JPS6375711A - Optical coupling structure - Google Patents

Abstract

PURPOSE:To easily and stably couple an optical element with an optical fiber with good reproducibility by providing the optical element with a support part which supports the optical fiber mechanically. CONSTITUTION:Laser light is emitted from the light emission part 12 of the end surface of the laser resonator of the optical element 11 and coupled with the optical fiber 13. This optical fiber 13 is supported by the support part 14 and fixed with metal 15 with a low melting point. This support part 14 is a V groove of 200mum in length and worked at a time in the manufacture process of the optical element 11. Thus, the support part 14 is worked with high accuracy, so the coupling operation for the optical fiber 13 is extremely easy, there is no need for fine adjustments, and the reproducibility is excellent. Further, the position of the optical fiber 13 is determined unequivocally, so the stability is also improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technique for attaching a source fiber to an optical device, and particularly relates to an optical coupling structure suitable for easily obtaining high optical coupling efficiency with good reproducibility. .

[Conventional technology]

In a conventional optical coupling structure consisting of an optical element and an optical fiber, for example, as described in Japanese Patent Application Laid-Open No. 56-94316,
The optical fiber was inserted into an opening in a low melting point metal body having an oversized opening extending through it, and was fixed by solidifying the low melting point metal body after the bath melted and flowed out.

[Problems that the invention attempts to solve]

In the conventional example described above, since the opening of the metal body has excessive dimensions, the position of the original fiber must be manipulated by a fine adjustment device so that the optical fiber is optically coupled to the element. Further, the optical fiber is embedded and fixed in the low melting point metal body.

Conventionally, fine adjustment work has been required in order to combine the optical seven-eye putty into an optical element as described above.

The above-mentioned work is difficult and requires a great deal of effort and time. Besides, during fine adjustment work and melting the low melting point metal body,
! Since the optical coupling efficiency varies depending on the conditions when solidifying and fixing, there was a problem with its reproducibility. Furthermore, since the optical fibers are embedded and fixed in the low melting point metal body, the positions of the five optical fibers are easily affected by deformation of the low melting point metal body, which poses a problem regarding the stability of optical coupling efficiency.

An object of the present invention is to provide an optical coupling structure for easily achieving optical coupling between one element and an optical fiber with good reproducibility and stability.

[Means for solving problems]

The above object is achieved by providing the optical element with a portion that mechanically supports the optical 7-eyeper.

[Effect]

The optical fiber and mechanical support part provided in the optical device are created by the same process as the optical device, so
Can be processed with high precision. Therefore, when mounting the optical fiber on the support portion, there is no need to make fine adjustments to the position of the optical fiber, which improves the efficiency of the mounting work and improves the reproducibility of the single beam combination efficiency.

Furthermore, since the position of the optical fiber is mechanically and uniquely determined, stability is also improved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the manufacturing process of an optical device according to the A1 embodiment of the present invention, and FIG. 2 is a diagram showing the first embodiment of the present invention. FIG. 3 is a diagram showing the second embodiment, and FIG. 4 is a diagram showing the effect of improving the stability of the above embodiment.

“First, let me explain from Figure 2.

FIG. 2 is a diagram showing a first embodiment of the optical coupling structure according to the present invention. In the figure, the optical element 11 is made of InGaAsP.
/InP-based buried heterostructure semiconductor. Wavelength 1, 3
The emitted light in μm is emitted from the light emitting part 12 at the end face of the laser co-shaker and is optically coupled to the optical fiber 13. The optical fiber 3 is made by etching a single mode fiber, which normally has a diameter of 125 .mu.m, with an ammonium fluoride mixture to a diameter of 30 .mu.m in order to be mounted on the optical element 11. The tip of the optical 7 eyeball 13 is processed into a spherical shape to provide a lens effect in order to increase the optical coupling efficiency with the light emitted from the 1 light emitting section 12. The optical fiber 13 is fixed to an optical fiber support portion 14 provided on the optical element 11 with a low melting point metal 15. The optical fiber support portion 14 has a length of 20 mm.
A V-shaped groove of 0 μm is machined. Note that the position and depth of the V-groove are sufficiently controlled so that optimal optical coupling is achieved when the optical fiber 13 is ia-connected. In this example, Pb-40wt% 8n:,yda was used as the low melting point metal 15.

