JPH0973026A - Integrated type optical connecting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical connecting structure which is strong to disturbance and is small in size and low in cost by providing one substrate with diffraction grating type lenses and waveguide and introducing the light made incident through these diffraction grating type lenses to the optical waveguide via reflectors. SOLUTION: An input section is composed of the diffraction grating type lenses 7 existing on the rear surface of the substrate 1, the reflectors 9 formed by utilizing the diagonally etched window existing on the front surface of the substrate 1 and the optical waveguide 3. An output section 8 has the constitution similar to the constitution of the input section. Diffracted light 6 having the effect equal to the effect of the lenses is generated when the perpendicularly incident spatial parallel beams (a beam diameter sufficiently larger than the section of the waveguide) 5 from the outside are made incident on the diffraction grating type lenses 7. The diffracted light 6 propagates in the optical waveguide substrate 1. The diffracted light 6 focuses on the reflection metallic film 2 of the reflectors 9 existing at the ends of the optical waveguides 3. As a result, the diffracted light 6 reflects in the propagation direction of the waveguide and is changed in the optical path, by which the diffracted light is made into the guided light 4 propagating in the optical waveguide 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device using a planar optical waveguide and an optical connection structure for an optical fiber and spatial light. INDUSTRIAL APPLICABILITY The present invention can be used for all devices in which a device component using a planar optical waveguide is incorporated.

[0002]

2. Description of the Related Art The conventional techniques required for optical connection between a small light source (for example, a semiconductor laser) and a planar optical waveguide device in one device are mainly the following methods (1) and (2). is there. (1) Prior art 1 In prior art 1, spatial light from a small light source is once optically coupled to an optical fiber, the optical fiber is used as an optical transmission medium, and the end face thereof is directly bonded to the end face of the waveguide substrate. This is an optical connection method.

An example is shown in FIG. 4 and will be described. Light from the small light source 105 (fiber output semiconductor laser module in this example) becomes propagation light 104 through the optical fiber 103 and is directly optically connected to the end face 102 of the planar optical waveguide 101.

At this time, the end face 100 of the optical fiber 103
The end face 102 of the planar optical waveguide 101 is fixed with an optical adhesive. (2) Prior art 2 Prior art 1 is a minute lens (ball, rod lens, etc.)
This is a spatial optical connection method that combines the two.

An example of this is shown in FIG. 5 and will be described. The diverging light 307 from the small light source 305 (can type semiconductor laser in this example) is converted into parallel light 309 by the ball lens 304, propagates in the direction of the optical axis 306, and is converted into convergent light 308 by the rod lens 303. It is optically coupled to the end face 102 of the planar optical waveguide 101.

[0006]

SUMMARY OF THE INVENTION In the prior art,
Optical components such as an optical fiber, an end face of a small light source, and a micro-optical (refractive type) lens are required for optical connection with the planar optical waveguide. Therefore, there are the following problems. (1) Problem in Prior Art 1 (FIG. 4) In direct optical connection using an optical fiber, a space for accommodating the optical fiber is required in the device, so that the entire device becomes large.

In addition, a small area (φ12
Since it adheres to 5 μm), it is vulnerable to disturbance. Moreover,,
This requires a highly accurate polishing process for the connection end faces, which causes high cost. (2) Problem in Prior Art 2 (FIG. 5) In spatial optical connection using a micro optical lens group, it is difficult to align the individual lenses with respect to the optical axis of the light source and the planar optical waveguide.

In addition, each axis (x,
There is a problem that the coupling efficiency decreases due to the deviation of the relative position of (y, z, θ). Moreover, as in the case of (1), there is a problem that a highly accurate polishing process of the connection end face is required.

