance and the amplitude adjustment amount. In the case of the metal film 34, since the absorption coefficient is large, the required film thickness is small, and the influence of the unevenness of the metal film on the phase is small.

In this embodiment, the amplitude characteristic of the arrayed waveguide grating type wavelength multiplexer / demultiplexer, which can be generally approximated by a Gaussian type, is represented by si.
It was adjusted to an nc function. Further, the phase adjustment is performed to realize a negative value in the sinc function, that is, the phase is set to 180.
Used to stagger.

The actual amplitude adjusting film was prepared by forming a film having a thickness of 15 μm and vapor-depositing Cr. Also, the width w of the groove
₀ is 20 microns.

FIGS. 24, 25 and 26 show amplitude characteristics, phase characteristics and transmission wavelength characteristics before and after the adjustment. By adjusting the amplitude and phase characteristics and realizing a sinc function-like distribution, the passband is flattened and 3d
The B bandwidth could be increased by about 280%.

At this time, the excess loss of the insertion of the amplitude adjusting plate including the groove processing was 3.5 dB.

(Embodiment 6) FIG. 27 shows a 1 × 8 splitter with an amplitude adjusting plate as a sixth embodiment of the present invention.

In FIG. 27, reference numeral 35 denotes an input waveguide, 36 denotes a slab waveguide, 37 denotes an output waveguide, 16 denotes a groove, and 27 denotes an amplitude adjusting plate. The input waveguide is designed to be a single-mode waveguide, and has a Gaussian-type approximable intensity distribution. The input light spreads in the slab waveguide and is coupled into the output waveguide. The distribution of the optical power at the output section of the slab waveguide is obtained by Fourier-transforming the distribution at the input section of the slab waveguide. Since the distribution of the input portion of the slab waveguide is substantially Gaussian, the distribution of the output portion can be approximated to be substantially Gaussian. Generally, the 1 × N splitter is designed so that the opening width of the output waveguide becomes wider from the center to the outside in order to make the optical power guided to the N output waveguides the same. Actually, as shown in FIG. 28, the optical power distribution at the output portion of the slab waveguide is calculated by simulation, and the optical power coupled to each output waveguide becomes the same.
That is, the area S _i separated by vertical lines in FIG. 28 (i is an output port number) so that the same opening width x _i are determined.

Generally, in a 1 × N splitter actually manufactured, the distribution of the optical power in the input waveguide is not completely Gaussian, or the loss at the coupling portion between the slab waveguide and the output waveguide varies. For this reason, there is a variation in output optical power between ports.

In the present embodiment, in a 1 × 8 splitter made of a silica-based optical waveguide, variation in output light power between ports is reduced by using the amplitude adjusting plate 27.

The procedure for manufacturing the 1 × 8 splitter of this embodiment is described below.

1) The power of the light output from the eight output waveguides of the 1 × 8 splitter was measured. FIG. 29 shows the output port dependence of the measured output light power. Loss is 1
It was distributed between 1.8 and 12.6 dB. The amplitude adjustment amount for reducing this variation was determined as follows. The difference between the maximum loss of 12.6 dB and the loss of each output port was calculated, and the square root of the value was used as the amplitude adjustment amount A _i (i is the output port number). FIG. 30 shows the output port dependence of the determined amplitude adjustment amount. The maximum adjustment amount is 0.8 dB in loss,
That is, since it was 0.83, the maximum amplitude adjustment amount was
0.83 = 0.91.

2) For a film thickness of 10 μm, 0.9
The absorption coefficient α of the material of the amplitude adjustment plate is set to 0.021 (1) so that the amplitude adjustment of (<maximum amplitude adjustment amount 0.91) can be obtained.
/ Μm). The amplitude adjustment plate in this embodiment is
As shown in FIG. 30, an absorption film is formed on a transparent film, and the absorption is changed by the cut amount (cut-off amount) into the absorption film. The transparent film was used to reduce the amount of cut-off of the absorbing film and reduce excess loss while maintaining the strength and operability of the amplitude adjusting plate sufficiently. The thicknesses of the absorbing film and the transparent film were set to 10 μm and 8 μm, respectively. The cut amount in the absorption film portion was determined such that the cut-off amount W _i satisfied the following equation.

[0153]

A _i ² = exp (−α · W _i ) (1) FIG. 31 shows the distribution of the cut amount of the determined amplitude adjustment plate. The maximum depth of cut was 10 μm giving the minimum adjustment.

3) FIG. 32 shows a process of manufacturing an actual amplitude adjusting plate. First, a transparent film 62 having a thickness of 8 μm is formed on a Si substrate 61 by a spin coating method, and after drying, an absorption coefficient α = 0.021 (1
/ Μm) and an absorption film 63 having a thickness of 10 μm was formed by spin coating. Thereafter, the dicing saw 64 was used to make cuts of the amount determined by the above-described method. 1
Since the distance between adjacent output waveguides of the × 8 splitter was 250 μm, the width of the blade of the dicing saw was 100 μm. After making the cuts, cut the film into strips on the Si substrate,
The amplitude adjusting plate 27 was peeled off with tweezers 65.

4) A groove 13 having a width of 20 μm, which traverses all eight output waveguides of the 1 × 8 splitter, was formed using a dicing saw. Using a manipulator with tweezers, the fabricated amplitude adjustment plate was inserted into the groove, and the cutout was cut into the amplitude adjustment plate and the position was adjusted so that the output waveguide intersected. Further, an adhesive having the same value as the refractive index of the amplitude adjusting plate was injected into the gap between the amplitude adjusting plate 27 and the groove 16 using a micropipette, and then fixed by irradiating ultraviolet rays.

FIG. 33 shows the distribution of optical power at each output port after adjustment. 11.8-12.
The loss distributed at 6 dB is 12.8 to 12.9 dB.
And the variation was reduced. The excess loss of 0.3 dB on average is mainly due to the width 2
Due to diffraction loss at 0 μm groove. The above results
Although the description is for the TE mode, the adjustment was almost the same in the TM mode.

