JP2003066391A - Multiwavelength optical modulating device and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small multiwavelength optical modulating device with high performance. SOLUTION: This multiwavelength optical modulating device is provided with an array waveguide area 302-2 having a total reflection surface 303-2, an AWG for demultiplexing having a slab waveguide area 301, an array waveguide area 302-1 having a total reflection surface 303-1, an AWG for multiplexing having a slab waveguide area 301, a plurality of optical modulation elements 309-1 to 309-N, and via waveguide areas 308-1 and 308-2 for connecting the AWG for demultiplexing, the AWG for multiplexing and the plurality of optical modulation elements, and configures the slab waveguide area of the AWG for demultiplexing and the slab waveguide area of the AWG for multiplexing so as to be a common slab waveguide area 301.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-wavelength optical modulator and a manufacturing method thereof, and more particularly to a multi-wavelength optical modulator used in optical information communication and the like and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, optical communication has been used in many information communication networks due to its large capacity and ultra-high speed. In such an optical communication network, optical semiconductor components are widely used for light emitting elements, light receiving elements, etc., and research and development thereof are actively conducted.

Research and development of optical semiconductor parts is carried out by using a semiconductor laser (LD; laser diode) or a photodiode (PD; pho).
Not to mention individual parts such as to diode), LD and P
D, semiconductor optical amplifier (SOA; semiconductor optical)
amplifier), electro-absorption optical modulator (EA; electro abs)
(orption modulator) is also vigorously done to monolithically integrate optical devices that can be made of semiconductors on a semiconductor substrate.

In order to realize a large capacity of optical communication, a wavelength division multiplexing (WDM) transmission system for propagating a large number of optical signals having different wavelengths in a fiber is used. In this method, a large number of optical signals can be transmitted by one fiber, so that a large capacity can be realized at low cost.

However, in order to prevent signals from interfering with each other, it is necessary to strictly set and manage the wavelength of each signal light. In such a case, it is important to construct a cheap network by using a multi-wavelength light source that can generate and manage a continuous wave (CW; continuous wave) light at one place in a concentrated manner. It is considered to be used. In such a multi-wavelength light source, a plurality of CW lights are generally output from one port.

Therefore, in the case of individually modulating the CW light of each wavelength, the configuration of the multi-wavelength optical modulator as shown in FIG. 1 is required. First, the CW light 102 output from one port of the multi-wavelength light source 101 is converted into the CW light 1 by the demultiplexing optical circuit 103.
04-1 (wavelength λ1) to CW light 104-N (wavelength λN)
Demultiplex each wavelength. Next, the individual light modulation elements 105-
The CW light 102 is modulated for each wavelength from 1 to 105-N. Finally, the combined light circuit 106 combines the modulated lights of the respective wavelengths to obtain a modulated light 107.

As an element structure for realizing this, an arrayed waveguide (AWG) is used as a multiplexing / demultiplexing optical circuit.
The configuration using an electro-absorption optical modulator (EA) as an ide grating) and an optical modulator is considered to be the simplest configuration.

FIGS. 2A and 2B are diagrams showing a configuration example of a conventional multi-wavelength optical modulator. FIG. 2A is a diagram showing a structure in which the EA is inserted in parallel between the demultiplexing AWG and the multiplexing AWG. FIG. 2B shows the same A
FIG. 6 is a diagram showing a configuration in which WG performs demultiplexing and multiplexing, and EA is arranged in parallel between them.

The multi-wavelength optical modulator shown in FIG. 2A is an AWG
201-1, AWG 201-2, slab waveguide 202-
1, slab waveguide 202-2, EA203a-1 to 20
3a-N, entrance port 205-1, exit port 206-
Has 1 etc.

As shown in FIG. 2A, a normal AWG 201
In -1, the incident light 204-1 is distributed to each arrayed waveguide 207 through the slab waveguide 202-1 and a phase difference is given by the optical path length difference of the arrayed waveguide 207, and then the slab waveguide 202-2. To the waveguide 208.

At this time, since the given phase difference differs depending on the wavelength, the light of each wavelength forms an image at a different position. Therefore, it is possible to perform demultiplexing for each wavelength by setting a desired phase difference and the position of the emission port. In addition, it is possible to combine light by propagating light in the opposite direction.