[0009]

[Means for Solving the Problems]

(First Means) The integrated optical connection structure according to the present invention comprises:
(A) an optical waveguide provided on the front surface of the substrate, (B) a diffraction grating lens provided on the back surface of the substrate, and (C) a reflector utilizing an oblique etching window on the front surface of the substrate,
(D) The reflector is installed at a position where light incident through the diffraction grating lens is focused, and guides light incident through the diffraction grating lens to the optical waveguide. (Second Means) The integrated optical connection structure according to the present invention comprises:
(A) an optical waveguide provided on the front surface of the substrate, (B) a diffraction grating lens provided on the back surface of the substrate, and (C) a reflector utilizing an oblique etching window on the front surface of the substrate,
(D) The reflector is installed at a position where light incident through the diffraction grating lens is focused, and reflects the light from the optical waveguide in a direction of passing through the diffraction grating lens. (Third Means) The integrated optical connection structure according to the present invention is
(A) An optical waveguide provided on the front surface of the substrate, (B) a diffraction grating type lens provided on the back surface of the substrate, (C) a reflector using an oblique etching window on the front surface of the substrate, and (D) a connector (E) the diffraction grating lens is installed on the back surface of the substrate so that the divergent light from the ferrule tip of the optical fiber focuses on the reflector, and (F) the reflector is The light that has passed through the optical fiber and has been applied to the diffraction grating lens from the tip of the ferrule is guided to the optical waveguide. (Fourth Means) The integrated optical connection structure according to the present invention is
(A) An optical waveguide provided on the front surface of the substrate, (B) a diffraction grating type lens provided on the back surface of the substrate, (C) a reflector using an oblique etching window on the front surface of the substrate, and (D) a connector (E) the diffraction grating lens is installed on the back surface of the substrate so that the divergent light from the ferrule tip of the optical fiber focuses on the reflector, and (F) the reflector is The light that has passed through the optical waveguide is reflected in a direction in which it passes through a diffraction grating type lens, and is made incident on the optical fiber. (Fifth Means) The integrated optical connection structure according to the present invention comprises:
(A) An optical waveguide provided on the front surface of the substrate, (B) a diffraction grating type lens provided on the back surface of the substrate, (C) a reflector using an oblique etching window on the front surface of the substrate, and (D) a connector (E) means for fixing the optical fiber so that the light emitted from the tip of the ferrule of the optical fiber passes through the diffraction grating lens and is focused on the reflector. It is characterized by having. (Sixth Means) The integrated optical connection structure according to the present invention is
(A) An optical waveguide provided on the front surface of the substrate, (B) a diffraction grating type lens provided on the back surface of the substrate, (C) a reflector using an oblique etching window on the front surface of the substrate, and (D) a connector An optical fiber is provided, and (E) the light passing through the optical waveguide, reflected by the reflector, and passing through the diffraction grating lens is incident on the optical fiber.
It is characterized in that means for fixing the optical fiber is provided.

The problem of the instability of the direct connection of the end faces of the optical fiber in the fixing of the adhesive material in the prior art (1) is that the diffraction grating lens and the waveguide are combined in one unit according to the integrated optical connection structure of the present invention. By integrating with the substrate, non-contact coupling between the end face of the optical fiber and the waveguide side substrate can be realized, and high-stable optical connection without an adhesive material can be realized.

Further, due to the design of the plane diffraction pattern adapted to the various types of beams propagating in the space directly from the light source, non-contact optical connection from the light source can be made to a structure which does not need to go through an optical fiber. It is also possible, and downsizing of the device can be realized.

The problem in the prior art (2), namely,
Due to the structure in which the coupling lens and the planar optical waveguide substrate are separated, the problem that relative displacement is inevitable is
According to the integrated optical connection structure of the present invention, since the waveguide and the diffraction grating type lens are constituted by a single substrate (monolithic structure), the position of the waveguide portion and the diffraction lens with high precision in photolithography Matching becomes possible.

As a result, an extremely stable optical connection with no misalignment can be realized. Further, since the connection is made in the substrate, the highly accurate end face polishing, which is a common problem of the conventional techniques (1) and (2), becomes unnecessary.

By the above means, the problems of the prior arts (1) and (2) can be solved. Then, it operates as follows. The external input light is condensed by the diffraction grating type lens on the back surface of the waveguide substrate to the oblique etching reflector at the end of the waveguide and is converted to the direction of propagating to the waveguide for optical connection. Since all of these components are integrated on a single substrate, displacement due to disturbance is eliminated. Further, polishing of the end surface is not necessary.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to FIGS.
Shown in (First Embodiment) A first embodiment of the present invention, that is, a mode of connection with external space parallel light by a diffraction grating type lens integrated type planar optical waveguide connection structure is shown in FIGS.