(Embodiment 7) FIG. 34 shows an arrayed waveguide grating type wavelength multiplexer / demultiplexer with a phase adjusting plate according to a seventh embodiment of the present invention. In FIG. 34, reference numeral 20 denotes an input waveguide, 21 denotes an output waveguide, 22 denotes a slab waveguide, 23 denotes an array waveguide,
19 is a cladding layer, 13 is a silicon substrate, 16 is a groove, 2
Reference numeral 7 denotes a phase adjusting plate. FIG. 35 shows FIG.
The enlarged sectional view which follows the BB line in the inside is shown. Further, FIG.
34 shows an enlarged view of the phase adjustment plate used in FIG.

The array waveguide type optical multiplexer / demultiplexer of this embodiment is
A phase adjusting plate 17 is inserted into a groove 16 having a constant width formed so as to cross all array waveguides.

Further, a gap between the phase adjusting plate 17 and the inner wall of the groove 16 is filled with an adhesive 18, and the optical circuit and the phase adjusting plate are fixed.

In this embodiment, the shift of the wavelength order of the optical path length of the array waveguide in the arrayed waveguide grating type wavelength multiplexer / demultiplexer made of the silica-based optical waveguide, that is, the phase error is reduced by using the phase adjusting plate 17. did. The fabricated arrayed waveguide grating has 8 input / output ports, 30 arrayed waveguides, and a channel wavelength interval of 0.8 nm.

The procedure for manufacturing the wavelength multiplexer / demultiplexer of this embodiment is described below.

1) The phase and amplitude characteristics of light passing through each array waveguide constituting the array waveguide grating were measured.
For this measurement, a known optical circuit breaking method using low coherence light was applied (for example, Japanese Patent Application No. Hei 6-5989).
No.). FIG. 37 shows a measurement system. 41 is a light source, 42,
43 is an optical fiber 3 dB coupler, 44 is an interference type optical circuit for measurement, 45, 46, and 49 are lenses, 47 is a prism,
48 is a reflector, 51 and 52 are emission ports of the coupler 42, 53 and 54 are incidence ports of the coupler 43, 50 is a narrow line width laser, 55 is a dichroic mirror, and 56 and 5
7, a photodetector; 58, a fringe counter; 59, a waveform recorder.

As the light source 51, SLD light having a coherence length of 35 μm and a band of 1.55 μm was used. Narrow linewidth laser 50
A DFB laser having a wavelength of 1.3 μm was used. SL
The D light and the DFB laser light are split into two optical paths by a 3 dB coupler 42, one of which is connected to an optical circuit to be measured.
The other is guided to an optical path length variable section including a reflector 48 installed on an electric stage. Light from the two optical paths is again coupled by the 3 dB coupler 43. The 1.3 μm and 1.55 μm lights emitted from the interferometer are separated by a dichroic mirror 55, and the 1.3 μm light is received by a photodetector 56, and the 1.55 μm light is received by a photodetector 57. . Using the fact that the beat signal of the light from the laser 50 changes by a half cycle when the optical path length in the interferometer changes by a half wavelength, the fringe counter 58 generates a clock pulse every time the optical path length changes by a half wavelength. Using the pulse as an external clock, the waveform recorder 59 samples the interference signal. In this configuration, the two lights interfere with each other only when the optical path length difference between the path passing through the optical circuit and the path passing through the optical path length variable unit is shorter than the coherence length of the light source, and an interference signal is observed. Since the array waveguides are designed so that the optical path lengths are sequentially increased by ΔL, when the optical path length of the optical path length variable section is increased, interference signals are obtained in order from the shorter array waveguides.

FIG. 38 shows an example of the observed interference signal. Since the coherence length of the light source is sufficiently smaller than ΔL = 254 μm, the interference signal can be separated into fringes as indicated by broken lines in FIG. Since each fringe represents a transfer function of light passing through each arrayed waveguide, information on the phase and amplitude of light can be obtained by mathematical processing such as discrete Fourier transform. By performing the same processing for all the fringes, the phase and amplitude distributions for all the arrayed waveguides can be obtained. FIG. 39 and FIG.
0 indicates the distribution of the phase and the amplitude at the transmission center wavelength of each array waveguide. FIG. 41 shows a transmission wavelength characteristic from the input port number 8 to the output port number 9. The crosstalk was at most 25 dB, largely due to the phase error distributed between 0.3 and 0.25 radians.

2) The amount of phase adjustment for reducing the phase error was determined as follows. First, the configuration of the phase adjustment plate 27 in the present embodiment was determined to be a film having a constant film thickness and a cut formed according to the amount of phase adjustment (FIG. 36). Further, in the present embodiment, the refractive index of the adhesive 28 is smaller than the refractive index of the phase adjusting plate, and the amount of phase adjustment is set to a negative value.

As can be seen from FIG. 39, the phase error is T
E mode and TM mode are slightly different. Therefore, the phase adjustment amount was calculated on the assumption that the phase error was the average value of the TE mode and the TM mode. Since the maximum value of the phase adjustment amount is 0.32 FUJAN, the refractive index difference between the phase adjusting plate and the adhesive is set to 0 so that the phase of 0.32 radian = 0.08 μm can be adjusted with a cut of about 7 μm. .011. From this refractive index difference, the cut amount corresponding to each phase adjustment amount was determined. FIG. 42 shows the distribution of the determined cut amount in the phase adjustment plate.

3) FIG. 43 shows a process of manufacturing a phase adjusting plate.

First, a film having a thickness of 15 μm was formed by spin coating.
m is formed on the Si substrate 61, and after drying, a cut is made using the dicing saw 64 in an amount determined by the above-described method. The minimum adjacent array waveguide interval is 120 μm.
m, the width of the blade of the dicing saw was 60 μm. After making the cuts, cut the film into strips on the Si substrate,
The phase adjustment plate was peeled off with tweezers 65.

4) A groove 16 having a width of 20 μm, which traverses all 30 output waveguides of the arrayed waveguide grating, was formed using a dicing saw. Using a manipulator with tweezers in the groove, insert the prepared phase adjustment plate,
The position was adjusted so that the cut-making part of the phase adjustment plate and each array waveguide intersected. Further, using a micropipette, an adhesive having a refractive index smaller than the refractive index of the phase adjustment plate by 0.011 is injected into the gap between the phase adjustment plate 17 and the groove 16, and then irradiated with ultraviolet rays. Fixed.