In this conventional example, the function can be realized with a simple structure without a crossed waveguide or the like. However, in order to obtain a high wavelength resolution, the AWG needs to lengthen the slab waveguide region and the arrayed waveguide in principle, and occupies a large element area. The increase in the element area directly leads to a decrease in the yield per wafer, which makes it difficult to reduce the cost.

Further, as the wavelength spacing of the signal light becomes narrower, higher wavelength accuracy of the multiplexing / demultiplexing characteristic is required.
Since the positions are apart from each other, the deviation of the wavelength characteristics of the multiplexing side and the demultiplexing side AWG due to the manufacturing error becomes large. this is,
This is because there is always an in-plane distribution in a manufacturing process such as photolithography or an etching process, and the amount thereof generally increases as the positions of the two increase.

As a solution to the above problem, as shown in FIG. 2B, there is a configuration in which the same AWG is used for multiplexing and demultiplexing, and EA is arranged in parallel between them. The multi-wavelength optical modulation device of FIG. 2B includes AWG201-3, EA203b-1 to 203b-.
N, an entrance port 205-2, an exit port 206-2, and the like.

In this conventional example, since the AWGs 201-3 are the same, the element area is halved, and the deviation of the combined / demultiplexed wavelength due to the manufacturing error is eliminated. However, AWG201
The light 204-2 output from the EA 203b-1 to 203b-N is multiplexed by using the same AWG 201-3, and output from the 1-port emission port 206-2 like the light 204-3. When trying to output, AWG
From the circularity of 201-3, it is necessary to return to the original order,
In principle, the cross waveguide 209 is essential.

In such a portion of the cross waveguide 209,
Crosstalk between waveguides and scattering losses occur. In order to prevent the deterioration of crosstalk, it is necessary to set the intersection angle to a certain value or more. This means that bent waveguides are required to intersect the waveguides. If the crossing angle is 90 degrees (right angle) so that the crosstalk deterioration is minimized, at least one rectangular region having a bending radius of the waveguide is required at one crossing portion as shown in FIG. 2B. Since the number of intersecting portions increases with the number of wavelengths, the area of the intersecting waveguide region increases, crosstalk deteriorates, and scattering loss also increases. Further, since the waveguide itself becomes long due to the routing, the insertion loss deteriorates.

[0017]

As described above, in the multi-wavelength optical modulator, the element area increases, the wavelength deviation of the multiplexing / demultiplexing characteristics due to the manufacturing error, and the crosstalk and the insertion loss due to the crossed waveguides deteriorate. However, there is a problem to be solved in the prior art that it cannot be solved at the same time.

The present invention has been made in view of the above problems, and an object thereof is to provide a small-sized and high-performance multi-wavelength optical modulator and a manufacturing method thereof.

[0019]

In order to achieve such an object, the invention according to claim 1 provides a total reflection surface (303).
-2) having an arrayed waveguide region (302-2) and a slab waveguide region (301), and an arrayed waveguide region (30) having a total reflection surface (303-1).
2-1) and an AWG for multiplexing having a slab waveguide region (301), and a plurality of optical modulators (309-1 to 309-).
N), the demultiplexing AWG, the multiplexing AWG, and the via waveguide region (308-
1, 308-2), and the slab waveguide region of the demultiplexing AWG and the slab waveguide region of the multiplexing AWG are common slab waveguide regions (301). .

According to a second aspect of the present invention, in the multi-wavelength optical modulator according to the first aspect, the via waveguide region comprises:
It is characterized in that it does not have a crossing portion of the via waveguide.

The invention described in claim 3 is the invention according to claim 1 or 2.
The multi-wavelength optical modulation device according to claim 1, wherein the demultiplexing AWG
Of the array waveguide region of the multiplexing AWG and the array waveguide region of the multiplexing AWG have the same total reflection surface in each array waveguide region, and the array waveguide region of the demultiplexing AWG and the multiplexing waveguide Each of the arrayed waveguide regions of the AWG is characterized by including a linear waveguide (311) perpendicular to the total reflection surface of each arrayed waveguide region.