In the first embodiment, the input section is
It includes a diffraction grating lens 7 on the back surface of the substrate, a reflector 9 (coated with the metal film 2 as a reflection film) on the surface of the substrate by oblique etching, and a waveguide 3.

Since the output section 8 also has the same structure as the input section, input / output with external light is possible. FIG.
The operation of this optical connection structure will be described with reference to FIG.

A vertical incident space parallel light (beam diameter sufficiently larger than the waveguide cross section) 5 from the outside is a diffraction grating lens 7
When incident on, the diffracted light 6 having the same function as the lens is generated and propagates through the waveguide substrate 1.

Since the waveguide substrate 1 in this case uses a diffractive lens, the material is not particularly selected. The diffracted light 6 that performs the focusing operation is focused on the reflective metal film 2 of the reflector 9 by oblique etching at the end of the waveguide, whereby the diffracted light 6 is reflected in the waveguide propagation direction and the optical path is changed. The guided light 4 propagates through the waveguide 3.

The output side of the guided light 4 performs the opposite operation to the above, and is extracted as the output light 8 to the outside. Therefore, by adopting a diffractive lens as the coupling lens, an integral structure is formed on the front and back surfaces of the waveguide, regardless of the substrate material,
In addition, the oblique etching reflector enables optical connection to the waveguide.

Since all of them have an integrated structure using the planar technology and no conventional optical adhesive material is used, extremely stable optical connection can be realized at low cost. (Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
I will show you.

In the second embodiment, the waveguide 30
, The reflector 28 by oblique etching, and the diffraction grating lens 25 form an integral structure in the substrate 24, and the packaging 23 that holds them and the optical fiber 21 with the connection forms the whole. There is.

Next, the operation of the second embodiment (FIG. 3) will be described. The basic operation of the second embodiment is the same as that of the first embodiment. That is, the divergent light 26 from the ferrule tip 22 of the optical fiber with connector 21
However, the diffraction grating type lens 25 having a plane pattern for focusing on the reflector 28 by oblique etching is attached to the substrate 2
By producing the back surface of No. 4, the same operation as that of the first embodiment is achieved.

Since the ferrule tip 22 and the substrate 24 are spatially separated, the package 23 holds the entire optical connection structure of the present invention in order to fix the relative positional relationship.

For the package 23 and the optical connection structure, a fixing method other than an adhesive material can be adopted. For example, by fixing metallized solder to the substrate, optical connection resistant to disturbance can be realized in the optical fiber. Moreover, since the optical fiber with connector can be freely attached and detached as it is, a simple and low-cost optical connection can be realized.

[0026]

According to the present invention, a diffraction grating type lens is used as a coupling lens, and one oblique etching reflector for converting a light collection vertical to the waveguide in a horizontal direction to the waveguide. Since it is integrated on the substrate and has an integrated structure, the following effects can be obtained. (1) Disturbance (misalignment) because no adhesives are used
Optical connection to a strong waveguide is possible. (2) Since all components can be realized by a common planar technology, the cost of optical connection can be reduced. (3) A simple optical connection can be achieved by using an optical fiber with a connector.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating the operation principle of a “diffraction grating type lens-integrated planar optical waveguide and spatially parallel light optical connection structure” according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of “an optical connection structure of a diffraction grating type lens-integrated plane optical waveguide and spatial parallel light” of FIG. 1.

FIG. 3 is an enlarged cross-sectional view for explaining a configuration and an operating principle of a “optical connection structure between a diffraction grating type lens-integrated planar optical waveguide and an optical fiber” according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of “optical connection technology” of related art 1.

