JPH0363608A - Fiber worked type optical device - Google Patents

Abstract

PURPOSE:To easily form a fiber worked type optical device by fixing a 1st spherical tip fiber to a slantingly polished fiber on a substrate at such an angle that light is incident with high efficiency and fixing a 2nd spherical tip fiber on its axis of reflection. CONSTITUTION:The end surface of the slantingly polished fiber 8 is fixed so as to be perpendicular to the substrate 10 and the spherical tip optical fiber 2 is fixed to the substrate 10 at the set angle where the projection light of the 1st spherical tip fiber 2 is incident on the reflecting surface with high efficiency. Then, the 2nd spherical tip fiber 4 is fixed on the optical axis where the light projecting from the spherical tip optical fiber 2 is reflected by the reflecting surface of the fiber 8. Consequently, the projection light can be made incident excellently on the slantingly polished fiber 8 without reference to the working accuracy of the tip part of the spherical tip fiber 2 and light which is reflected by a function film 6 is easily made incident on the fiber 4 by position adjustment to easily manufacture the fiber worked type optical device.

Description

[Detailed Description of the Invention] Summary This invention relates to a fiber-processed optical device mainly formed by processing the end portion of an optical fiber, and aims to provide a fiber-processed optical device that is easy to manufacture. first and second spherical fibers with outer diameters, and slanted fibers with the same outer diameter as the first and second spherical fibers with functional films formed on the end faces polished obliquely with respect to their central axes. a polished fiber and a substrate having a flat surface, the diagonally polished fiber is fixed to the flat surface of the substrate such that the end face of the diagonally polished fiber is perpendicular to the flat surface of the substrate, and the first The first spherical fiber is fixed to the flat surface of the substrate by setting an incident angle so that the light emitted from the spherical fiber enters the obliquely polished fiber with high efficiency, and the first spherical fiber is fixed to the flat surface of the substrate. The second spherical fiber is fixed to the flat surface of the substrate so that the second spherical fiber is located on the optical axis of the reflection of light emitted from the obliquely polished fiber at the end surface of the obliquely polished fiber.

INDUSTRIAL APPLICATION FIELD The present invention relates primarily to a fiber-processed optical device formed by processing the end portion of an optical fiber.

Typical forms of optical devices such as optical couplers and optical multiplexers/demultiplexers include micro-optical type devices constructed using optical elements such as lenses and half mirrors, and waveguide type devices.

However, especially when the optical transmission line is a single mode fiber, if it is a micro-optical system type or a waveguide type, there is a large loss when converting the optical beam or when connecting with the optical transmission line. In some cases, a fiber-type optical device that can be directly connected to an optical transmission line is advantageous.

Fiber-type optical devices are manufactured by two types: fiber-fused optical devices, which are formed by fusing and stretching multiple optical fibers installed in parallel, and fiber-processed optical devices, which are formed by polishing the end faces of fibers. It is broadly divided into type optical devices. The former requires fusion, etc. in the middle of the optical fiber, and is therefore more difficult to mass-produce than the latter, but the latter is also not necessarily easy to manufacture. For this reason, there is a demand for easier manufacturing of fiber-processed optical devices.

Prior Art FIG. 5 shows an example of a fiber processing type optical sonicator as a prior art. This fiber processing type optical sonicator consists of a first optical fiber 102 having a filter film 104 formed on the end face polished obliquely with respect to its central axis, and second and third optical fibers having end faces polished into a model. and an optical fiber 106.108,
It is constructed by joining the end faces of each fiber. For example, by introducing the wavelength-multiplexed light into the second optical fiber 106, the wavelength-multiplexed light is transmitted through the filter film 104 and the first
The light propagating through the optical fiber 102 and the filter film 10
A demultiplexing function is achieved by separating the light reflected by the optical fiber 4 and the light propagating through the third optical fiber 108.

Problems to be Solved by the Invention For example, in the conventional fiber-processed optical device shown in FIG. In order for the light from the second optical fiber 106 introduced and reflected by the filter film 104 to be effectively introduced into the third optical fiber 108, it is necessary to
Regarding the model processing of the 06°108 end and the optical axis alignment of each fiber, the fiber core diameter (for example, 5 μm
) is required, and a positional accuracy of the order of magnitude smaller than that of
Not easy to manufacture.

The present invention was created in view of such technical problems, and aims to provide a fiber processing type optical device that is easy to manufacture.