FIG. 44 shows the transmission wavelength characteristics of the arrayed waveguide grating type multiplexer / demultiplexer after the phase adjusting plate is inserted. FIG. 45, FIG.
Is a graph showing the phase error and the amplitude distribution after the phase adjustment, respectively. The phase error of the array waveguide is adjusted by the phase adjustment plate. The crosstalk is -25d before adjustment
From B to -37dB in TE mode, -39d in TM mode
B improved. At this time, the excess loss due to the groove processing and the phase adjustment plate insertion was 1.0 dB. The average phase error of the TE / TM mode has a standard deviation of 0.088 to 0.8.
036 has been reduced. Since the amplitude distribution is almost the same as before the phase adjustment plate is inserted, it is understood that the influence of the phase adjustment plate on the amplitude is small, and only the phase can be adjusted almost independently.

(Eighth Embodiment) FIG. 47 shows an array waveguide type wavelength multiplexer / demultiplexer with a phase adjusting plate and an amplitude adjusting plate according to an eighth embodiment of the present invention. In FIG. 47, reference numerals 16-1 and 16-2 denote grooves, reference numerals 27-1 and 27-2 denote phase adjustment plates and amplitude adjustment plates, respectively.

The array waveguide type optical multiplexer / demultiplexer of this embodiment is
A phase adjusting plate 27-1 and an amplitude adjusting plate 27-2 are inserted into grooves 16-1 and 16-2 having a constant width, which traverse all array waveguides. Is filled and fixed with an adhesive.

In this embodiment, the phase error and the amplitude error in the arrayed-waveguide grating-type wavelength multiplexer / demultiplexer made of a silica-based optical waveguide are measured using the phase adjustment plate 27-1 and the amplitude adjustment plate 27-2, respectively. Reduced. The fabricated arrayed waveguide grating has 16 input / output ports, 64 arrayed waveguides, and a channel wavelength interval of 0.8 nm.

The procedure for manufacturing the wavelength multiplexing / demultiplexing device of this embodiment is described below.

1) Two grooves having a width of 25 μm and a depth of 120 μm traversing all the arrayed waveguides were formed by using a reactive ion etching method. The distance between the two grooves is 100
μm. 48 and 49 show phase and amplitude distributions in the TE mode measured using a low coherence interferometer after the groove is formed. FIG. 50 shows a transmission wavelength characteristic in the TE mode. Crosstalk is -29d
B, the main cause of which is phase error.

2) The phase adjusting plate of the present embodiment is different from the phase adjusting plate of Embodiment 7 in that the concave portion of the film having the same configuration as the phase adjusting plate is flattened using a transparent material having a different refractive index. did. The configuration is shown in FIG. The amount of cut into the phase adjusting plate was determined in the same manner as in Example 7. In the determination, the maximum cutting depth and the refractive index difference between the two substances constituting the phase adjusting plate were 7 μm and 0.0 μm, respectively.
It was set to 15.

FIG. 52 shows a step of manufacturing the phase adjusting plate of this embodiment. First, a film 68 having a concave portion having the same configuration as that of Example 7 was manufactured by milling using a diamond tool 71 rotated. continue,
The concave portions were flattened by spin-coating a transparent material 69 having a different refractive index by 0.015. The thickness of the first film 66 and the final phase adjustment plate 70 are each 15 μm,
It was 20 μm.

3) The prepared phase adjusting plate 27-1 was inserted into the groove 16-1, and was fixed to the groove using an ultraviolet curing adhesive. At this time, since the phase adjusting plate is flattened so that the phase can be adjusted only by inserting it into the groove, it is not necessary to strictly set the refractive index of the adhesive. Therefore, the refractive index of the adhesive was set to 1.47, which is almost the same as the refractive index of the core. Making the refractive index values of the adhesive and the core substantially the same helps to reduce the diffraction loss in the grooves and to reduce the influence of the groove width distribution on the phase error.

4) The distribution of the phase and the amplitude after inserting the phase adjusting plate was measured by using the low coherence interferometry. FIG.
3. FIG. 54 shows measured phase and amplitude distributions in the TE mode. FIG. 55 shows a transmission wavelength characteristic in the TE mode. As a result of reducing the maximum value of the phase error from 0.45 radians to 0.05 radians, the crosstalk becomes −
It improved from 29 dB to -39 dB. Also, the TM mode phase error is reduced at the same time, and the crosstalk is -39d.
B or less. Since the crosstalk of −39 dB was caused by the deviation of the amplitude distribution from the Gaussian distribution, the amplitude adjusting plate 27-2 was manufactured next.

In the amplitude adjusting plate of this embodiment, the concave portion of the film having the same configuration as that of the amplitude adjusting plate of Embodiment 6 has the same refractive index as the absorbing film and is made of a transparent material. A flattened one was used. The reason why the refractive index of the material for filling the concave portion is the same as the refractive index of the absorbing film is that a phase error is not caused by the amplitude adjusting plate. The reason why the material for filling the concave portion is a transparent material is that the material does not change the absorption.

5) The cut amount in the amplitude adjusting plate was determined by the following method. First, the measured amplitude distribution (FIG. 54)
Is fitted as a Gaussian distribution, and the path number and the peak value whose distribution has the peak value and the value is 1 / e of the peak value
Is obtained. In this embodiment, the amplitude adjustment causes a loss. That is, since the adjustment amount is a value smaller than 1, the peak value is reset so that the fitting curve falls below all the amplitude values (broken line in FIG. 54). The fitting curve obtained in this way becomes the final set value of the amplitude. The amplitude adjustment amount A _i (i is a pass number) is determined from the ratio between the amplitude setting value after the adjustment and the amplitude value before the adjustment. FIG. 56 shows the distribution of the determined amplitude adjustment amount. The amplitude adjustment amount was distributed from 1.0 to 0.92. 6) Next, processing data of the amplitude adjustment plate was obtained. First,
The absorption coefficient a of the material of the amplitude adjustment plate was determined to be 0.021 (1 / μm) so that an amplitude adjustment of 0.90 (<the maximum amplitude adjustment amount 0.92) was obtained for a film thickness of 10 μm. . The amount of cut into the absorbing film portion was determined so that the amount of cut W _i satisfies the expression (1). FIG. 57 shows the distribution of the determined cut amount in the amplitude adjustment plate. The maximum depth of cut was 10 μm giving the minimum adjustment.

