JPH01118806A - Composite optical waveguide type device - Google Patents

Abstract

PURPOSE:To improve the coupling efficiency by forming V grooves in the surface of a 1st surface of a transparent body closely to waveguides, reflecting light propagated in the waveguides toward the 2nd surface, and converging the reflected propagated light through a lens and arranging a packaged light receiving and emitting element at the convergence position. CONSTITUTION:There are the waveguides 2, 2a, and 2b near the 1st surface 11 of a substrate and light is propagated. When the light is sent to the waveguide 2 from the left side, it is reflected by an interference filter 6 to enter the waveguide 2a and reaches the V groove 31 and the light is reflected there, converged by the lens 41, and photodetected by the light receiving element 7. Light emitted by the light emitting element 8, on the other hand, is converged into converged light by an internal spherical lens and a lens 42 and the converged light is reflected by a V groove 32 to enter the waveguide 2b, and the light is transmitted through the interference filter 6 and enters the waveguide 2, wherein the light is transmitted to the left. Consequently, the coupling efficiency is improved.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a composite optical waveguide type comprising an optical waveguide formed near the surface of a transparent body and a light-receiving/emitting element optically coupled to the optical waveguide. Regarding devices.

[Prior Art] Conventionally, as this type of composite optical waveguide device, the one shown in FIG. 4 (for example, Japanese Patent Laid-Open No. 82-35305) has been known. In this device, a mirror 404 is provided at the end of the waveguide 401 on the substrate 402, and the light propagating through the waveguide 401 is reflected onto the upper side of the substrate.

If the light-receiving and light-emitting element 403 is placed above the mirror 404, it becomes possible to receive propagating light and to excite the light from the light-receiving and light-emitting element 403 as propagating light. Therefore, this device does not require an optical fiber to connect the optical device including the optical waveguide 401 and the light-receiving/emitting element 403, which has the advantage that the entire device can be made smaller and the number of locations for light alignment can be reduced. Ta.

[Problems to be solved by the invention]However, in the above-mentioned conventional composite optical waveguide device,
In order to increase the coupling efficiency between the light receiving and emitting element 403 and the waveguide 401, it is necessary to arrange the light receiving and emitting element 403 close to the mirror 404.

Therefore, it was difficult to seal the light receiving/emitting element 403 inside the package. Generally, in order to ensure the reliability of a light receiving/emitting device, it is essential to seal the device within a package. Therefore, in the past, the light receiving and emitting element 4
It was difficult to ensure the reliability of 03. In addition, there are other prototypes in which packaged light-receiving and light-emitting elements are directly arranged, but a method of placing a lens between the waveguide and the light-receiving and light-emitting elements has not been realized, and the coupling between the waveguide and the light-receiving and light-emitting elements has not been realized. The efficiency could not be increased. Therefore, in the conventional example, either the reliability of the light-receiving/emitting element is low, or the coupling efficiency with the light-receiving/emitting element is low due to the lack of a lens.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a V-groove in contact with or in the vicinity of the waveguide of a transparent body, and the propagating light in the waveguide is transferred to the waveguide. reflect it toward the surface opposite the surface where it was applied. A lens is installed near the surface to condense the reflected propagating light, and a packaged light-receiving/emitting element is placed at the condensing position. If necessary, an auxiliary lens for condensing light, such as a ball lens, may be included in this package. Transparent bodies that can be used in the present invention include glass, silicon, compound semiconductors, and polymers. Further, as lenses that can be used in the present invention, there are lenses formed on the surface or inside of a transparent body by various methods.

For example, a flat microlens formed by selectively ion-exchanging a portion of the surface of a glass substrate can be used. Additionally, a Fresnel lens made by forming a Fresnel zone plate using ion exchange can also be used. In addition, lenses in which a transparent liquid material is partially applied to the substrate surface by screen printing and solidified by drying or the like may also be used.

[Example] FIG. 1 is a perspective view showing the structure of a composite optical waveguide device according to an example of the present invention. Substrate 1 is for ion exchange.
Contains a small amount of Na and K as valence ions, 5102. B
It is a polished glass substrate whose main network-forming oxide is 2O3, and its thickness is, for example, 3 mm. Waveguide 2
, 2a, 2b are single mode waveguides formed near the first surface 11 of the substrate 1 by an ion exchange method. Regarding this manufacturing method, the method shown in "Characteristics of single mode waveguide by two-stage natural ion exchange method" (Proceedings No. 915), which was presented by Yukihara et al. at the 1986 IEICE National Conference, was used. Can be used.