The invention according to claim 4 is the AWG for demultiplexing.
And the AWG for multiplexing and the light modulation element regions (309-1 to 309-3).
09-N), the demultiplexing AWG and the combining AWG
And an optical waveguide region (308
-1, 308-2) is a method of manufacturing a multi-wavelength light modulator formed by monolithic integration on a semiconductor substrate, and the first step of forming the light modulator element region (FIG. 4A). (B)) and the optical waveguide device region formed in the first step as a reference, the arrayed waveguide region (302-2) and the common slab waveguide region (30).
1) the demultiplexing AWG, an arrayed waveguide region (302-1) and the common slab waveguide region (301)
A second step (FIGS. 4 (c) to (e)) of forming the combining AWG having:
The demultiplexing AWG formed in the second step
On the respective end faces of the arrayed waveguide region and the arrayed waveguide region of the multiplexing AWG.
3-2) forming a third step (FIG. 4 (f)).

According to a fifth aspect of the present invention, in the method of manufacturing a multi-wavelength optical modulator according to the fourth aspect, the passing waveguide region having no crossing portion of the passing waveguide is formed by the second step. It is formed.

The invention according to claim 6 is the invention according to claim 4 or 5.
In the method for manufacturing a multi-wavelength optical modulator described in (3), when the total reflection surface is formed by the third step, the array waveguide region of the demultiplexing AWG and the array waveguide of the multiplexing AWG. In each of the waveguide regions, a linear waveguide (311) is formed perpendicular to the total reflection surface of each array waveguide region, and the linear waveguide (311) is formed in the array waveguide region of the demultiplexing AWG and the array waveguide region of the multiplexing AWG. Each of the total reflection surfaces is formed so as to be the same surface.

The reference numerals in the drawings of the constituent portions of the embodiment corresponding to the constituent elements in the claims are shown in parentheses. However, the constituent elements described in the claims are not limited to the constituent portions of the embodiment of the above () section.

[0026]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) FIG. 3 is a diagram showing the structure of a multi-wavelength optical modulator of this embodiment. As shown in FIG. 3, the elements of the multi-wavelength optical modulator are the demultiplexing AWG 1 including the common slab waveguide 301, the arrayed waveguide 302-2, the total reflection surface 303-2, and the output waveguide 304. , A common slab waveguide 301, an arrayed waveguide 302-1, a total reflection surface 303-1, and an AWG 2 for multiplexing which is composed of an input waveguide 305, and the slab waveguide 30.
The areas of No. 1 are arranged so as to overlap each other.

An input port 306 and an output port 307 for external light are arranged in the input / output regions of the AWG 1 and AWG 2, respectively. The plurality of via waveguides 308-1 and 308-2, which are output from the input / output region of each AWG, are connected to the EAs 309-1 to 309-N corresponding to the respective waveguides, respectively.

The outline will be described below along the propagation of the incident light 310. Incident light 310 having a plurality of wavelengths is AW
It advances from the incident port 306 of G1 to the slab waveguide 301 and the arrayed waveguide 302-2. Total reflection surface 303-2
The more reflected light travels backward and propagates through the arrayed waveguide 302-2 and the slab waveguide 301.

In the AWG having this structure, the total reflection surfaces 303-1 and 303-2 are formed in the center of the conventional AWG and the light is folded back, so that the element area can be halved while maintaining the demultiplexing function. Cost reduction is possible. At this time, the input port 306 and the output port after the demultiplexing are set such that the optical path length difference and the port position in the arrayed waveguide 302-2 do not overlap. A specific setting method will be described below.

Considering N wavelengths with equal incident wavelength intervals, with a plurality of wavelengths as λ1 to λN from the shorter side (here, N is 3).
More than an odd number). When white light is input from the center port, the wavelength output from the center port becomes the center wavelength λc, and the AWG slab waveguide 301 and the waveguide connected to the slab waveguide 301 are connected so that they can be combined / demultiplexed at the wavelength interval of the incident light 310. The waveguide position and the optical path length difference of the arrayed waveguide 302-2 are set. Also, the central wavelength of the incident wavelength group and λc are combined to obtain c =
(N + 1) / 2. The above can be designed by the same method as the conventional AWG.

First, the incident port 306 of the AWG 1 is set to the port which is c above the center port. In this way, due to the circularity of the AWG, the light demultiplexed from λN to λ1 is output to each port from the lower side to the lower side of the central port of the AWG1. Set these ports as output ports. As a result, the incident port 306
The function can be satisfied without the output port crossing.

Next, the demultiplexed CW light is input from the output port to the EAs 309-1 to 309-N corresponding to the respective waveguides through the transit waveguide 308-1. Each CW light is modulated by EA309-1 to 309-N, and then AW
It is guided to the via waveguide 308-2 toward G2.