7) FIG. 58 shows a step of manufacturing the phase adjusting plate of this embodiment. First, a film 72 having a concave portion having the same configuration as in Example 6 was formed by milling, and then a transparent substance 73 was spin-coated to flatten the concave portion. The thicknesses of the first transparent film 62, the absorbing film 63 and the final amplitude adjusting plate 74 are 8 μm and 10 μm, respectively.
m and 22 μm.

8) The prepared amplitude adjusting plate was inserted into the groove 16-1, and was fixed to the groove using an ultraviolet curing adhesive. At this time, so that only the amplitude can be adjusted without a phase error,
Since the amplitude adjusting plate is flattened, it is not necessary to set the refractive index of the adhesive strictly to the same value as that of the amplitude adjusting plate. Therefore, the refractive index of the adhesive is approximately the same as the refractive index of the core, 1.4.
7 was set. Making the refractive index values of the adhesive and the core substantially the same helps to reduce the diffraction loss in the groove and to reduce the influence of the groove width distribution on the phase error.

FIGS. 59 and 60 show the TE after the amplitude adjustment plate is inserted.
The amplitude distribution and transmission wavelength characteristics in the mode were shown.

The amplitude error was reduced to a standard deviation of 0.02, and the crosstalk was improved to -48 dB.
At this time, the phase error did not change greatly before and after the insertion of the amplitude adjusting plate, and only the amplitude was adjusted without affecting the phase characteristics. The characteristics of the TM mode were almost the same as those of the TE mode, and both the phase and the amplitude could be adjusted without causing polarization dependence of the error.

As described above, by providing the phase adjustment plate and the amplitude adjustment plate, the crosstalk of the arrayed waveguide type optical wavelength multiplexer / demultiplexer was greatly improved from -29 dB to -48 dB. At this time, the excess loss of inserting the phase adjustment plate and the amplitude adjustment plate including the groove processing was 1.7 dB.

(Embodiment 9) A ninth embodiment of the present invention is an arrayed waveguide type wavelength multiplexer / demultiplexer with an amplitude / phase adjusting plate. The configuration is the same as that of the seventh embodiment, except that an amplitude / phase adjusting plate (optical characteristic adjusting plate) 98 as shown in FIG. 61 is inserted instead of the phase adjusting plate 27. FIG.
Reference numeral 80 denotes a transparent film having a uniform refractive index, and 81 denotes a metal film. A projection 82 is formed on the transparent film 80, and the phase is adjusted by changing the thickness of the projection. On the other hand, each metal film 81 is used for changing the absorption coefficient and adjusting the amplitude of light by changing its thickness. The thickness of each metal film is determined by the absorption rate of the metal and the amplitude adjustment amount. In the case of a metal film, the required film thickness is small because the absorption coefficient is large, and the influence of the difference in the thickness of the metal film on the phase is small. That is, the thickness of the projection 82 used for phase adjustment is determined independently of the thickness of the metal film.

In this embodiment, in an arrayed waveguide grating type wavelength multiplexer / demultiplexer made of a silica-based optical waveguide, the amplitude retention of light passing through each arrayed waveguide, which can be generally approximated by a Gaussian type, is represented by a sinc function. Was adjusted. The phase adjustment is to achieve a negative value in the sinc function, ie, to set the phase to 18
Used to change 0 degrees.

In this embodiment, the phase error and the amplitude error in the arrayed-waveguide grating type wavelength multiplexing / demultiplexing device made of the silica-based optical waveguide are reduced by using the amplitude / phase adjusting plate 98, respectively. The fabricated arrayed waveguide grating has 8 input / output ports, 64 arrayed waveguides, and a channel wavelength interval of 0.8.
nm.

The procedure for manufacturing the wavelength multiplexing / demultiplexing device of this embodiment is described below.

1) A groove having a width of 25 μm and a depth of 120 μm traversing all the arrayed waveguides was formed by using a reactive ion etching method. Next, the distribution of phase and amplitude was measured using a low coherence interferometer. FIG. 62, FIG.
3. FIG. 64 shows the amplitude distribution, phase distribution, and transmission wavelength characteristics before and after the insertion of the amplitude / phase adjusting plate.

2) The amount of amplitude / phase adjustment necessary for adjusting the transmittance of light passing through each array waveguide in a sinc function was determined, and the processing data of the amplitude / phase adjusting plate was determined. The thickness of the metal film and the thickness of the convex portion of the transparent film are:
It was determined in the same manner as in Examples 6 and 7.

3) Based on the determined processing data, FIG.
In the process shown in FIG. 5, the amplitude / phase adjusting plate of this example was manufactured. First, a metal film 92 having a thickness of 30 μm was formed on a substrate 91, and the metal film was processed by etching using a mask 93 to form a concave mold. The processing depth was the same as the thickness of the convex portion of the transparent film determined in advance. Next, a polyimide film 95 was formed on the mold by spin coating. Further, a metal Cr film 96 having a locally changed thickness was formed on the film by a sputtering method. The prepared convex transparent film with metal film 97 was peeled off from the substrate 91 using tweezers,
This was cut into an amplitude / phase adjusting plate 98.

4) The manufactured amplitude / phase adjusting plate 98 is shown in FIG.
No. 4 was inserted into a groove having a width crossing the arrayed waveguide and aligned, and then fixed using an adhesive.

The phase and amplitude distribution after the insertion of the amplitude / phase adjusting plate,
As can be seen from the transmission wavelength characteristics (FIGS. 62, 63, and 64), since the transmission characteristic of the sinc function was realized, the passband was flattened, and the 3 dB bandwidth was reduced to about 280.
% Could be expanded. At this time, the excess loss of the amplitude adjustment plate insertion including the groove processing was 3.5 dB.

Although the above results are shown for the TE mode, the adjustment was almost unchanged in the TM mode.

(Embodiment 10) A tenth embodiment of the present invention is an arrayed waveguide type multiplexer / demultiplexer equipped with a phase adjusting plate and a birefringence adjusting plate. The configuration is the same as that of the eighth embodiment, except that a birefringence adjusting plate 27-3 shown in FIG. 66 is inserted instead of the amplitude adjusting plate 27-2. The birefringence adjusting plate includes TE and T propagating in the waveguide to be adjusted.
It is used for giving different phase changes to the two polarized lights of the M mode and making the amount of change different for each waveguide.