Certain portions of the optical fiber 13 and optical fiber support portion 14 are provided with gold metallization 16, 17 to enhance adhesion to the low melting point metal 15.

Next, the manufacturing process of the optical device 11 of the first embodiment will be explained with reference to FIG. The optical fiber support portion 14 is also processed all at once in this process. FIG. 41 shows a flowchart of the manufacturing process and a perspective view of a portion of the wafer in each process. The following will be described in accordance with the order of the processes shown in FIGS. 1(A) to 1(F).

Embedded heterogeneous purchasing formation process The process of forming an embedded heterostructure.

Literature “Journal Op Ogtechal Communication Vol. 1 No. 10 1980 (J.

Qpt, (:'otrmun,, 1. 10.198
0) Proceed in the same manner as described in J. Mesa etching during the process is described in one document, “IEEE J, Quantum Electron.
Nies), Volume QE-18, No. 10, No. 1704
~1711 pages.

The etching was carried out using the same bromine-methanol mixed solution as the etching solution described in 1982.

Figure 1 AK? and r1MInP substrate 1 (plane index (10
0)) The upper InGaA8P active layer 2 includes a p-type InP cladding layer 3, a p-type IflP block layer 4, and an n-type InP layer 5.
, and extends in the (011) direction in a striped manner. 7 Its thickness is 0.2 μm2 width is 1.4
A mask 6 is formed which is necessary for etching to form a 1° V-groove mask having a depth d of 4.1 μm from the top surface of the wafer. After depositing an 8jCh film by CVD, patterning is performed by photolithography. vI# The mask for the part to be completely formed is in the form of a stripe with a width of W (
It is removed in the direction (011,>). At this time, 1 width W
The mask pattern is sufficiently aligned so that the center line of the portion and the center line of the stripe of the InGaAsP active layer 2 coincide with each other.

Note that since the angle θ of vn is the angle between crystal planes and is constant, the depth d' of vn is determined by the interval W between the masks 60. To achieve optimal optical coupling.

The radius r of the optical fiber and the depth d and V of the buried active layer 2
From the angle θ of the groove, W is determined by the following formula.

In this example, r = 15.0 μm, d =
4.1 am.

Since θ=70.5°, W=42.5ttm.

V-groove formation process When anisotropic etching is performed using a hydrochloric acid-phosphoric acid mixture (rich in hydrochloric acid), a crystal plane (111) appears, as shown in Figure 1C.
vn7 (direction (011,>2) is formed as shown below. This vn7 is the optical fiber support portion 14 of the first embodiment.

It should be noted that it is possible to perform both mesa etching and V-groove formation etching in the buried heterostructure formation process, as shown in the above-mentioned document IEEE J, Quantum.
glectronics.

Vol, QE 18. 41 0. pp,
1704-1711°1982.

The depth d' of the V-groove in this example is 30.1t from equation (1).
It is tm.

Step of Forming Mask for Laser End Face As shown in the first diagram, a mask 8 necessary for etching to form the laser end face is formed. 810* by sputtering
A film is deposited and patterned by photolithography. Mask 8 is also formed on the side surface of V#.

V-za end face formation step Next, reactive ion etching using chlorine-based gas plasma is performed to form the (Ill ((011> direction)
s9 to form a V-the end face 10.

Regarding reactive ion etching, please refer to the literature “Electronics Lette”.
rs) Vol. 19, No. 6, p. 213, 1983. In at the end face 10
The GaA3F active layer 2 is the light emitting layer 12 in FIG.

Electrode formation process Electrode formation is performed in the same manner as in the case of a normal semiconductor laser.

An Au/Cr electrode is formed on the p-type InP cladding layer 3 shown in FIG.
3 Form an n-electrode. Further, the metallized portion 17 of the optical element 11 is also formed at the same time as the ALI/Crtffl is formed. (The above illustrations are omitted) Opening process: Place the wafer between the bones along the dashed dotted line in Figure 1E.

It is divided into individual chips, that is, optical elements 11, as shown in FIG. One of the two laser end faces per optical element is formed by opening the valve.

By batch processing of Queha shown in the above process, the first
Optical element 11 of the embodiment? can be created. Optical element 1
1 is provided with an optical fiber support portion 14 in the form of a V-shaped groove.