It is necessary to design the optical path length difference between the input port and the output port 307, the slab waveguide 301, and the arrayed waveguide 302-2 so that the transit waveguide 308-2 does not intersect in the AWG2. Specifically, it is as follows.

The input to the AWG 2 is set so that the light demultiplexed from λN to λ1 is input from one lower side of the central port to the lower side, and these are set as input ports. Similar to AWG1, in AWG2, when white light is input from the center port, the wavelength output from the center port becomes the center wavelength λc, and the AWG slab waveguide is used so that the wavelengths of incident light 310 can be combined / demultiplexed. Thirty
1 and the optical path length difference between the arrayed waveguide 302-1 are set. By doing this, due to the circulation of the AWG, the AWG2
Since the modulated light that has been multiplexed is output from the port above the center port by c, the output port 3
07.

The AWG1 and AWG2 have a structure in which the regions of the common slab waveguide 301 are overlapped. This allows
It is possible to reduce the element area without design restrictions such as crossing other waveguides. Further slab waveguide 3
01 becomes the same position, and array waveguides 302 of both AWGs
Since the regions of -1 and 302-2 can be brought close to the regions of the input waveguide 305 and the output waveguide 304, the manufacturing error largely dependent on the position can be reduced.

At this time, the crosstalk of the light propagating through the AWG1 and the AWG2 becomes a problem, but the crosstalk can be sufficiently reduced by making the crossing angle of both AWGs sufficiently large, for example, by making them orthogonal. The increase in device area due to this is slight, and it hardly depends on the number of ports.

By the way, the total reflection surfaces 303-of both AWGs
Although it is possible to fabricate 1, 303-2 completely independently, by utilizing the advantage of this structure that the regions of the arrayed waveguides 302-1 and 302-2 can be close to each other by sharing the slab waveguide 301. The manufacturing error on the total reflection surfaces 303-1 and 303-2 can be reduced. Specifically, it is as follows.

For example, when the present structure is made of an InP type semiconductor, the total reflection surfaces 303-1 and 303-2 are usually made by cleavage. Since the cleavage position accuracy is about several μm, an error occurs in the arrayed waveguide length and a wavelength shift occurs in the multiplexing / demultiplexing characteristics. Further, even if the cleavage position is the same, the cleavage direction of the semiconductor substrate and the element direction determined by the accuracy of photolithography have an angular shift. If the distance between the AWGs is large as in the conventional example, the cleavage position shift due to the angle shift increases, and the wavelength shift occurs in the multiplexing / demultiplexing characteristics.

In this structure, the AWG total reflection surface 303-
Since 1 and 303-2 are perfectly matched and are brought close to each other, it is possible to suppress the wavelength shift of the multiplexing / demultiplexing characteristics as described above. Further, by disposing the linear waveguide 311 perpendicular to the cleavage plane around the cleavage position, even if the cleavage position is displaced, the optical path length difference of the arrayed waveguide can be prevented from changing, so that the multiplexing / demultiplexing characteristic can be obtained. The wavelength shift can be suppressed to a small value.

As described above, in the present configuration, the element area can be significantly reduced by eliminating the crossed waveguide region and forming the folded structure of the AWG, and the slab waveguide 301 can be further reduced by sharing the region. In addition, the slab waveguide 301
Since the AWG manufacturing positions can be brought close to each other by sharing, there is an advantage that the wavelength shift of the multiplexing / demultiplexing characteristics due to the manufacturing error is small. Further, since there is no crossed waveguide at all, high crosstalk and low insertion loss can be expected even if the number of ports is increased.

As a result, the yield per wafer is high, the cost can be reduced, the multiplexing and demultiplexing characteristics are excellent, and even if the number of ports is increased, high crosstalk and low insertion loss can be simultaneously satisfied. A modulator can be realized.

(Embodiment 2) FIGS. 4A to 4F are views showing a method of manufacturing the multi-wavelength optical modulator of this embodiment. FIGS. 4A to 4F show first to sixth stages of manufacturing the multi-wavelength optical modulator, respectively. In addition, all the crystal growth steps in this embodiment are MOVPE (metalorganic v
apor phase epitaxial) method.

In FIG. 4A, first, n-type (n-)
The GaInAsP EA active layer 4 is formed on the InP substrate 401.
02, p-type (p-) InP cladding layer 403 and p-I
The nGaAs cap layer 404 is grown on the entire surface.