As shown in FIG. 39 of the seventh embodiment, the phase error of the arrayed waveguide grating wavelength multiplexer / demultiplexer generally has polarization dependence. This is caused by variations in birefringence in each waveguide. Example 1
In Nos. To 9, the influence of the phase error on the polarization was small. However, in an optical circuit having a large area occupied by the waveguide and having a large birefringence variation, the phase error between the two polarized waves cannot be eliminated simultaneously only by the phase adjusting plate.

In this embodiment, in the arrayed waveguide grating type made of a silica-based optical waveguide, the phase error of one polarization in the compounding / demultiplexer is reduced by the phase adjusting plate 27-1, and the remaining polarization is further reduced. The phase error of each wave is adjusted by the birefringence adjusting plate 27
-3. The fabricated arrayed waveguide grating is
The number of input / output ports is 16, the number of array waveguides is 64, and the channel wavelength interval is 0.08 nm.

The procedure for manufacturing the wavelength multiplexing / demultiplexing device of this embodiment is described below.

1) A groove having a width of 25 μm and a depth of 120 μm traversing all the arrayed waveguides was formed using a dicing saw. Next, using a low coherence interferometer, T
The distribution of the phase and the amplitude of the E mode was measured. Phase error is 3
It is distributed in the range of 60 degrees, and the crosstalk is -5 dB
Met. Subsequently, in the same manner as in Example 7, only the phase error for the TE mode was reduced using the phase adjustment plate. The transmission characteristic after the phase adjustment is -32d in the TE mode.
B, -20 dB in the TM mode.

2) To reduce only the TM mode phase error, a birefringence adjusting plate was manufactured. Birefringence adjusting plate, as shown in FIG. 66, with respect to the adjusting plate longitudinal direction and values vertical refractive index different _{n x, n y (n x} ≠ n y) to become birefringent plate, The recess is processed. First, the distribution of the phase and amplitude of the TM mode was measured using a low coherence interferometer. Then, the refractive index difference (n _y -n _x) and TM
From the phase error of the mode, the depth of the concave portion processed on the birefringence adjusting plate was calculated. Furthermore, the polyimide film prepared by spin-coating, by applying a force in one direction, n _y -
n _x = 0.035, was prepared birefringent film having a thickness of 20 [mu] m. Finally, a cut was made in the birefringent film actually produced by using a dicing saw to obtain a birefringence adjusting plate.

3) The prepared birefringence adjusting plate was inserted into a width transverse to the arrayed waveguide, and after positioning, the plate was fixed using an adhesive. Refractive index of the adhesive was an n _x same. This is to prevent the phase of the TE mode from changing.

The crosstalk after inserting the birefringence adjusting plate is T
Both of the E and TM modes were -32 dB. The phase error is
The TE mode was almost the same as the TM mode, and the phase error of the TE mode did not change. As described above, the polarization dependence of the phase error in the arrayed waveguide grating type multiplexer / demultiplexer can be reduced by the birefringence adjusting plate of this embodiment. As described above, in the embodiment of the present invention, the Mach-Zehnder interferometer type 2 ×
Reduction of power consumption in 2 switches, reduction of inter-port variation of output light in 1 × N splitter, improvement of crosstalk by reduction of phase error and amplitude error in arrayed waveguide grating type multiplexer / demultiplexer, and transmission by adjusting transmission characteristics As an example, the flattening of the region or the reduction of the polarization dependence of the phase error due to the reduction of the birefringence variation has been described.

However, the waveguide type optical circuit of the present invention whose optical characteristics are adjusted is the same as the 2 × 2 switch,
The present invention is not limited to the × N splitter and the arrayed waveguide grating type multiplexer / demultiplexer, but can be applied to all optical circuits having a plurality of waveguides. Therefore, from an optical circuit having no interference part such as a 1 × N splitter to an interference optical circuit such as a Mach-Zehnder type optical circuit and a transversal type filter, adjustment of optical characteristics such as phase, amplitude, birefringence, etc. Can be used for

In the embodiment, amplitude, phase, and birefringence are shown as examples of optical characteristics to be adjusted.
For example, the present invention can be applied to adjustment of other optical characteristics such as polarization and nonlinear constant.

Further, the present invention is not limited to the quartz-based waveguide shown in this embodiment, but can be applied to an optical circuit using LN or a polymer.

In the present embodiment, the example of processing using a dicing saw and milling using a diamond cutting tool are shown as examples of the unevenness processing of the adjusting plate. However, other processing methods such as processing by etching may be used. Good. Further, the present invention is not limited to the direct processing of the film, but may be an indirect processing such as a die processing as shown in the ninth embodiment.

The film may be formed by other methods such as physical vapor deposition such as vacuum deposition and sputtering, chemical vapor deposition, and liquid phase growth. It is not limited to the coating method.

The adjusting plate may be of any combination, such as the one having a concave portion, the one having a convex portion, or the flattened concave portion or convex portion shown in the embodiment.

[0211]

As described above, as described with the embodiment,
The Mach-Zehnder interferometer type 2 × 2 switch of the present invention in which the optical path length error is adjusted has lower power consumption than the conventional one. In addition, the array waveguide grating type wavelength multiplexer / demultiplexer in which the optical path length error is adjusted has a crosstalk reduced by -10 dB or more as compared with the conventional one. The crosstalk of the arrayed waveguide grating type multiplexing / separating device of the present invention in which the amplitude error is adjusted is -10 dB lower than that of the conventional device.
The above is a reduction. In the arrayed waveguide grating type multiplexer / demultiplexer in which the amplitude characteristics and the phase characteristics were adjusted to have a sinc function, the 3 dB width of the pass band could be increased by about 280%.

[Brief description of the drawings]

FIG. 1 shows a prior art Mach-Zehnder interferometer type 2 × 2 switch.

FIG. 2 is an enlarged sectional view taken along line II-II in FIG.

FIG. 3 is a graph showing a change in light transmittance with respect to power applied to a thin film heater of the Mach-Zehnder interferometer shown in FIG.

FIG. 4 is a circuit configuration diagram of an arrayed waveguide grating type wavelength multiplexer / demultiplexer.