Means for Solving the Problems The configuration of the fiber-processed optical device of the present invention will be explained with reference to the principle diagram shown in FIG.

The fiber processing type optical device of the present invention includes first and second spherical tip fibers 2.4 having the same outer diameter and having curved end surfaces.
and first and second spherical tipped fibers 2.4 each having a functional film 6 formed on the end face polished obliquely with respect to its own central axis.
It includes an obliquely polished fiber 8 having the same outer diameter as , and a substrate 10 having a flat surface.

Then, the diagonally polished fiber 8 is attached to the substrate 10 so that the end face of the diagonally polished fiber 8 is perpendicular to the flat surface of the substrate 10.
The first spherical fiber 2 is fixed on a flat surface of the substrate 10 and the incident angle is set so that the light emitted from the first spherical fiber 2 enters the obliquely polished fiber 8 with high efficiency. The second spherical fiber 4 is fixed on a flat surface, and the second spherical fiber 4 is positioned on the optical axis of reflection of the light emitted from the first spherical fiber 2 at the end face of the obliquely polished fiber 8. is fixed to the flat surface of the substrate 10.

First and second tipped fibers 2 whose working end surfaces are curved.
．． 4, the first and second tip fibers 2
, 4, a condensing effect occurs for the emitted light or the incident light of the first
The tip of the second spherical fiber 2° 4 can be separated from the end face of the obliquely polished fiber 8. As a result, regardless of the processing precision of the tips of the first and second spherical fibers 2.4, the light from the first spherical fiber 2 that has passed through the functional film 6 can be incident on the obliquely polished fiber 8. Furthermore, the light from the first spherical fiber 2 reflected by the functional film 6 can be made to enter the second spherical fiber 4 in a good manner. That is, in the conventional technique explained with reference to FIG. .4 Despite the slight variation in the processing accuracy of the tapered spherical portion, the first and second spherical tip fibers 2°4
By adjusting the position of the optical fiber, it is possible to provide a fiber-processed optical device with the required functions without increasing loss. In this case, the end face of the obliquely polished fiber 8 is
An obliquely polished fiber 8 is fixed to the flat surface of the substrate 10 so as to be perpendicular to the flat surface of the substrate 10, and first and second tipped fibers 2.4 having the same outer diameter as this obliquely polished fiber 8 are also fixed. Since it is fixed to the flat surface of the substrate 10,
The optical axis of each fiber is always located on the same plane, so
When fixing each fiber, the position can be adjusted with each fiber in close contact with the flat surface of the substrate 10,
Easy to manufacture.

Example Embodiments of the present invention will be described below based on the drawings.

In the configuration shown in FIG. 1, the first and second tip fibers 2.4 can be created as follows. First, a midway portion of the optical fiber is heated with a burner such as a 02 Hz burner, and when it becomes soft, it is stretched and cut. Then, the cut portion is further heated to form a tip with a smooth curvature due to the surface tension of the fused silica. For example, by setting the radius of curvature of the tip to about 30 μm, good light collection can be achieved.

Polishing in producing the obliquely polished fiber 8 is preferably performed by holding a plurality of optical fibers between suitable supports. By doing so, it is possible to obtain a plurality of obliquely polished fibers in one polishing operation, and it is also easy to obtain a flat polished surface.

The functional film 6 can be formed on the end face of the obliquely polished fiber 8 by depositing a thin layer such as a dielectric multilayer film having various functions such as a filter function, a coupler function, and a polarization separation mechanism.

Now, in FIG. 1, the optical axis of the first spherical fiber 2 is ○A11, the optical axis of the second spherical fiber 4 is ○A2, the optical axis of the obliquely polished fiber 8 is OAs, and the optical axis OA +
The angle between the optical axis ○A2 and the optical axis OAs is θo1, and the angle between the optical axis ○A1 and the optical axis OAs is θ, and the optical axis 0. Assuming that the angle between As and the polished surface of the obliquely polished fiber 8 is α, the condition that the loss between the first spherical fiber 2 and the obliquely polished fiber 8 is minimized is the incidence at the polished surface of the obliquely polished fiber 8. From Snell's law for angles and angles of refraction, 5in(θo/2) = n 5in(θ./2-θ),
- (1). On the other hand, α=π/2−θ. /2+θ...(2)
For example, θ. If the refractive index n=1.46, then θζ16°, and α
It becomes ζ61'.