In FIG. 4B, plasma CVD (ch
SiO ₂ film 405 by the emical vapor deposition) method
-1 is formed, photolithography and CF4 _/ H 2 -R
S other than EA area by IE (reactive ion etching)
The iO ₂ film is removed. Using this SiO ₂ film as a selective mask, the p-InGaAs cap layer 404, the p-InP clad layer 403, and GaInA are wet-etched.
The sPEA active layer 402 is removed.

In FIG. 4C, the SiO ₂ film 405-
Using 1 as a selective mask, the GaInAsP AWG waveguide layer 406 and the i-InP clad layer 407 are grown by butt joint selective growth. SiO ₂ by wet etching
The membrane 405-1 is removed.

[0047] In FIG. 4 (d), the plasma CVD method to form an SiO ₂ film 405-2, by photolithography and _CF4 / H 2 -RIE, EA region and AWG region, the SiO ₂ film except over the waveguide Remove. This Si
Using the O ₂ film 405-2 as a mask, the semiconductor layer is etched by Br ₂ -RIE for 3 to ₄ μm to form a high-mesa waveguide. SiO ₂ film 4 by wet etching
Remove 05-2.

In FIG. 4E, a polyimide region 408 is formed beside the high mesa waveguide in the EA region by photolithography and O ₂ -RIE. An AuZnNi contact electrode and a Ti / Pt / Au pad electrode are formed on the EA region and the polyimide region (reference numeral 409 in the figure) by photolithography and EB (electron beam) deposition, respectively.

In FIG. 4 (f), after polishing the back surface,
The AuGeNi electrode 410 is formed by EB evaporation. After cleavage, TiO ₂ / SiO ₂ was formed on the end face of the input / output waveguide.
AR (anti reflection) coatings 411-1 and 4
11-2, and TiO ₂ / SiO ₂ HR on the total reflection end face
(High reflection) coatings 412-1 and 412
-2 is formed.

Although the manufacturing method on the InP substrate is described here, the same structure may be used on the GaAs substrate. Further, the waveguide may be formed of different materials such as a glass waveguide. Further, the light modulation element is a semiconductor EA or SOA.
Alternatively, it may be constituted by a thermo-optic effect switch of a glass waveguide or the like.

[0051]

As described above, according to the present invention, a multi-wavelength optical modulator includes a demultiplexing AWG having an arrayed waveguide region having a total reflection surface and a slab waveguide region, and a total reflection surface. A multiplexing AWG having an arrayed waveguide region and a slab waveguide region, a plurality of optical modulation elements, and a via waveguide connecting the demultiplexing AWG, the multiplexing AWG, and the plurality of optical modulation elements. And a slab waveguide region of the demultiplexing AWG and a slab waveguide region of the multiplexing AWG are common slab waveguide regions.

Therefore, it is possible to realize a multi-wavelength optical modulator that has a high yield per wafer and can be manufactured at low cost.

Further, according to the present invention, the above-mentioned via-waveguide region of the above-mentioned multi-wavelength optical modulator does not have a crossing portion of the via-waveguide.

Therefore, in addition to the above effects, it is possible to realize a multi-wavelength optical modulator capable of high crosstalk and low insertion loss even if the number of ports is increased.

Further, according to the present invention, the above-mentioned multi-wavelength optical modulator includes a total reflection surface of each arrayed waveguide region in the arrayed waveguide region of the demultiplexing AWG and the arrayed waveguide region of the multiplexing AWG. Are on the same plane, and each of the arrayed waveguide region of the demultiplexing AWG and the arrayed waveguide region of the multiplexing AWG includes a linear waveguide perpendicular to the total reflection surface of each arrayed waveguide region. .

Therefore, it is possible to realize a multi-wavelength optical modulator having excellent multiplexing / demultiplexing characteristics.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of individual modulation of CW light of each wavelength in a multi-wavelength optical modulator.

FIG. 2 is a diagram showing a configuration example of a conventional multi-wavelength optical modulator,
(A) shows that between the demultiplexing AWG and the multiplexing AWG, E
FIG. 3A is a diagram showing a structure in which A is inserted in parallel, and FIG. 6B is a diagram showing a configuration in which the same AWG performs multiplexing and demultiplexing, and EA is arranged in parallel between them.

FIG. 3 is a diagram showing a configuration of a multi-wavelength optical modulator according to an embodiment of the present invention.

