JPH068912U - Connection structure between optical waveguide and optical device - Google Patents

Abstract

(57) [Summary] [Object] To provide an optical waveguide-optical device connection structure capable of efficiently and accurately connecting an optical waveguide and an optical device having different optical power distributions, and easily manufacturing the optical waveguide. [Structure] A reflecting surface 5 for changing the optical axis of light propagating in the optical waveguide 2 to the substrate back surface 4 on the substrate front surface 3 of the optical waveguide substrate 1.
To form. On the other hand, on the back surface 4 of the substrate, there is formed a reflecting portion 6 for changing the optical axis of the light reflected by the reflecting surface 5 toward the front surface 3 of the substrate. Further, a light wavefront conversion unit 7 is provided on the front surface 3 of the substrate to match the light reflected by the reflection unit 6 on the back surface 4 of the substrate with the light wavefront of the optical fiber 8.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a connection structure of an optical waveguide and an optical device that can efficiently connect an optical waveguide and an optical device having different optical power distributions.

[0002]

[Prior art]

 If the optical waveguide and the optical device with different optical power distribution are directly connected, the coupling loss is large.

Therefore, conventionally, as a method for efficiently connecting an optical waveguide having a different optical power distribution and an optical device, a structure shown in FIG. 5 has been proposed. In this conventional example, a reflection surface 67 is formed so as to obliquely cut the optical waveguide 62 provided on the optical waveguide substrate 60, and a guide hole 69 for inserting the optical fiber 73 is formed on the other surface of the optical waveguide substrate 60. And a lens-shaped light wavefront conversion portion 68 is formed at the bottom of the guide hole 69.

According to this structure, the light propagating in the optical waveguide 62 is reflected by the reflecting surface 67 and reaches the optical wavefront conversion unit 68 while expanding its optical power distribution, and the optical power distribution is almost equalized. After being aligned, they are incident on the core 74 of the optical fiber 73.

[0005]

[Problems to be solved by the device]

 However, in the above-mentioned conventional example, since the surface for forming the optical waveguide 62 and the reflecting surface 67 and the surface for forming the guide hole 69 and the optical wavefront converting portion 68 are on the front and back surfaces of the optical waveguide substrate 60, However, it is difficult to accurately create the relative position between the optical waveguide 62 and the light wavefront conversion unit 68.

The present invention has been made in view of the above-mentioned points, and an object thereof is to provide an optical fiber which can efficiently and accurately connect an optical waveguide and an optical device having different optical power distributions and which can be easily manufactured. It is to provide a connection structure between a waveguide and an optical device.

[0007]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention forms a reflection surface on the surface of an optical waveguide substrate having an optical waveguide to change the optical axis of light propagating in the optical waveguide toward the back surface of the substrate, while Forming a reflection part that changes the optical axis of the light reflected by the reflection surface to the substrate surface direction, and further aligns the light reflected by the reflection part on the back surface of the substrate with the light wavefront of the optical device that connects The connection structure between the optical waveguide and the optical device was constructed by providing the light wavefront conversion part processed into such a shape.

[0008]

[Action]

 The light propagating in the optical waveguide is reflected by the reflecting surface in the thickness direction of the optical waveguide substrate, is reflected again by the reflecting portion while expanding the optical power distribution, and reaches the light wavefront converting portion. Then, the light enters the optical device in a state of being matched with the optical power distribution of another optical device connected by the optical wavefront conversion unit. Therefore, the connection loss between the two is small. Moreover, since the light wavefront conversion portion can be formed on the surface on which the optical waveguide or the reflection surface is formed, the relative positions of them can be made accurate and the production becomes easy.

[0009]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment] FIGS. 1A and 1B are views showing a first embodiment of the present invention. FIG. 1A is a side sectional view and FIG. 1B is a plan view (however, the optical fiber 8 is omitted. It is). As shown in the figure, in this embodiment, the optical waveguide 2 is formed near the substrate surface 3 of the optical waveguide substrate 1, and the light in the optical waveguide 2 is formed on the substrate surface 3 by the substrate back surface 4 of the optical waveguide substrate 1. The reflecting surface 5 is formed to change direction. Further, the back surface 4 of the substrate is provided with a reflecting portion 6 for reflecting the light reflected by the reflecting surface 5 toward the front surface 3 of the substrate again. The collimated light is matched with the light wavefront of the fiber 8.

Here, the reflecting surface 5 is formed so as to cut the optical waveguide 2 obliquely by etching the substrate surface 3 or directly cutting and polishing. If the inclination angle θ ₁ of the reflecting surface 5 does not satisfy the condition for totally reflecting the light propagating in the optical waveguide 2, a metal or the like may be deposited on the reflecting surface 5.

Next, the reflection portion 6 is formed by depositing a metal or the like on the back surface 4 of the substrate. At this time, the back surface 4 of the substrate is not processed at all.

Next, the light wavefront conversion portion 7 is processed into a spherical shape by etching the substrate surface 3 or by directly cutting and polishing.

