JPH04175706A - Connecting structure of wave guide type optical element and optical fiber - Google Patents

Abstract

PURPOSE:To perform assembling and alignment easily and precisely, improve reliability, and remove the effect of thermal expansion by fixing a wave guide type optical ele ment, a connecting member and an optical fiber to a fixing tool, respectively, and positioning and aligning the light wave guide path of the wave guide type optical element, the core of the connecting member and the core of the optical fiber. CONSTITUTION:An optical element fixing section 31 fixing a wave guide type optical element 2, a connecting member fixing section 32 fixing a connecting member 3 provided in front of light wave guide paths 12, 13, and a fiber fixing section 33 fixing an optical fiber 4 provided in front of it are provided on a fixing tool 5. The wave guide type optical element 2, connecting member 3 and optical fiber 4 are fixed to the fixing tool 5 respectively, and the positioning and alignment of the light wave guide path of the wave guide type optical element 2, the core of the connecting member 3 and the core of the optical fiber 4 are performed. The wave guide type optical element 2 and the optical fiber 4 are connected. The positioning and alignment of the light wave guide path and the core of the optical fiber 4 can be performed easily and precisely, reliability is improved, the effect of thermal expansion is removed, and the temperature characteristic can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to the connection of optical fibers and waveguide optical devices such as optical switches and optical branching/coupling waveguides used in the fields of optical communications and optical information processing. The present invention relates to a coupling structure, and particularly relates to a structure in which an optical waveguide of a waveguide type optical element and an optical fiber core are coupled using a fixture and via a coupling member having a larger diameter than the optical fibers to be coupled.

[Prior Art] Conventionally, as a method for coupling a waveguide type optical element and an optical fiber, for example, the end face direct coupling (butt-coupling) method is well known.

In this method, for example, the end face of the optical waveguide of a waveguide type optical element formed on a substrate and the end face of the core of a single mode optical fiber are coupled by adjusting the positions of both with high precision. This method is suitable when the wave path and optical fiber fields are relatively coincident.

[Problem to be solved by the invention] By the way, in the conventional end face direct coupling method, a high efficiency of about -2 dB can be obtained by matching the distribution of the incident wave and the waveguide moat and changing the parameters to A. , Unwritten shot: 1-tinog, etc., have various features such as being able to reduce reflection loss and having a simple structure, but it is difficult to adjust the end faces with high precision. Therefore, work efficiency was poor, and since the effects of thermal expansion on both sides were not equal, temperature characteristics tended to increase (L).

In order to improve this temperature characteristic, the outer peripheral surface of the above-mentioned optical fiber is coated with a coating material such as ceramic or crystalline material, and a single optical fiber is used. Although it is possible to reduce the temperature characteristics when using , it has the disadvantage that the influence of thermal expansion cannot be removed.

This invention was made in view of the above circumstances, and is a waveguide type optical element that can be assembled and adjusted easily and with high precision, can improve reliability, and can eliminate the effects of thermal expansion. and to provide a coupling structure for optical fibers.

4. Means for Solving the Problems 1-1 To solve the problems described above, the present invention employs various coupling structures of waveguide type optical elements and light-Ty2. . In other words, it is a structure in which the optical waveguide of the waveguide type optical element and the core of the optical fiber are coupled via a coupling member having a diameter larger than that of the bonding furnace delta optical fiber (using a fixture), The fixing device includes an optical element fixing part for fixing the waveguide type first element, a coupling member fixing part 3 provided in the front part of the optical waveguide of the optical element fixing part and fixing the coupling member, and the coupling member fixing part 3 for fixing the coupling member. a fiber fixing part provided in the front part of the member fixing part and fixing the optical fiber; By aligning and aligning the optical waveguide of the waveguide type optical element, the core of the coupling member, and the core of the optical fiber, the waveguide type optical element and the optical core inode are coupled. It is a feature.

[For use] The coupling structure of the waveguide type optical device of the present invention and the optical fiber l (
j1 It is easier to align and align the optical waveguide of the waveguide type optical element and the core of the condyle 1 with high accuracy, and the influence of the swelling is eliminated by using the joining member.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a coupling structure l of a waveguide type optical device and an optical fiber according to the present invention. In the figure, reference numeral 2 denotes a waveguide type optical element, 3, 3 . is a connecting member, 4.4. is an optical fiber, and 5 is a fixture.

The waveguide type optical element 2 is made of, for example, lithium niobate (Li
An optical waveguide 12 is formed on a substrate lIL that is N bo s) or l = N.
It is a 2×2 optical switch with a length J of 45 mm and a width of 4 mm. The waveguide type optical element 2 is made of, for example, a wood M'tz substrate made of glass epoxy resin, carphone fiber epoxy resin, polyimide resin, polyester resin, or a ceramic substrate made of alumina, zirconia, ittria, carnoy, etc. The first waveguide device is created by bombarding a chipped optical switch, optical branching/coupling waveguide, or other waveguide type optical device on a substrate with a small expansion coefficient.
Ru.