According to the process of this embodiment as described above, the processing accuracy of the optical fiber support portion 14 can be controlled to 1 μm or less with good reproducibility. Further, the position of the optical fiber 13 in this embodiment is mechanically and uniquely determined by the V-shaped groove of the optical fiber support part 4. Therefore, there is no need to finely adjust the position of the optical fiber 13, and high optical coupling efficiency can be easily obtained simply by mounting the optical fiber 23 on the optical fiber support portion 14.

In order to investigate the reproducibility of the optical coupling efficiency of the 5g1 example, 50 optical coupling structures of the first embodiment and the conventional structure were fabricated as prototypes, and the number distribution with respect to the optical coupling efficiency was measured. As a result, it was confirmed that the first example had the same or better reproducibility than the conventional example.

Is Figure 3 the invention? @2 used in optical communication module
Example? FIG. First, optical element 11 having the optical coupling structure of the present invention? It was fixed on Matante 18. After the optical fiber 13i4 introduced into the package 20 from the outside is fixed at the fixing part 9 of the mount 18, the optical element 1 is further fixed.
It was fixed to the optical fiber support part 14 on 1. Fixed part 19
and the diameter of the optical fiber between support portion 14? 125
The lateral stress exerted on the support portion 14 by increasing K1flll from μm to 30 μm? It was reduced to about 1/100.

FIG. 4 is a diagram showing the effect of improving stability in the J2 embodiment. 4 degree 100C between 20 optical communication modules having the optical coupling structure according to the present invention and 20 conventional modules
These are the results of temporal changes in optical coupling efficiency in the lower part. The horizontal axis of the figure is time, and the vertical axis is the change in optical coupling efficiency? show. In conventional systems, the optical fiber support and the optical element were made of different materials, which caused thermal stress due to the difference in thermal expansion coefficients, causing creep deformation in the low melting point metal body of the optical fiber support. . In comparison, in the second embodiment, there is no difference in the coefficient of thermal expansion between the optical element 13 and the optical fiber support portion 14, and the position of the optical fiber 13 is determined by the V-shaped groove of the optical fiber support portion 14. Therefore, no deformation occurs. From FIG. 4, it was confirmed that this example had the effect of improving the stability of optical coupling efficiency.

〔Effect of the invention〕

According to the present invention, it is possible to easily obtain high optical coupling efficiency with good reproducibility and stability, thereby simplifying the mounting work and improving economic efficiency.

Note that since the optical coupling structure according to the present invention has a simple microstructure, Toyoko conversion is possible, and it goes without saying that the present invention can be implemented in, for example, an optical conduit selection circuit arranged in an array with optical elements. Also, when using optical fibers for interconnection between optical elements, fiber resonator lasers, fiber type lasers, fiber sensors, etc. Which optical fibers have special functions? It goes without saying that even in the case of implementation, the present invention can be implemented and obtained.

[Brief explanation of the drawing]

FIG. 1 is a process explanatory diagram showing the manufacturing process of an optical device according to a first embodiment of the present invention, and FIG. 2 is a process explanatory diagram showing a manufacturing process of an optical device according to a first embodiment of the present invention. The perspective view of the optical coupling structure shown in FIG. 3 is a second embodiment of the present invention. FIG. 4 is a cross-sectional view of the optical coupling structure shown, and a graph showing the effect of improving the stability of the above embodiment. 11... Optical element, 13... Optical fiber, 14...
Optical 7 A VJ1 Fig. 7 V groove mask depth 1 Fig./ρ L-Sir flame surface f Z Fig./l Photoelectric te/Z Luminous sound P 73 Y fiber/4 Opposite optical 7 fiber Sound P 15 A, a4 Tue, to Tun U

Claims (1)

[Claims] 1. In an optical coupling structure consisting of an optical element and an optical fiber,
An optical coupling structure characterized in that the optical element is provided with a portion that mechanically supports the optical fiber. 2. The optical coupling structure according to claim 1, wherein the portion supporting the optical fiber is processed all at once in the manufacturing process of the optical element. 3. The optical coupling structure according to claim 1, wherein a V-shaped groove is formed in the portion supporting the optical fiber. 4. In an optical coupling structure consisting of an optical element and an optical fiber,
2. The optical coupling structure according to claim 1, wherein the diameter of the tip of the optical fiber is reduced.