5 is a transmission wavelength characteristic diagram from a center input port to a center output port of the arrayed waveguide grating type wavelength multiplexer / demultiplexer shown in FIG. 4;

FIG. 6 is a diagram showing a Mach-Zehnder interferometer type 2 × 2 optical switch as a first embodiment.

FIG. 7 is an enlarged sectional view taken along line VII-VII in FIG. 6;

FIG. 8 is an enlarged perspective view of a phase adjustment plate used in the first embodiment.

FIG. 9 is a diagram illustrating a method of manufacturing the phase adjusting plate used in the first embodiment.

10 is a graph showing a change in light transmittance with respect to electric power applied to a thin film heater before a phase adjusting plate is inserted in the Mach-Zehnder interferometer shown in FIG.

11 is a graph showing a change in light transmittance with respect to a power applied to a thin film heater after a phase adjusting plate is inserted in the Mach-Zehnder interferometer shown in FIG.

FIG. 12 is a perspective view of an arrayed waveguide grating type wavelength multiplexer / demultiplexer as a second embodiment.

FIG. 13 is a schematic diagram of a phase adjusting plate used in the second embodiment.

14 is a graph showing a transmission wavelength characteristic from a center input port to a center output port before inserting a phase adjustment plate in the arrayed waveguide grating type wavelength multiplexer / demultiplexer shown in FIG.

FIG. 15 is a graph showing a transmission wavelength characteristic from a center input port to a center output port after the phase adjusting plate is inserted in the arrayed waveguide grating wavelength multiplexer / demultiplexer shown in FIG.

FIG. 16 is a perspective view showing an arrayed waveguide grating type multiplexer / demultiplexer according to a third embodiment.

FIG. 17 is an enlarged view taken along line AA in FIG. 16;

FIG. 18 is an enlarged perspective view of an amplitude adjustment plate used in the third embodiment.

19 is a transmission wavelength characteristic diagram before inserting an amplitude adjustment plate in the arrayed waveguide grating type multiplexer / demultiplexer shown in FIG.

20 is a transmission wavelength characteristic diagram after an amplitude adjustment plate is inserted in the arrayed waveguide grating type multiplexer / demultiplexer shown in FIG.

FIG. 21 is a perspective view of an arrayed waveguide grating type multiplexer / demultiplexer according to a fourth embodiment.

FIG. 22 is an enlarged perspective view of an amplitude adjusting plate used in the fourth embodiment.

FIG. 23 is an enlarged perspective view of an amplitude adjusting plate used in the fifth embodiment.

FIG. 24 is a diagram illustrating an amplitude distribution before and after an amplitude adjustment plate and a phase adjustment plate are inserted in the arrayed waveguide grating type multiplexer / demultiplexer of the fifth embodiment.

FIG. 25 is a diagram illustrating a phase distribution before and after an amplitude adjustment plate and a phase adjustment plate are inserted in the arrayed waveguide grating type multiplexer / demultiplexer of the fifth embodiment.

FIG. 26 is a transmission wavelength characteristic diagram before and after insertion of an amplitude adjustment plate and a phase adjustment plate in the arrayed waveguide grating type multiplexer / demultiplexer of the fifth embodiment.

FIG. 27: 1 × 8 with amplitude adjusting plate according to a sixth embodiment of the present invention
It is a top view of a splitter.

FIG. 28 is a graph showing a power distribution at a slab waveguide output section obtained by simulation in the sixth embodiment.

FIG. 29 is a graph showing the output port dependence of the output light power measured in the sixth embodiment.

FIG. 30 is a graph showing the output port dependence of the amplitude adjustment amount determined in the sixth embodiment.

FIG. 31 is a graph showing the distribution of the cut amount into the amplitude adjustment plate determined in the sixth embodiment.

FIG. 32 is a diagram illustrating a manufacturing process of the amplitude adjusting plate according to the sixth embodiment.

FIG. 33 is a graph showing a distribution of optical power at each output port of the splitter after adjustment by the amplitude adjustment plate in the sixth embodiment.

FIG. 34 is a perspective view of an arrayed waveguide grating type wavelength multiplexer / demultiplexer with a phase adjusting plate according to a seventh embodiment of the present invention.

FIG. 35 is an enlarged sectional view taken along line BB of FIG. 34;

FIG. 36 is an enlarged perspective view of a phase adjusting plate used in the seventh embodiment.

FIG. 37 is a configuration diagram of a measurement system for measuring the phase and amplitude of light passing through the arrayed waveguide of the wavelength multiplexer / demultiplexer of the seventh embodiment.

FIG. 38 is a graph showing an example of an interference signal of the arrayed waveguide of the wavelength multiplexer / demultiplexer of the present embodiment observed by the measurement system of FIG. 37;

FIG. 39 is a graph showing a phase distribution at the transmission center wavelength of each array waveguide of the wavelength multiplexer / demultiplexer in the seventh embodiment.

FIG. 40 is a graph showing the amplitude distribution at the transmission center wavelength of each arrayed waveguide of the wavelength multiplexer / demultiplexer in the seventh embodiment.

FIG. 41 is a graph showing transmission wavelength characteristics from the input port number 8 to the output port number 9 of the wavelength multiplexer / demultiplexer of the seventh embodiment.

FIG. 42 is a graph showing the distribution of the cut amount into the phase adjustment plate determined in the seventh embodiment.

FIG. 43 is a view illustrating a process of manufacturing the phase adjustment plate in the seventh embodiment.

FIG. 44 is a graph showing transmission wavelength characteristics of an arrayed waveguide grating type multiplexer / demultiplexer after a phase adjusting plate is inserted in the seventh embodiment.

FIG. 45 is a graph showing a phase error of the multiplexer / demultiplexer after phase adjustment in the seventh embodiment.

FIG. 46 is a graph showing the amplitude distribution of the multiplexer / demultiplexer after phase adjustment in the seventh embodiment.

FIG. 47 is a perspective view of an arrayed waveguide-wave-combining duplexer with a phase adjustment plate and an amplitude adjustment plate according to the eighth embodiment.

FIG. 48 shows TE measured using a low coherence interferometer after forming a groove in the wavelength multiplexer / demultiplexer in the eighth embodiment.
6 is a graph showing a phase distribution in a mode.

FIG. 49 shows TE measured by using a low coherence interferometer after forming a groove in the wavelength multiplexer / demultiplexer in the eighth embodiment.
6 is a graph showing an amplitude distribution in a mode.

