JPH1096831A - Connecting structure of fiber array waveguide element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of waveguide elements to be acquired and to ameliorate the degradation in the yield of the waveguide elements by the waveguide abnormality of a pitch conversion section by using pitch changing waveguides which are equal at one end to the pitch of fiber arrays and are equal at the other ends to the core intervals of the fiber arrays. SOLUTION: This structure is constituted by connecting the fiber array 11, the waveguide element 10 which is integrated with only optical circuit functions, the pitch conversion waveguide element 12 which widens the waveguide pitch of the waveguide element 10 to the array intervals of the fiber array 13 and the fiber array 13. The end face 10a on the right side of the waveguide element 10 where the pitch conversion is not required is connected directly with the fiber array 11. The waveguide pitch widened on the right side of the pitch conversion part of the waveguide element 12 is made coincident with the core intervals on the connecting side of the fiber array 13. On the other hand, the right side waveguide pitch of the waveguide element 10 where only the optical circuits alone are integrated suffices with the intervals of the extent that the light propagating in the waveguides adjacent to each other do not interfere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fiber array and a waveguide element which are connected to each other at intervals of a waveguide pitch of the waveguide element so as not to interfere with propagating light. The present invention relates to a connection structure for connecting a fiber array and a waveguide element using a pitch conversion waveguide whose waveguide pitch has been widened.

[0002]

2. Description of the Related Art In a conventional connection structure between a fiber array and a waveguide element, a pitch converter for expanding a waveguide pitch of an optical circuit to a core interval of the fiber array and an optical circuit are integrated in the waveguide element on the same substrate. There is a structure in which a waveguide element formed in this way is connected to a fiber array.

FIG. 3 shows an example of a connection structure between the above-described conventional fiber array and a waveguide element. FIG. 3A is a plan view showing a connection structure between the fiber array and the waveguide element.
3B is a sectional view taken along the line aa ′ in FIG. 3A, and FIG. 3C is a sectional view taken along the line bb ′ in FIG. These figures are examples in which a waveguide element 30 having an optical circuit of a 1 × 16 splitter is connected to a fiber array 31 having an optical fiber 31a mounted on both sides thereof and a fiber array 32 having an optical fiber 32a mounted thereon. is there.
That is, the waveguide element 30 is constructed by integrating an optical circuit section 30a and a pitch conversion section 30b, one end of which has a waveguide pitch p1 and the other end of which is converted to the core interval d1 of the fiber array 32, on the same substrate. I have.

As described above, as the number of waveguides in the fiber array 32 connecting the right optical fiber 32a increases, the waveguide element width w1 and the waveguide element width w1 are increased to increase the waveguide pitch p1 to the core interval d1 of the fiber array 32. The length L1 needs to be long. Therefore, as shown in FIG. 4, when fabricating these waveguide elements 30 from the wafer 33, 1
The number of waveguide elements 30 that can be manufactured from one wafer decreases, and the manufacturing cost per waveguide element 30 increases.

[0005] From the above, conventionally, FIG.
As shown in FIG. 1, a proposal has been made for the waveguide element 40 to have a trapezoidal structure. That is, fiber arrays 43 and 44 are connected to both sides of the waveguide element 40.
As shown in FIG. 6, a trapezoidal waveguide element 4 is
An attempt has been made to increase the number of obtained waveguide elements 40 by alternately arranging 0s. However, even if the waveguide elements 40 are arranged in a trapezoidal manner in this manner, the number of obtained waveguide elements 40 from one wafer 41 is slightly less than twice. It cannot be expected to significantly reduce the manufacturing cost. Also, the pitch converter 3
If there is an abnormality in the waveguide element 0b, even if the optical characteristics of the optical circuit section 30a are obtained, the total of the waveguide elements 30 and 40 becomes defective, and the yield is reduced.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made to solve the above-mentioned disadvantages of the prior art, and to obtain a waveguide element in which only an optical circuit portion is integrated from a wafer. It is an object of the present invention to provide a novel connection structure of a pitch conversion waveguide element capable of increasing the number and improving a reduction in the yield of the waveguide element due to a waveguide abnormality in the pitch conversion section.

