JPS61185991A - Optical coupling device - Google Patents

Abstract

PURPOSE:To enable fixture with high junction efficiency by a method wherein a resin introduced groove, which can flow excessive resin, is formed to a bottom part of a concave section formed on a compound semiconductor substrate. CONSTITUTION:An activator region 3, which is extended to [110] face direction, is formed with regard to [100] face of an InP substrate and a window 7 is made after masking an SiO2 film e.g. on the whole face, then an (a) section of the window 7 becomes a V-groove guide 4 after etching thereof and (b) section becomes a resin introduced groove 5. When H3PO4/HCl system etching is performed for the substrate crystal, the V-groove appears finely on the V- groove guide, then the groove 5 is formed to the groove introduced section due to crystal orientation dependability of etching. In the groove depth, the resin introduced groove 5 side is trimmed to be about several mum deeper than the V groove 4 side. When the optical fiber is fixed on the V-groove guide, optical output, which the optical fiber accepts from laser active region, is almost the same value as that before introducing resin. Thereby, loss before and after fixing of the optical fiber is made zero, therefore high efficient junction can be performed in that respect and it becomes a stable optical coupling device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical coupling device that facilitates and accurately aligns an optical waveguide or an optical electrical circuit with an optical fiber.

Conventional technology In coupling optical waveguides and opto-electrical devices to optical fibers,
Semiconductor devices have already been proposed in which a guide mechanism for positioning is formed by selective etching on a compound semiconductor substrate on which an optical waveguide or an opto-electrical circuit is formed, allowing positioning by simply placing an optical fiber.

A method for manufacturing such a semiconductor device is, for example, as shown in FIG.
Utilizing the crystal orientation dependence of 2Po4 etching, a V-groove guide 4 for positioning the optical fiber 2 is formed in the extension of the active region (optoelectric circuit) 3 of the striped laser (for example, (Sho es7-141890).

A semiconductor device having a V-groove guide 4 formed by the above method can be positioned simply by placing an optical fiber on the V-groove guide. Conventionally, as shown in FIG. 7, as a method for fixing the optical fiber 2 onto the V-groove formed on the substrate 1, the optical fiber 2 is installed in the V-groove guide 4.
A method of applying epoxy resin 1o from above was used.

Problems to be Solved by the Invention Conventional methods have been used to remove concave portions (V in FIGS. 6 and 7) on the substrate.
When the optical fiber is fixed in the groove), the resin is applied from above the optical fiber, so the lower part of the optical fiber, that is, V
The resin wraps around the bottom of the groove, causing the optical fiber to lift up or shift laterally, causing the optical fiber to shift from its original position. The problem arises that it gets very bad.

Means for Solving the Problems In order to solve the above problems, in the present invention, a resin introduction groove into which excess resin can flow is formed at the bottom of a recess formed on a compound semiconductor substrate.

Effect: By using the above technical means, the excess resin applied to fix the optical fiber on the recess easily flows into the resin introduction groove, causing the optical fiber to float up or cause lateral displacement. The optical waveguide or optoelectric circuit can be fixed with high accuracy without any displacement on the recess already provided in position with the optical waveguide or the optoelectric circuit. Therefore, it becomes possible to immobilize with almost the same binding efficiency as before introduction of the resin.

Embodiment FIGS. 1 and 2 show an optical coupling device between a semiconductor and an optical fiber 2, which has a resin introduction groove 5 on the bottom side surface of a V-groove guide 4 in an embodiment of the present invention. That is, I
! A V-groove guide 4 is formed on the IP substrate 1, and the optical fiber 2 is fixed to this guide 4, and a resin introduction groove 5 for pouring resin into the substrate 1 at the bottom of the guide 4 is provided.
is provided. To explain the manufacturing of this device, as shown in FIGS. 3 and 4, an active region 3 extending in the [11o] direction is formed on the [10o] surface of an InP substrate using a known technique. Next, after masking the entire surface with a Sio2 film or the like, a window 7 is opened above the active region.

After etching, the (a) part of this window 7 becomes the ① groove guide 4 and the 0)) part becomes the resin introduction groove 5. Here, opening the window on the mask must be done with accurate alignment. When this substrate crystal is subjected to H3PO4/HCp-based etching, a V-groove 4 appears neatly in the V-groove guide part as shown in FIG.
Due to the crystal orientation dependence of O4/HCl1 etching, a groove 6 having a bottom as shown in FIG. 6(C) is formed. When using the above etching solution, if etching is stopped immediately after the tip of the groove (2) of the (1) groove guide portion is formed into a clean V-groove, the depths of the (2) groove guide resin introduction grooves become equal. However, in the resin introduction groove 5 of this embodiment,
In order to prevent the optical fiber on the groove guide 4 from floating up or shifting its position, it is necessary that the excess resin flow into the resin introduction groove and keep it in a low state, so the depth of the groove is set to V.
The effect will be further improved if the resin introduction groove 5 is made deeper by several micrometers than the depth of the groove guide 4.