FIG. 50 is a graph showing transmission wavelength characteristics in the TE mode after grooves are formed in the wavelength multiplexer / demultiplexer in the eighth embodiment.

FIG. 51 is an enlarged perspective view of a phase adjusting plate used in the eighth embodiment.

FIG. 52 is a diagram showing a step of manufacturing the phase adjusting plate used in the eighth embodiment.

FIG. 53 is a graph showing the phase distribution of the wavelength multiplexer / demultiplexer after the phase adjusting plate is inserted into the groove of the wavelength multiplexer / demultiplexer in the eighth embodiment.

FIG. 54 is a graph showing the amplitude distribution of the wavelength multiplexer / demultiplexer after the phase adjusting plate is inserted into the groove of the wavelength multiplexer / demultiplexer in the eighth embodiment.

FIG. 55 is a graph showing transmission wavelength characteristics of the wavelength multiplexer / demultiplexer after the phase adjusting plate is inserted into the groove of the wavelength multiplexer / demultiplexer in the eighth embodiment.

FIG. 56 is a graph showing the distribution of the amplitude adjustment amount determined from the distribution of the measured amplitude values of the wavelength multiplexer / demultiplexer in the eighth embodiment.

FIG. 57 is a graph showing the distribution of the cut amount into the amplitude adjustment plate determined from the amplitude adjustment amount in the eighth embodiment.

FIG. 58 is a view showing a step of manufacturing the phase adjusting plate in the eighth embodiment.

FIG. 59 is a graph showing the amplitude distribution in the TE mode of the wavelength multiplexer / demultiplexer after the insertion of the amplitude adjusting plate in the eighth embodiment.

FIG. 60 is a graph showing the transmission wavelength characteristic in the TE mode of the wavelength multiplexer / demultiplexer after the amplitude adjusting plate is inserted in the eighth embodiment.

FIG. 61 is an enlarged perspective view of an amplitude / phase adjusting plate used in the ninth embodiment.

FIG. 62 is a graph showing the amplitude distribution of the multiplexer / demultiplexer before and after the amplitude / phase adjusting plate is inserted into the multiplexer / demultiplexer in the ninth embodiment.

FIG. 63 is a graph showing the phase distribution of the multiplexer / demultiplexer before and after the amplitude / phase adjusting plate is inserted into the multiplexer / demultiplexer in the ninth embodiment.

FIG. 64 is a graph showing transmission wavelength characteristics before and after the amplitude / phase adjusting plate is inserted into the multiplexer / demultiplexer in the ninth embodiment.

FIG. 65 is a diagram showing a manufacturing step of the amplitude / phase adjusting plate in the ninth embodiment.

FIG. 66 is an enlarged perspective view of a phase adjusting plate used in the tenth embodiment of the present invention.

[Explanation of symbols]

 11-a First input port 11-b First output port 12-a Second input port 12-b Second output port 13 Silicon substrate 14 Quartz optical waveguide 14-1 First arm waveguide 14 -2 second arm waveguide 15 thin film heater 16 groove 17 phase adjusting plate 17a polyimide film 18 adhesive 19 clad layer 20 input waveguide 21 output waveguide 22 slab waveguide 23 array waveguide 16-1 groove 16-2 groove 27 Amplitude Adjusting Plate 27-1 Phase Adjusting Plate 27-2 Amplitude Adjusting Plate 28 Adhesive 21 Absorbing Film 22 Transparent Film 23 Transparent Film 24 Metal Film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeyuki Mitachi 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Jun Abe 3-19, Nishishinjuku, Shinjuku-ku, Tokyo No. 2 Nippon Telegraph and Telephone Corporation

Claims (30)