When attempting to fix each optical fiber to a substrate while satisfying such conditions, two methods can be considered. First of all
The second method is a method in which the position of each fiber is adjusted while monitoring the coupled optical power after temporarily positioning so that the above conditions are roughly satisfied.
This is a method in which a guide that accurately satisfies the above conditions is formed on the substrate in advance. The first method will be explained with reference to FIG. 2, and the second method will be explained with reference to FIG.

In FIG. 2, each optical fiber 2.4.
8 are each supported by an independently movable fine movement table (not shown). The wavelength λ from the light source 14 is connected to the first spherical fiber 2 by an optical coupler 12 such as an optical coupler.
1 and the light of wavelength λ2 (≠λ1) from the light source 16 are wavelength-multiplexed and incident. 18 and 20 are optical power meters connected to the obliquely polished fiber 8 and the second spherical fiber 4, respectively. It is assumed that the functional film 6 is a filter film and has a function of transmitting light with a wavelength of λ2 and reflecting light with a wavelength of λ2. When using such an adjustment system,
Since the measured value of the optical power meter 18.20 becomes maximum when formulas (1) and (2) are satisfied, each optical fiber 2. It is sufficient to perform the position adjustment in step 4.8 and fix it with adhesive or the like.

When a guide is formed on the substrate in advance to eliminate the need for such adjustment, this guide is required to have extremely high positional accuracy. For this reason, a guide manufacturing method as shown in FIG. 3 is suitable. First of all, same one! As shown in I(a), a substrate 10 having a flat surface 10a is formed from Si. Next, as shown in FIG.
A layer 22 of SiO is formed on the optical fiber a by CVD, for example, to a thickness greater than the radius of the optical fiber. After forming a mask (not shown) having a mask pattern corresponding to the guide formation position on the 5iot layer 22, the Si02 layer 22 is
By selectively etching, as shown in the same figure (C),
Guide 22A for the first spherical fiber 2, guide 22B for the second spherical fiber 4, and guide 2 for the obliquely polished fiber 8
Form 2G. In this case, the shape of each guide is 0.1μ
It has an accuracy of about m.m and also maintains the flatness of the flat surface of the substrate 10, so each fiber is
2A,B.

The position of each fiber can be determined by simply adjusting the length of the fiber and fitting the fiber into the fiber.

The durability of the fiber-processed optical device produced by the first or second method is improved by housing it in a housing as shown in FIG.

That is, the fiber-processed optical device of the embodiment is housed and fixed in a sealable casing 30, and the holes through which each fiber is led out are filled with adhesive 26 to create a sealed structure. In the figure, reference numeral 24 indicates a coating for each optical fiber, and reference numeral 28 indicates an adhesive used to fix each fiber to the substrate 10. According to such a structure, the opposing part (optical coupling part) of each fiber
In addition, since the coating 24 of each fiber is fixed to the housing 30, the mechanical strength is sufficient.

As described in detail, the present invention has the advantage that it is possible to provide a fiber-processed optical device that is easy to manufacture.

[Brief explanation of drawings]

FIG. 1 is a diagram of the principle of the present invention, FIG. 2 is an explanatory diagram of the manufacturing procedure of a fiber-processed optical device in an embodiment, and FIG. 3 is an explanatory diagram of another manufacturing procedure of a fiber-processed optical device in an embodiment. FIG. 4 is a cross-sectional view showing a state in which a fiber-processed optical device is housed in a housing in an embodiment, and FIG. 5 is an explanatory diagram of the prior art. 2... First spherical tip fiber, 4... Second spherical tip fiber, 6... Functional film, 8... Obliquely polished fiber, 10... Substrate.

Claims (1)

[Claims] First and second spherical fibers (2, 4) having the same outer diameter and having curved end surfaces, and a functional film ( and a substrate (10) having a flat surface; and a substrate (10) having a flat surface; The end face of (8) is the substrate (10)
The obliquely polished fiber (8) is fixed to the flat surface of the substrate (10) so as to be perpendicular to the flat surface of the substrate, so that the light emitted from the first spherical fiber (2) can be highly efficiently The first spherical fiber (2) is attached to the substrate (10) with the angle of incidence set so that it enters the obliquely polished fiber (8).
is fixed to the flat surface of the first spherical fiber (2), and the second fiber is fixed on the optical axis of the reflection of the light emitted from the first spherical fiber (2) at the end face of the obliquely polished fiber (8).
A fiber-processed optical device characterized in that the second spherical fiber (4) is fixed to the flat surface of the substrate (10) such that the second spherical fiber (4) is positioned.