FIG. 4 is a diagram showing a method of manufacturing a multi-wavelength optical modulator according to an embodiment of the present invention, in which (a) is a first stage of manufacturing, (b) is a second stage of manufacturing, and (c) is a manufacturing stage. It is a figure which shows the 3rd stage, (d) the 4th stage of manufacture, (e) the 5th stage of manufacture, (f) the 6th stage of manufacture.

[Explanation of symbols]

101 multi-wavelength light source 102 CW light 103 demultiplexing light circuit 104-1 to 104-N CW light 105-1 to 105-N light modulation element 106 multiplexing light circuit 107 modulated light 201-1, 201-2, 201-3 AWG 202 -1,202-2 Slab waveguides 203a-1 to 203a-N, 203b-1 to 203b
-NEA 204-1, 204-2 Light 205-1, 205-2 Incident port 206-1, 206-2 Outgoing port 207 Array waveguide 208 Waveguide 209 Cross waveguide 301 Common slab waveguide 302-1, 302 -2 arrayed waveguides 303-1 and 303-2 total reflection surface 304 output waveguide 305 input waveguide 306 input port 307 output ports 308-1 and 308-2 through-pass waveguides 309-1 to 309-N EA 310 incident light 311 Linear waveguide 401 n-InP substrate 402 GaInAsP EA active layer 403 p-InP clad layer 404 p-InGaAs cap layer 405-1, 405-2 SiO ₂ film 406 GaInAsP AWG waveguide layer 407 i-InP clad layer 408 Polyimide Area 409 EA area and polyimide area 410 AuGe i electrode 411-1,411-2 TiO ₂ / _{SiO 2} AR coating 412-1,412-2 TiO ₂ / _{SiO 2} HR coating

Claims (6)

[Claims] 1. A demultiplexing AWG having an arrayed waveguide region having a total reflection surface and a slab waveguide region, and a combining AWG having an arrayed waveguide region having a total reflection surface and a slab waveguide region. A plurality of optical modulation elements, the demultiplexing AWG and the multiplexing AWG, and a via waveguide region that connects the plurality of optical modulation elements, the slab waveguide region of the demultiplexing AWG and the AW for multiplexing
A multi-wavelength optical modulator, wherein the G slab waveguide region is a common slab waveguide region. 2. The multi-wavelength optical modulator according to claim 1, wherein the via waveguide region does not have an intersection of the via waveguides. 3. The multi-wavelength optical modulator according to claim 1, wherein all array waveguide regions of the array waveguide region of the demultiplexing AWG and the array waveguide region of the multiplexing AWG are included. The reflection surface is the same surface, and the demultiplexing A
A multi-wavelength optical modulator, wherein each of the array waveguide region of the WG and the array waveguide region of the AWG for multiplexing includes a linear waveguide perpendicular to a total reflection surface of each array waveguide region. 4. A demultiplexing AWG, a demultiplexing AWG, a light modulation element region, the demultiplexing AWG and the demultiplexing AWG.
A method of manufacturing a multi-wavelength optical modulator in which a via waveguide region connecting the optical modulator region and the optical modulator region is formed on a semiconductor substrate by monolithic integration, the first step of forming the optical modulator region. And the demultiplexing AWG having an arrayed waveguide region and a common slab waveguide region based on the light modulation element region formed in the first step, an arrayed waveguide region and the common slab waveguide, And a multiplexing AW having a region
G, a second step of forming the via waveguide region, and the demultiplexing AWG formed in the second step
And a third step of forming a total reflection surface at each end face of the array waveguide region of the multiplexing AWG and the array waveguide region of the multiplexing AWG. Method. 5. The method for manufacturing a multi-wavelength optical modulator according to claim 4, wherein the via waveguide region having no intersection of the via waveguides is formed by the second step. Method for manufacturing multi-wavelength light modulator. 6. The method for manufacturing a multi-wavelength optical modulator according to claim 4, wherein the third step comprises:
When the total reflection surface is formed, each of the arrayed waveguide region of the demultiplexing AWG and the arrayed waveguide region of the multiplexing AWG is linearly guided perpendicularly to the total reflection surface of each arrayed waveguide region. A multi-wavelength characterized in that a waveguide is formed, and total reflection surfaces of the arrayed waveguide region of the demultiplexing AWG and the arrayed waveguide region of the multiplexing AWG are formed in the same plane. Method of manufacturing light modulator.