[Claims] 1. An optical waveguide circuit having a plurality of optical waveguides on a substrate, wherein the optical waveguide circuit has a groove crossing all of the plurality of optical waveguides, and the groove adjusts optical characteristics of the optical waveguide circuit. An optical waveguide circuit with an optical property adjusting plate, comprising: 2. The optical characteristic adjusting device according to claim 1, wherein the optical characteristic of the optical waveguide is a phase of light propagating through the optical waveguide, and the optical characteristic adjusting plate is a phase adjusting plate. Optical waveguide circuit with plate. 3. The optical waveguide circuit with an optical property adjusting plate according to claim 2, wherein the phase adjusting plate is a film having a uniform refractive index and processed to have unevenness in a longitudinal direction. 4. The method according to claim 2, wherein a refractive index of the phase adjusting plate is different from a refractive index of the plurality of waveguides.
4. The optical waveguide circuit with an optical property adjusting plate according to item 1. 5. The method according to claim 3, wherein a concave portion of a film constituting the phase adjusting plate is filled with a transparent material.
4. The optical waveguide circuit with an optical property adjusting plate according to item 1. 6. The optical waveguide circuit with an optical property adjusting plate according to claim 5, wherein the refractive index of the film is different from the refractive index of a transparent material filling a concave portion of the film. 7. The optical characteristic adjusting device according to claim 1, wherein the optical characteristic of the optical waveguide is an amplitude of light propagating through the optical waveguide, and the optical characteristic adjusting plate is an amplitude adjusting plate. Optical waveguide circuit with plate. 8. The optical waveguide circuit with an optical characteristic adjusting plate according to claim 7, wherein the amplitude adjusting plate is a film having a uniform absorption coefficient and processed in a longitudinal direction. 9. The method according to claim 8, wherein the concave portion of the film constituting the amplitude adjusting plate is filled with a transparent material.
4. The optical waveguide circuit with an optical property adjusting plate according to item 1. 10. The optical waveguide circuit with an optical property adjusting plate according to claim 9, wherein the refractive index of the film is the same as the refractive index of a transparent material filling the concave portions of the film. 11. The method according to claim 11, wherein the amplitude adjusting plate includes a film having a constant thickness,
8. The optical waveguide circuit with an optical characteristic adjusting plate according to claim 7, comprising a metal film formed on the film and having a thickness different in a longitudinal direction of the film. 12. The optical characteristic adjusting device according to claim 1, wherein the optical characteristics of the optical waveguide are a phase and an amplitude of light propagating through the optical waveguide, and the optical characteristic adjusting plate is a phase and amplitude adjusting plate. Optical waveguide circuit with optical characteristic adjustment plate. 13. The optical device according to claim 1, wherein the optical characteristic of the optical waveguide is a birefringence of light propagating through the optical waveguide, and the optical characteristic adjusting plate is a birefringent adjusting plate. Optical waveguide circuit with characteristic adjustment plate. 14. The optical waveguide circuit with an optical characteristic adjusting plate according to claim 1, wherein a gap between the inner wall of the groove and the optical characteristic adjusting plate is filled with an optically transparent adhesive. 15. The optical waveguide with an optical property adjusting plate according to claim 14, wherein the optical property adjusting plate is a phase adjusting plate, and a refractive index of the phase adjusting plate is different from a refractive index of the adhesive. Wave circuit. 16. The optical characteristic adjusting device according to claim 14, wherein the optical characteristic adjusting plate is an amplitude adjusting plate, and a refractive index of the amplitude adjusting plate and a refractive index of the adhesive are the same. Optical waveguide circuit with plate. 17. The method according to claim 14, wherein the optical property adjusting plate is a birefringence adjusting plate, and one of the birefringence adjusting plates and the adhesive have the same refractive index. Optical waveguide circuit with optical characteristic adjustment plate. 18. The optical device according to claim 18, wherein at least two grooves are formed, wherein one of the optical characteristic adjusting plates is a phase adjusting plate, and the other optical characteristic adjusting plate is an amplitude adjusting plate. The optical waveguide circuit with an optical characteristic adjusting plate according to claim 1, wherein the optical waveguide circuit is an adjusting plate. 19. A groove forming step of forming a groove that crosses all of the plurality of optical waveguides in an optical waveguide circuit having a plurality of optical waveguides on a substrate, and light propagates through the plurality of optical waveguides. The optical characteristic values of the input side and the output side of each optical waveguide at the time are measured, and the adjustment amount of the optical characteristic required for each optical waveguide is determined from the error between the optical characteristic value of each input side and the optical characteristic value of the output side. An optical characteristic adjustment amount determining step of determining; an optical characteristic adjustment plate manufacturing step of manufacturing an optical characteristic adjustment plate having an optical characteristic value locally changed corresponding to each of the optical characteristic adjustment amounts; A method for manufacturing an optical waveguide circuit with an optical characteristic adjustment plate, comprising: an optical characteristic adjustment plate installation step of installing an adjustment plate. 20. The optical characteristic of the optical waveguide is a phase of light propagating through the optical waveguide, the optical characteristic adjusting plate is a phase adjusting plate, and the optical characteristic adjusting plate manufacturing step has a uniform refractive index. 20. The manufacturing method according to claim 19, further comprising a step of forming irregularities in the film having a length corresponding to a phase adjustment amount of each of the optical waveguides. 21. The optical property adjusting plate manufacturing step of manufacturing the phase adjusting plate further includes the step of forming a concave portion of the film having a uniform refractive index on which the unevenness is formed by a transparent material having a refractive index different from that of the film. 21. The method according to claim 20, further comprising a film flattening step of flattening the film by filling with a material. 22. The optical characteristic of the optical waveguide is an amplitude of light propagating through the optical waveguide, the optical characteristic adjusting plate is an amplitude adjusting plate, and the optical characteristic adjusting plate manufacturing step includes a step of forming a uniform absorption coefficient. 20. The manufacturing method according to claim 19, further comprising the step of forming in the longitudinal direction the unevenness corresponding to the amplitude adjustment amount of each optical waveguide on the film having the following. 23. An optical property adjusting plate manufacturing step for manufacturing the amplitude adjusting plate, further comprising: forming a concave portion of the film having a uniform absorption coefficient on which the unevenness is formed, having the same refractive index as the refractive index of the film. 23. The manufacturing method according to claim 22, further comprising a film flattening step of flattening the film by filling the film with a transparent material. 24. The optical characteristic of the optical waveguide is an amplitude of light propagating through the optical waveguide, the optical characteristic adjusting plate is an amplitude adjusting plate, and the optical characteristic adjusting plate manufacturing step includes the step of: 20. The method according to claim 19, further comprising a step of forming a metal film having a change in thickness in a longitudinal direction according to an amplitude adjustment amount of each of the optical waveguides. 25. The optical characteristic of the optical waveguide is a phase and an amplitude of light propagating through the optical waveguide, the optical characteristic adjusting plate is a phase and amplitude adjusting plate, and the optical characteristic adjusting plate manufacturing step includes: In a film having a similar refractive index, irregularities corresponding to the phase adjustment amount of each of the optical waveguides are formed in the longitudinal direction, and a thickness change corresponding to the amplitude adjustment amount of each of the optical waveguides is formed on the film. 20. The method according to claim 19, comprising a step of forming a metal film having a direction. 26. After the optical property adjusting plate installation step,
20. The manufacturing method according to claim 19, further comprising an adhesive filling step of filling an optically transparent adhesive into a gap between an inner wall of the groove and the optical property adjusting plate. 27. The method according to claim 26, wherein the optical property adjusting plate is a phase adjusting plate, and a refractive index of the phase adjusting plate is different from a refractive index of the adhesive. 28. The method according to claim 26, wherein the optical property adjusting plate is an amplitude adjusting plate, and the refractive index of the amplitude adjusting plate and the refractive index of the adhesive are the same. 29. At least two grooves are formed in the groove forming step, one of which is provided with a phase adjustment plate as an optical characteristic adjustment plate, and the other is provided with an amplitude adjustment as an optical characteristic adjustment plate. 20. The method according to claim 19, wherein a plate is provided. 30. Each of the optical characteristics of the plurality of optical waveguides is input to the groove of an optical waveguide circuit having a plurality of optical waveguides on a substrate and a groove crossing all of the plurality of optical waveguides. A manufacturing apparatus for an optical characteristic adjustment plate installed to adjust an error between a value on the output side and a value on the output side, wherein an error in optical characteristics between the input side and the output side of the plurality of optical waveguides of the optical waveguide circuit. And an adjustment value calculating means for calculating an optical property adjustment value based on the error value obtained by the error measuring means. An optical characteristic adjusting plate manufacturing means for obtaining the optical characteristic adjusting plate by changing the optical characteristic distribution in the longitudinal direction of the optical characteristic adjusting plate.