According to the present invention, a waveguide element which satisfies the function of an optical circuit is separated from a waveguide element which satisfies the function of the optical circuit, and a pitch conversion part which extends the waveguide to the core interval of the fiber array for connecting the optical circuit with the fiber. This leads to an increase in the number of waveguide elements obtained by integrating only optical circuits from the wafer, and a reduction in the yield of waveguide elements due to an abnormal waveguide in the pitch converter, thereby reducing overall costs. It is to reduce greatly.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a connection between a waveguide element having an integrated optical circuit and a fiber array.
This is a connection structure of a fiber array waveguide element that connects a fiber array and a waveguide element by using a pitch conversion waveguide having one end equal to the pitch of the fiber array and the other end having a waveguide pitch equal to the core interval of the fiber array. . Further, the waveguide pitch of the waveguide element in which the optical circuit is integrated is a connection structure of the fiber array waveguide element in which an interval at which light propagating in the adjacent waveguides does not interfere is set, and the waveguide pitch of the optical circuit is: This is a connection structure of a fiber array waveguide element that is narrower than the core interval of the fiber array.The connection surface between the waveguide element with integrated optical circuit and the pitch conversion waveguide and the connection surface between the optical fiber array and the pitch conversion waveguide are reflected. This is a connection structure of a fiber array waveguide element that is polished obliquely to 8 degrees or more to obtain an attenuation amount. Further, the pitch conversion waveguide is a connection structure of a fiber array waveguide element formed using a quartz substrate or a silicon substrate.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B are plan views each showing a connection structure of a fiber array waveguide element according to an embodiment. That is, the connection structure of the fiber array waveguide element is such that the waveguide pitch of the waveguide element 10 for connecting the fiber array 11, the waveguide element 10 in which only the optical circuit function is integrated, and the fiber array 13 is set to the fiber array 1
The fiber array 13 is connected to a pitch conversion waveguide element 12 extended to both sides to an array spacing of 3.
The end face 10a on the left side of the waveguide element 10 that does not require pitch conversion connects the fiber array 11 directly as in the related art. FIG. 1B shows an example in which a pitch conversion waveguide element 14 expanded to only one side as a pitch conversion waveguide element is similarly connected.

Hereinafter, the dimensions of the waveguide element of the embodiment will be described in comparison with a conventional waveguide element structure. FIG. 2A is a plan view showing a conventional waveguide element structure. That is, the waveguide element 20 has the optical circuit unit 20a and the pitch conversion unit 20b formed on the same substrate. FIG. 2 (b) shows a waveguide element 21 formed by integrating only the optical circuit function of the present invention on a quartz or silicon substrate, and FIG. 2 (c) expands the pitch of the waveguide of the present invention to a certain interval. This is a rectangular waveguide element 22 having a pitch converter formed on a quartz or silicon substrate, and FIG. 2D shows a trapezoidal waveguide element 25 of a trapezoidal pitch converter according to the present invention.

Hereinafter, the dimensions of the waveguide element will be compared with those of a 1 × 16 splitter having a relative refractive index difference Δ = 0.3%. Pitch converter 20b of conventional waveguide element 20
Must be matched with the core spacing 0.25 mm on the side to which the fiber array (not shown) is connected, so that the width d2 of the total core spacing is d2 = 0.25.times. 15 = 3.75 mm.

On the other hand, the waveguide pitch d1 'on the right side of the waveguide element 21 in which only the optical circuit of the present invention is integrated is sufficient if the distance is such that light propagating in adjacent waveguides does not interfere. When the refractive index difference Δ = 0.3%, d1 '
= 0.03 mm. The width d1 of the total core interval is d1 = 0.03.times.15 = 0.45 mm.