■The grooves 31 and 32 are grooves with a V-shaped cross section formed by a pressing method on the first surface 11 side of the glass substrate 1, and have an apex angle of 4.
A 5° depth is approximately 500μ deep. As shown in an enlarged view in FIG. 2, a thin gold film 33 is deposited as a reflective film on the V-groove 31, and when light hits the V-groove 31 from the horizontal direction, the light is reflected downward. (2) A thin gold film (not shown in the figure) is also deposited on the groove 32. Lenses 41 and 42 are flat microlenses formed by an ion exchange method. lens 41
．． 42 has a diameter of 240 μm, a depth of 120 μm, and a focal length of 465 μm. The method for manufacturing this lens is described, for example, in Chapter 15 of ``New Glass and its Physical Properties'' in the new publication of Management System Research.

The groove 5 is a groove having a width of 50 .mu.-1 and a depth of 400 .mu.m, which cuts the y-shaped waveguide section consisting of the waveguides 2.2at and 2b. The interference filter 6 is a chip-shaped long wavelength pass filter (reflects light of 1.0μ or less and transmits light of 1.1μ or more) with a thickness of 45μ, and is inserted into the groove 5 to guide the light. Light beams with different wavelengths propagating through the wave paths 2* 2a* 2b are branched and multiplexed.

The light receiving element 7 is an SI avalanche photodiode package, and can receive light with a wavelength of 600 to 900 nm. The light receiving area of this diode is circular with a diameter of 200 μm, and the set pack amount from the package cap is about 0.5 μm. The light emitting element 8 is an InGaAs light emitting diode package, and has a center wavelength of 1300 nm.
It emits light with a full width at half maximum of the spectrum of 130 nm. This light emitting diode is equipped with a ball lens with a diameter of 100 .mu.m, which is not shown in the drawings, and the light from the diode is focused to some extent by this lens and given directionality before being emitted from the package.

The light receiving element 7 and the light emitting element 8 are fixed to the second surface 12 of the substrate 1 with an adhesive. In FIG. 1, they are shown separated for ease of viewing. FIG. 2 shows a waveguide 2a and a light receiving element 7.
Indicates the positional relationship between The propagating light emitted from the waveguide 2a is
After being totally reflected by the groove 31, the light advances while being diffused, is converted into a focused light by the lens 41, and is focused at an external angle of 0.51 of the substrate 1. The light receiving area of the light receiving element 7 is arranged at this position.

The positional relationship between the waveguide 2b and the light emitting element 8 is also substantially the same.

In one example, waveguides 2 and lenses 41 and 42 were fabricated on both surfaces 11° and 12 of the substrate 1 in the steps shown in FIG.

This figure is a cross-sectional view including the V-groove 31. First, the substrate 1 is prepared in step a) and placed in a high-temperature press, and a V-groove 31 is formed in a predetermined position by pressing using a precision carbide mold (step b). Next, a metal mask ff113 is deposited on the second surface 12, and an open pattern for a lens is formed at a predetermined position by photolithography and etching (step C). Thereafter, the substrate is immersed in molten salt to form a flat microlens 41 by thermionic exchange method (step d). At this time, in order to prevent ion exchange from occurring on the first surface 11, clay 15 containing kaolin etc.
Paste it there.

Next, in step e), a metal mask film 14 is deposited on the first surface 11, and an open pattern for the waveguides 2t 2av2b is formed at predetermined positions by photolithography and etching. After that, the waveguide 2* 2 at
2 Perform the first ion exchange for b (step f)
. At this time, in order to prevent ion exchange from occurring on the second surface 12, clay 15 is pasted there. Next, the mask film 14.degree. 13 is removed and a second ion exchange is performed (step g) to form the waveguide 2a.

The molten salt used in step d is a molten salt of sulfate or nitrate containing monovalent ions of TI or Ag. The molten salt used in step f is used to increase the refractive index near the opening of the mask film 14 of the substrate 1, and contains monovalent ions (i.e. Na s K + Cs, Rb, TI, Ag).
A molten salt containing at least one first ion selected from the group consisting of: In addition to sulfate or nitrate, chloride salt is added to the molten salt as necessary in order to make the ion exchange uniform and to prevent damage to the substrate 1. The molten salt used in step g is used to reduce the refractive index of the substrate 1, and is a molten salt containing at least one second ion selected from the group consisting of monovalent ions. The first ions and the second ions must have at least relatively opposite effects on the glass substrate 1 to change the refractive index.