The coupling member 3 is a large-diameter optical fiber made of the same material as the optical fiber 4 to be measured later, with a length of 9 mm, an outer diameter of 10 μm, and an outer diameter of I mm. Does one end 3a of this coupling member 3 have a conical shape? , : is formed, and the tip portion is reduced in outer diameter to 125 μm, and the other end portion 3b is polished into a substantially hemispherical shape with R=35 μm to prevent reflection.

The other end portion 3b is not limited to being polished into a substantially hemispherical shape, and may be, for example, a flat surface polished without reflection.

The outer peripheral surface 3C of this coupling member 3 is coated with a metal material.

For example, the optical fiber 4 has a mode field diameter of 9 μm,
It is a single mote quartz optical fiber with a core diameter of 10 μm and an outer diameter of 125 μm. And the first fiber 4.4. - Each optical waveguide 12 (1
, 3), respectively, so that their axes coincide with each other.

As shown in FIG. 2, one end 3a of the coupling member 3 and one end 4a of the optical fiber 4 are coaxially coupled by ordinary fusion splicing, and the other end of the coupling member 3 3b is coupled to the end surface 12b (13b), which is likely the end surface 12a (13g) of the optical waveguide +2 (+3) of the waveguide type optical element 2. Note that the method for connecting the coupling member 3 and the optical fiber 4 is not limited to the above-mentioned fusion splicing, and various connection methods are possible, and for example, adhesive splicing or the like is preferably used.

The fixture 5 is composed of an upper lid 21 and a fixing part main body 22, and by fitting the upper M21 and the fixing part main body 22 to each other, the waveguide type optical element 2, the coupling member 3゜3, . . . Fiber 4.4. - each is fixed, and the optical waveguide 12.13 of the waveguide type optical element 2 and the coupling member 3.3. ..., optical fiber 4.4. ... The alignment with each core and the sincerity can be performed easily and with high precision. This fixture 5
includes an optical element fixing part 31, a coupling member fixing part 32, 32.
..., fiber fixing part 33.33. is formed.

The optical element fixing part 31 is a long notch with a rectangular cross section formed in the center of each of the upper cover 21' and the fixing part main body 22 in order to fix the waveguide type optical element 2. be. A plurality of coupling member fixing parts 32.32 are formed in front of the optical waveguides 12.13 of the waveguide type optical element 2 located at both ends of the optical element fixing part 31 in the longitudinal direction.

The coupling member fixing fKI 32 is for fixing the coupling member 3 so that the axes of the optical waveguides 12 and 13 and the coupling member 3 coincide with each other. This is a long groove with a semicircular cross section formed on both end faces so that the longitudinal direction of each of the grooves matches the longitudinal direction of the fixture 5. This connecting member fixing part 3
2 has a fixed radius of the coupling member 3.

The fiber fixing part 33 is provided at the front part of the coupling member fixing part 32 of the upper cover 21 and the fixing part body 22, respectively, for fixing the optical fiber 3 so that the coupling member 3 and the optical fiber 4 match in detail. It is a coaxially formed elongated groove with a semicircular cross section. A radius of the optical fiber 3 is fixed to this fiber fixing portion 33 .

Next, a method for coupling the optical waveguides i2, 13 of the waveguide type optical element 2 and the core of the optical fiber 4 via the coupling member 3 using the fixture 5 will be described.

First, the lower half of the waveguide type optical element 2 is accommodated in the optical element fixing part 31 of the fixing part main body 22, the radius of the coupling member 3 is accommodated in the coupling member fixing KI32, and the fiber fixing part 33 is first accommodated. It accommodates the radius of fiber 4.

Next, the other end 3b of the coupling member 3 is brought into contact with the end surface 12a (13a) of the optical waveguide +2 (+3) of the waveguide type optical element 2, and the other end 3b of the coupling member 3 and the waveguide type optical element 2 are connected. Optical waveguide 12 (
13). Similarly, the other end 3b of the coupling member 3
comes into contact with the end surface 12b (13b) of the optical waveguide +2 (+3) to couple the other end 3b of the coupling member 3 and the optical waveguide 12 (13) of the waveguide type optical element 2.

Next, one end 3a of the coupling member 3 and one end 4a of the tip fiber 4 are coaxially coupled by ordinary fusion splicing.

Next, with the optical waveguide 12C13), the coupling member 3, and the optical fiber 4 coaxially coupled, the lower half of the waveguide type optical element 2 is attached to the optical element fixing part 31 using an adhesive such as epoxy resin. , the radius of the connecting member 3 to the connecting part (O fixing part 32),
Each radius of the optical fiber 4 is adhered and fixed to the fiber fixing portion 33.