As a result, the width of the waveguide element 21 of the present invention is about 1/8 of that of the conventional waveguide element 20. Therefore, the number of waveguide elements 21 obtained from the wafer is about eight times (d2 / d1 = 8.3) even if only the width direction is considered, and the manufacturing cost per waveguide element can be greatly improved. it can. Further, the length L2 of the waveguide element 22 of the pitch converter is about 1/3 of the length L1 of the conventional waveguide element 20, so that the number of the waveguide elements 22 obtained from the wafer is tripled. . Further, as shown in FIG.
The waveguide element 2 from the wafer is obtained by making the shape of 5 a trapezoid.
5, the number of acquisitions further increases. Since the waveguide elements 22 and 25 of the pitch conversion unit are manufactured separately from the waveguide element 21 of the optical circuit unit, a decrease in the yield of the waveguide element 21 due to the abnormality of the waveguide element 22 is eliminated.

These waveguide elements 21, 22 or 2
5 are manufactured separately and then the contact surfaces are connected to form a fiber array waveguide element. At this time, in order to minimize the return loss of each contact surface, each contact surface is cut at an angle of 8 degrees or more, and these are polished and connected.

[0015]

As described above, according to the connection structure of the fiber array waveguide element of the present invention, the waveguide element connects the waveguide portion satisfying the function of the optical circuit, the waveguide of the optical circuit, and the optical fiber. In order to increase the number of waveguide elements that integrate only optical circuits from the wafer, it is possible to increase the number of waveguide elements that are integrated by separating the pitch conversion part that extends the waveguide to the core spacing of the fiber array. The yield can be improved due to the waveguide abnormality in the portion, and the cost can be significantly reduced.

[Brief description of the drawings]

FIGS. 1A and 1B are plan views each showing a connection structure of a fiber array waveguide element according to one embodiment;

FIG. 2A is a plan view showing a conventional waveguide device structure,
(B) is a plan view showing a waveguide element having only an optical circuit function of the present invention integrated therein, (c) is a plan view showing an example of a waveguide element having only a pitch conversion section of the present invention, and (d). Is a plan view showing another example of the waveguide element having only the pitch conversion portion of the present invention,

3 (a) is a plan view showing a conventional connection structure between a fiber array and a waveguide element, and FIG. 3 (b) is aa ′ of FIG. 3 (a).
FIG. 3C is a cross-sectional view taken along the line bb ′ of FIG.

FIG. 4 is a layout view of a waveguide element manufactured from a wafer.

FIG. 5 is a plan view showing a connection structure between a fiber array and a waveguide element showing another conventional example,

FIG. 6 is a layout view of a process of manufacturing the waveguide element of FIG. 5 from a wafer.

[Explanation of symbols]

 10, 31, 32, 40 Waveguide element 10a End face 11, 13 Fiber array 12, 14 Pitch conversion waveguide 30a Optical circuit unit 30b Pitch conversion unit 33, 41 Wafer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshikazu Kamoshida 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Pref.

Claims (5)

[Claims] In a connection between a waveguide element in which an optical circuit is integrated and a fiber array, a pitch conversion waveguide having a waveguide pitch at one end equal to the pitch of the fiber array and the other end equal to the core interval of the fiber array is used. A connection structure for a fiber array waveguide element, wherein the fiber array and the waveguide element are connected. 2. The fiber array waveguide device according to claim 1, wherein the waveguide pitch of the waveguide device in which the optical circuit is integrated is set so that the light propagating through the adjacent waveguides does not interfere with each other. Connection structure. 3. The connection structure for a fiber array waveguide device according to claim 1, wherein the waveguide pitch of the optical circuit is smaller than the core interval of the fiber array. 4. The connection surface between the waveguide element integrated with the optical circuit and the pitch conversion waveguide and the connection surface between the optical fiber array and the pitch conversion waveguide are obliquely polished to 8 degrees or more to obtain the return loss. 2. The connection structure for a fiber array waveguide device according to claim 1, wherein: 5. The pitch conversion waveguide is formed using a quartz substrate or a silicon substrate.
The connection structure of the fiber array waveguide element described in the above.