FIG. 5 is a configuration diagram of “optical connection technology” of related art 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical waveguide substrate, 2 ... Metal reflection film, 3 ... Optical waveguide, 4 ... Guided light, 5 ... Spatial parallel light (incident light), 6 ... Diffraction light, 7 ... Diffraction grating lens, 8 ... Spatial parallel light ( Emitted light), 9 ... Reflector, 21 ... Connector-attached optical fiber, 22 ... Ferrule tip, 23 ... Package (exterior), 24 ... Optical waveguide substrate, 25 ... Diffraction grating lens, 26 ... Divergent light (incident light), 27 ... Diffracted light, 28 ... Reflector, 29 ... Metal reflective film, 30 ... Optical waveguide, 31 ... Guided light, 100 ... Optical fiber connection end face, 101 ... Channel optical waveguide, 102 ... Channel waveguide end face, 103 ... Optical fiber, 104 Propagation light, 105 ... Optical fiber output type semiconductor laser module, 303 ... Rod lens, 304 ... Ball lens, 305 ... Can type semiconductor laser, 306 ... Optical axis, 3 7 ... divergent output light, 308 ... converging light, 309 ... parallel light.

Claims (6)

[Claims] 1. An optical waveguide (3) provided on a front surface of a substrate (1), (B) a diffraction grating lens (7) provided on a back surface of the substrate (1), and (C) the above. A reflector (9) using an oblique etching window on the surface of the substrate is provided. (D) The reflector (9) is installed at a position where the light incident through the diffraction grating lens (7) is focused, An integrated optical connection structure, which guides light (5) incident through a lattice type lens (7) to the optical waveguide (3). 2. An optical waveguide (3) provided on the front surface of a substrate (1), (B) a diffraction grating lens (7) provided on the back surface of the substrate (1), and (C) the above. A reflector (9) utilizing an oblique etching window on the surface of the substrate is provided. (D) The reflector (9) is installed at a position where the light incident through the diffraction grating lens (7) is focused, An integrated optical connection structure characterized in that light from a waveguide (3) is reflected in a direction of passing through a diffraction grating type lens (7). 3. An optical waveguide (30) provided on the front surface of a substrate (24), (B) a diffraction grating lens (25) provided on the back surface of the substrate (24), and (C) the above. A reflector (28) utilizing an oblique etching window on the substrate surface, and (D)
(E) The diffraction grating lens (25) is provided with an optical fiber (21) with a connector, and divergent light (26) from the ferrule tip (22) of the optical fiber (21) is reflected on the reflector (28). To focus on the substrate (24)
(F) The reflector (28) is installed on the back surface of
The integrated type characterized in that the light (26) which has passed through the optical fiber (21) and has been irradiated from the ferrule tip (22) to the diffraction grating type lens (25) is guided to the optical waveguide (30). Optical connection structure. 4. An optical waveguide (30) provided on the front surface of a substrate (24), (B) a diffraction grating lens (25) provided on the back surface of the substrate (24), and (C) the above. A reflector (28) utilizing an oblique etching window on the substrate surface, and (D)
(E) The diffraction grating lens (25) is provided with an optical fiber (21) with a connector, and divergent light (26) from the ferrule tip (22) of the optical fiber (21) is reflected on the reflector (28). To focus on the substrate (24)
(F) The reflector (28) is installed on the back surface of
An integrated optical connection structure, characterized in that light passing through the optical waveguide (30) is reflected in a direction of passing through a diffraction grating type lens (25) and is made incident on the optical fiber (21). 5. (A) An optical waveguide (30) provided on the front surface of a substrate (24), (B) a diffraction grating lens (25) provided on the back surface of the substrate (24), and (C) the above. A reflector (28) utilizing an oblique etching window on the substrate surface, and (D)
An optical fiber (21) with a connector is provided, and (E) the light emitted from the ferrule tip (22) of the optical fiber (21) passes through the diffraction grating lens (25),
An integrated optical connection structure comprising means (23) for fixing the optical fiber (21) so as to focus on the reflector (28). 6. (A) An optical waveguide (30) provided on the front surface of a substrate (24), (B) a diffraction grating lens (25) provided on the back surface of the substrate (24), and (C) the above. A reflector (28) utilizing an oblique etching window on the substrate surface, and (D)
An optical fiber (21) with a connector is provided, and (E) light that has passed through the optical waveguide (30), is reflected by the reflector (28), and has passed through the diffraction grating lens (25), is the optical fiber (21). ) Is provided with a means (23) for fixing the optical fiber (21) at a position where the optical fiber (21) enters.