As previously mentioned in FIG. 5, the InP substrate 1 exhibits completely different etching characteristics depending on the direction due to the H3PO4/HCp etching crystal orientation dependence, but by utilizing the above characteristics, It becomes possible to form the resin introduction groove 6 several micrometers deep. That is, in (1) groove etching, there is a characteristic that even if etching is continued at a point where the bottom of the groove becomes V-shaped, the groove will not become any deeper. However, even if etching is performed in the opposite direction, that is, in the direction of the resin introduction groove, with the above solution at the same time as (2) etching the groove guide portion, the groove will not become V-shaped due to the etching characteristics. Therefore, if etching is continued, the depth will become infinitely deep. In other words, the depth of the resin introduction groove 5 is several μm smaller than the depth of the V-groove guide 4.
It is appropriate to stop etching when the depth is m.

In this example, the proportion of the etching solution is H2PO4
:If the HCR fraction increases by more than 1 = 2, the axial end surface will not become [110]. This part also serves as one reflection surface of the laser [11o
] Since it is an absolute condition that the etching solution has a flat surface, special care must be taken regarding the proportion of the etching solution.

In this embodiment, the angle between the V-groove of the groove guide portion and the horizontal plane is determined to be approximately 36°. The width of this V-groove guide determines the depth of the groove, and therefore the position of the core is fixed according to the thickness of the optical fiber, so it depends on the outer diameter of the optical fiber used and the laser active area. Uniquely determined by the depth from the surface. ■The length of the groove guide is only used for fiber alignment, so it only needs to be long enough for that purpose. Next, the depth of the resin introduction groove is several μm deeper than the ■ groove, as shown in Figure 1.
It is sufficient that the width is about 180 μm and the length is about 1001a.

In a semiconductor device manufactured by the above method and having a resin introduction groove, when an optical fiber is fixed on the above groove guide, the light output received by the optical fiber from the laser active region is different from that before the resin introduction. The values were almost the same. If the same thing was done using the conventional method where the resin introduction groove was not formed on the bottom side of the V-groove guide on the InP substrate, a shift would occur due to the influence of the resin, and the light output after fixing would be compared to before the introduction of the resin. The value was several inches smaller. The resin used here is an epoxy room temperature curing resin.

In the above embodiments, the active region 3 is an electric circuit, such as a semiconductor laser or a photodiode. It goes without saying that the opto-electric circuit may be an optical waveguide.

Effects of the Invention As described above, according to the present invention, by utilizing the etching crystal orientation dependence of a semiconductor substrate and forming an alignment recess and a resin introduction groove on the bottom side surface of the recess on the substrate, it is possible to form a recess in the recess. The resin applied to fix the installed optical fiber flows into the resin introduction groove, so the positioned optical fiber is not lifted up due to the influence of the resin and misaligned, and the recessed position is fixed. Fixed. Therefore, there is no loss before and after fixing the optical fiber, and in that sense it is possible to perform coupling with high coupling efficiency.
A stable optical coupling device was obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the optical coupling device of the present invention;
2(A) and 2(B) are a side view and a front view of the ■groove guide portion for positioning the device of the same embodiment, and FIG. 3. Figure 4 is a diagram for explaining the method for manufacturing the V-groove guide and resin introduction groove of the same device, and Figures 6 (A) and (B) are InP.
FIG. 6(C) is a perspective view and a cross-sectional view of the V-groove guide when the substrate is etched with H3PO4/HCR solution. (D) is a perspective view and a sectional view of the resin introduction groove when etched, FIG. 6 is a perspective view of a conventional optical coupling device, and FIG.
A) and (B) are a side view and a front view of the positioning V-groove guide portion of the device. 1...InP substrate, 2...Optical fiber, 3...Active region VC (photoelectric circuit), 4...
... V groove guide, 5 ... Resin introduction groove, 6 ...
····Epoxy resin. Name of agent: Patent attorney Ken Nakao and 1 other person 1st
Artwork 9P@Rebellion 2nd figure (8) (B)ryL
/'Kiyoul Figure 3 Figure 4 Figure 5 (A) (C) (B) (v) Be = Kankan

Claims (3)

[Claims] (1) An optical coupling characterized by having a recess formed on a semiconductor substrate, an optical fiber fixed to the recess, and a resin introduction groove into which resin formed on the semiconductor substrate at the bottom of the recess is poured. Device. (2) The optical coupling device according to claim 1, characterized in that an optical waveguide or a photoelectric circuit is formed on a semiconductor substrate. (3) The optical coupling device according to claim 2, wherein the opto-electric circuit comprises a semiconductor laser or a photodiode.