[Function] According to the present invention, the waveguides 2t 2a, 2b are provided near the first surface 11 of the substrate 1, allowing light to propagate. When light of 0.78 μm is transmitted into the waveguide 2 from the left side, it is reflected by the interference filter 6, enters the waveguide 2a, and enters the groove 3.
1, is reflected downward, is focused by the lens 41, enters the light receiving element 7, and is received. On the other hand, the center wave and 1.30 μm light emitted from the light emitting element 8 is converted into focused light by the ball lens and lens 42 inside the light emitting element 8, is reflected by the V groove 32, enters the waveguide 2b, and passes through the interference filter 6. The light passes through the waveguide 2 and is transmitted to the left. Therefore, one embodiment functions as a composite optical waveguide module in which a light receiving/emitting element is mounted on a demultiplexing/multiplexing device for bidirectional transmission. One example is 0.78
This is the case where the light of .mu.■ is received and the light of 1.degree. 30.mu.- is emitted, but the opposite case is also possible.

Since the function of the waveguide can be determined by the waveguide pattern, waveguide parameters, etc., various devices other than the one embodiment can be manufactured.

In implementing the present invention, in order to improve the coupling between the waveguide and the light-receiving/emitting element, the thickness of the substrate, the diameter and numerical aperture of the lens, the package specifications of the light-receiving/emitting element (the depth of the light-receiving/emitting element from the package window), etc. It is desirable to optimize the In the invention, a thin gold film is vapor-deposited on the V-grooves 31 and 32 to form a high-reflection mirror, but if the V-grooves were formed at an angle that causes total reflection of all incident light, the thin gold film would be eliminated. It's okay.

[Effects of the Invention] According to the present invention, a compact composite optical waveguide device with high reliability and good coupling efficiency, which was previously impossible, can be realized. Since the lens 4 is formed on the second surface 12 of the substrate 1, even if the light emitted from the waveguide 2a and totally reflected by the V-groove 31 travels while being diffused, it is converged by the lens 41 and is reflected by the lens 41. The light is efficiently coupled to the light receiving area of the packaged light receiving element 7 arranged close to each other. Similarly, in the case of the light emitting element 8, the light from the light emitting region is focused by the lens 42 and the V groove 3
After reflection at 2, it can be guided into a waveguide.

This composite optical waveguide device does not connect the waveguide and the light-receiving/emitting element with a fiber, so it has the advantage that the number of connection points can be reduced and the device can be made smaller. In addition, since the substrate 1 includes lenses 41 and 42, the light-receiving and emitting elements can be packaged and use elements whose reliability is ensured, thereby increasing the reliability of the entire composite optical waveguide device. Can be done. Therefore, the composite optical waveguide device according to the present invention is suitable for producing bidirectional wavelength division multiplex transmission modules and the like in a small size while ensuring reliability and performance.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a composite optical waveguide device according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view showing the waveguide and lens portion used in the composite optical waveguide device, and FIG. The figure is a cross-sectional view showing the manufacturing process of a waveguide and a lens, and FIG. 4 is a cross-sectional view showing an example of a conventional composite optical waveguide device. In the figure, 1... Substrate 2s 2at 2b Old waveguide 31. 32... V groove 41, 42...
- Lens 5... Filter insertion groove 6 - Old... Interference filter 7... Light receiving element 8... Light emitting element. Figure 1 Figure 2 41 ゛1 Figure 3 Figure 4 Procedural amendment

Claims (3)

[Claims] (1) An optical waveguide formed near the first surface of the transparent body, a V-groove formed on the side of the first surface and intersecting with the optical waveguide, and light propagating in the optical waveguide is reflected by the V-groove. A composite comprising a lens formed at a position such that the lens passes through a second surface facing the first surface, and at least one packaged light-receiving element or light-emitting element disposed in close proximity to the lens. Optical waveguide device. (2) The composite optical waveguide device according to claim 1, wherein the transparent body is a glass substrate and the optical waveguide is an optical waveguide formed by an ion exchange method. (3) The composite optical waveguide device according to claim 1, wherein the transparent body is a glass substrate and the lens is a lens formed by an ion exchange method.