By the way, due to the optical power distribution of the optical device (optical fiber 8 in this embodiment) to be connected, the optical path length l (l = 1) in the optical waveguide substrate 1 is obtained.₁+1₂) And the radius of curvature of the spherical surface of the light wavefront conversion unit 7. Angle θ of reflecting surface 5₁By adjusting the thickness L of the optical waveguide substrate 1, the required optical path length 1 can be obtained. The center of curvature O of the light wavefront conversion unit 7 is on the optical axis. Further, the optical axis of the light from the light wavefront conversion unit 7 of the optical waveguide substrate 1 is θ.₂Therefore, the central axis of the optical fiber 8 is n_a× sin θ₂= N_f× sin θ₃  n_a: Refractive index of the air gap 11 between the light wavefront conversion unit 7 and the optical fiber 8 (refractive index of air or adhesive) n_f: The end face 10 of the optical fiber 8 is angled θ so as to satisfy the refractive index of the core 9 of the optical fiber 8.₃You need to keep it at an angle.

With the above configuration, the light propagating in the optical waveguide 2 is reflected by the reflecting surface 5 in the thickness direction of the optical waveguide substrate 1, and is reflected again by the reflecting portion 6 while expanding the optical power distribution. Then, the light wavefront conversion unit 7 is reached. Then, the light is collimated by the optical wavefront conversion unit 7 into the optical power distribution of the optical fiber 8 and then incident on the optical fiber 8. Therefore, the connection loss between the two is small.

[Second Embodiment] FIG. 2 is a side sectional view showing a second embodiment of the present invention. In the figure, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The difference between this embodiment and the first embodiment is that the optical device (optical fiber 12 in this embodiment) is separated from the optical waveguide substrate 1. This can be configured by adjusting the radius of curvature and the optical path length of the light wavefront conversion unit 7. In the case of this embodiment, there is an advantage that the end face 21 of the optical fiber 12 need not be inclined.

[Third Embodiment] FIG. 3 is a sectional side view showing a third embodiment of the present invention. In this embodiment, in order to incline the reflecting portion 17 on the back surface 14 of the substrate of the optical waveguide substrate 20, the back surface 14 of the substrate is cut and polished to form the inclined surface 16. This makes it possible to make the optical axis of light emitted (or incident) upward from the light wavefront conversion unit 18 perpendicular to the substrate surface 13.

At this time, the inclination angle θ ₅ of the inclined surface 16 may be θ ₅ = 45 ° −θ ₄ when the inclination angle of the reflection surface 15 of the substrate surface 13 is θ ₄ . In the case of this embodiment, there is an advantage that it is not necessary to obliquely cut the end face 23 of the optical fiber 19.

Fourth Embodiment FIG. 4 is a side sectional view showing a fourth embodiment of the present invention. In this embodiment, two sets of the optical waveguide substrates 1 having the structure shown in FIG. 1 are prepared, and the optical wavefront conversion portions 7 of both sets are connected so as to face each other. In other words, instead of the optical fiber 8 shown in FIG. 1, the optical waveguide substrate 1 having the same structure is connected as an optical device.

With this configuration, the two can be connected in a state where the optical power distribution is widened, so that the loss due to the positional deviation can be reduced as compared with the case where the optical waveguides are directly connected.

By the way, in each of the above-mentioned embodiments, the light wavefront conversion portion is formed into a spherical shape, but the present invention is not limited to this, and the point is that the structure has a lens effect, such as the refractive index distribution and The optical wavefront converter may be configured by a grating.

[0023]

[Effect of device]

 As described in detail above, the connection structure between the optical waveguide and the optical device according to the present invention has the following excellent effects. Since the light wavefront conversion part can be formed on the surface on which the optical waveguide and the reflection surface are formed, their relative positions can be made accurate and the production becomes easy.

By adjusting the angle of the reflecting surface, it is possible to arbitrarily set the optical path length that the light from the optical waveguide travels in the optical waveguide substrate, and it is possible to adjust the thickness of the optical waveguide substrate without adjusting. It is possible to match the optical power distribution of the connected optical device.

Since the connection between the optical device and the optical waveguide can be performed in the state where the optical power distribution is widened, the loss due to the positional deviation can be reduced.

[Brief description of drawings]

1A and 1B are views showing a first embodiment of the present invention, wherein FIG. 1A is a side sectional view and FIG. 1B is a plan view (however, an optical fiber 8 is omitted).

FIG. 2 is a side sectional view showing a second embodiment of the present invention.

FIG. 3 is a side sectional view showing a third embodiment of the present invention.

FIG. 4 is a side sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a side sectional view showing a conventional connection structure between an optical waveguide and an optical device.

[Explanation of symbols]

 1,20 Optical Waveguide Substrate 2 Optical Waveguide 3,13 Substrate Front Surface 4,14 Substrate Backside 5,15 Reflecting Surface 6,17 Reflecting Part 7,18 Optical Wavefront Converting Part 8,12,19 Optical Fiber 9 Core

Claims (1)

[Scope of utility model registration request] 1. A reflection surface is formed on the surface of an optical waveguide substrate having an optical waveguide to change the optical axis of light propagating in the optical waveguide toward the back surface of the substrate, while the back surface of the substrate is reflected by the reflection surface. A light wave formed by forming a reflection portion that changes the optical axis of light to the surface direction of the substrate, and further processing the light reflected by the reflection portion on the back surface of the substrate into a shape that matches the light wave front of the optical device for connection. A connection structure between an optical waveguide and an optical device, characterized in that a surface conversion portion is provided.