Here, the outer circumferential surface of the end of the optical fiber 4 to be coupled is coated with a metal such as aluminum or gold in advance.
By fixing with solder instead of an adhesive such as epoxy resin, a bonded structure with better temperature characteristics can be obtained.

Finally, the top 1121 is fitted to the fixing part main body 22 to integrate the top lid 21 and the fixing part main body 22.

As described above, the optical waveguide 12 13 of the waveguide type optical element 2 and the core of the optical fiber 4 can be coupled.

As described in detail above, according to the coupling structure l of a waveguide type optical element and an optical fiber, the optical element fixing part 31, the coupling member fixing part 32, and the fiber fixing part 33 are fixed to the upper cover 21, in which the optical element fixing part 31, the coupling member fixing part 32, and the fiber fixing part 33 are respectively formed. Since the fixture 5 consisting of the part body 22 is used, the alignment and alignment of the optical waveguide 12, 13 of the waveguide type optical element 2 and the core of the optical fiber 4 can be easily and highly accurately performed, and the reliability is improved. It can improve your sexuality.

Further, since the optical waveguide 12.13 of the waveguide type optical element 2 and the core of the tip fiber 4 are coupled via the coupling member 3 having a larger diameter than the optical fiber 4, the optical waveguide 12.13 of the waveguide type optical element 2 is connected to the core of the tip fiber 4. +
The alignment and alignment of the cores of optical fibers 3 and 4 can be performed with high precision, greatly improving reliability.
I can make you do it. In addition, since the joint part with the optical waveguides 12 and 13 is large, it is not affected by stress caused by shrinkage of other members or adhesives, and stress is evenly applied to the circumference from the surroundings, causing local deformation. The effect of this stress is also small). Therefore, the influence of thermal expansion can be removed and the temperature characteristics can be reduced.

"Effects of the Invention" As described above in detail, according to the coupling structure of the waveguide type optical element and the optical fiber of the present invention, the Moeki fixture is capable of fixing the optical element for fixing the waveguide type optical element. a coupling member fixing part provided in the front part of the optical waveguide of the optical element fixing part to fix the coupling member Flf; and a coupling member fixing part provided in the front part of the coupling member fixing part to activate the optical fiber in the Since a fixed fiber fixing part is provided, the optical waveguide of the waveguide element f and the core of the optical fiber can be aligned and aligned easily and with high precision, and reliability can be improved.

In addition, since the optical waveguide of the waveguide type optical element and the core of the optical fiber are connected via a joining member having a larger diameter than the optical fiber J,
The alignment and alignment of the optical waveguide of the waveguide type optical element and the end fiber 1' can be performed more easily and with high precision.
Reliability can be significantly improved. In addition, since the coupling part with the optical waveguide is large, it is not affected by stress caused by shrinkage of other members or contact materials, and the stress is applied evenly to the circumference from the surrounding area. Deformation is difficult to occur and the influence of this stress is small. Therefore, the influence of thermal expansion can be eliminated and the temperature characteristics can be reduced.

As described above, we provide a coupling structure for waveguide optical elements and optical fibers that can be assembled and adjusted easily and with high precision, improve reliability, and eliminate the effects of thermal expansion. I can do that.

[Brief explanation of the drawing]

1 to 5 are views showing an embodiment of the present invention, in which FIG. 1 is an overall perspective view of a coupling structure between a waveguide type optical element and an optical fiber, and FIG. 2 is an optical fiber and a coupling member. 3 is a perspective view of the entire coupling structure between the waveguide type optical device and the optical fiber after assembly, FIG. 4 is a sectional view taken along the line ■-■ in FIG. 3, and FIG. The figure is In-Il in Figure 3.
FIG. 1. Coupling structure of waveguide type optical element and optical fiber, 2. Waveguide type optical element, 3 Coupling member, 3a.
・One end, 3b The other end, 4 ・・
...Optical fiber, 4a, one end, 5
・Fixing tool, 11 ・・ Substrate, 12.13 ・・ Optical waveguide, 21 ・・ Top cover, 22-・ ・ Fixing part main body, 31 ・ Optical element fixing part, 32 ・ Coupling member fixing part, 33 ・Fiber fixing part.

Claims (1)

[Claims] A structure in which an optical waveguide of a waveguide type optical element and a core of an optical fiber are coupled via a coupling member having a diameter larger than that of the optical fibers to be joined using a fixture, the fixture being an optical element fixing part for fixing the optical element; a coupling member fixing part provided in the front part of the optical waveguide of the optical element fixing part to fix the coupling member; and a coupling member fixing part provided in the front part of the coupling member fixing part to fix the coupling member. a fiber fixing part for fixing a fiber, the waveguide type optical element, the coupling member, and the optical fiber are respectively fixed to the fixture, and the optical waveguide of the waveguide type optical element and the core of the coupling member are fixed. A coupling structure of a waveguide type optical element and an optical fiber, characterized in that the waveguide type optical element and the optical fiber are coupled by aligning and aligning the cores of the optical fiber.