JP2003315612A - Optical collimator, and method of assembling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical collimator, which eliminates the need to pass light to an optical fiber unlike a conventional assembling method, is easy to assemble and has high reliability to optical alignment, and an assembling method thereof. <P>SOLUTION: The optical collimator is provided with a thin tube 11, a glass- made partially spherical lens 12 fixed in an inner hole 11b except an insertion port 11a and having translucent spherical surfaces 12b and 12c with almost the same center of curvature and an adhesive 13 for bonding the partially spherical lens 12, an axial deviation between the center axis of the thin tube and the optical axis of the partially spherical lens is within 5 μm; and a capillary tube fixed having an axial deviation of within 1.5 μm between the outer peripheral surface 14a and the core center of the end surface 15a of the optical 15 is inserted into the insertion portion 11a and the end surface 15a is fixed to a position within ±40 μm of the focal point position of the partially spherical lens 12. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber for optical communication and a lens which are optically coupled to each other so that light emitted from the optical fiber is collimated or collimated by a lens. And an assembling method thereof.

[0002]

2. Description of the Related Art Many optical devices are used in constructing a high speed and large capacity optical fiber communication system. Among them are those that extract optical signals of arbitrary wavelengths from optical signals in which multiple wavelengths are multiplexed, and those that use optical crystals to match the phase of optical signals. A large number of optical collimators that convert parallel optical signals into parallel light are used.

In manufacturing a conventional optical collimator, as shown in FIG. 12, a capillary tube 3 with an optical fiber 2 is first fixed to a thin tube 1 and the helium-neon laser light of the visible light source is passed from the optical fiber 2 to the capillary tube 3. The position of the lens 5 is aligned while the collimated state of the laser light L is emitted on the projection stage 6 so that the lens 5 which has emitted L and is grasped on the precision stage 4 has an optically appropriate positional relationship. After that, it is fixed to the thin tube 1 with an epoxy adhesive 7.

[0004]

In the conventional assembling method as described above, since the laser light L is actually emitted from the optical fiber 2, the light source and the optical fiber 2 must be connected with high accuracy of several μm level. However, there is a problem that the workability is very poor because it takes too much time for preparation for manufacturing the optical collimator such as the work related to the alignment and the processing of the optical fiber 2.

Further, in the conventional assembling method, the actual gripping margin of the lens 5 is not several millimeters, and the optical position is required to have a high accuracy of several μm or several μm. There is also a problem that workability becomes poor.

Further, since there is a gap between the lens 5 and the thin tube 1 during the optical position alignment, the adhesive 7 is used after the positioning.
There is a problem that the position of the lens 5 or the like is easily displaced due to the volume contraction of the adhesive 7 when the adhesive is cured and fixed.

The present invention has been made in view of the above problems, and it is not necessary to pass light to an optical fiber at the time of assembling like a conventional optical collimator assembling method, and the assembling is easy. An object of the present invention is to provide an optical collimator having high reliability for optical alignment and an assembling method thereof.

[0008]

The optical collimator according to the present invention comprises a thin tube and both ends of a cylindrical portion made of glass having a substantially uniform refractive index, which is fixed in the inner hole of the thin tube leaving an insertion portion of a predetermined length. Is equipped with a partial spherical lens having a light-transmitting spherical surface with substantially the same center of curvature, and an adhesive for bonding the partial spherical lens to the thin tube, and the axial deviation amount between the central axis of the thin tube and the optical axis of the partial spherical lens is 5 μm. And the optical fiber end surface of the capillary having the optical fiber fixed in the inner hole and the axial deviation between the outer peripheral surface and the core center of the optical fiber end surface in the insertion part of the lens component is within 1.5 μm. Lens focal position ± 40μ
It is characterized in that it is fixed at a position within m.

When the axial deviation amount between the central axis of the thin tube and the optical axis of the partial spherical lens constituting the optical collimator of the present invention is within 5 μm, as shown in FIG. The outgoing light bending θ within 0.2 ° desired with respect to the central axis of the ten thin tubes can be obtained. However, when the amount of axial deviation between the central axis of the thin tube and the optical axis of the partial spherical lens exceeds 5 μm, as shown in FIG. 1 (B), the emitted light L is desired with respect to the central axis of the thin tube of the optical collimator 10. The output light bending θ within 0.2 ° cannot be obtained.

Further, as a capillary tube in which the optical fiber 15 to be inserted into the optical collimator 10 of the present invention is fixed in the inner hole, the axial deviation amount between the outer peripheral surface and the core center of the end surface of the optical fiber 15 is within 1.5 μm. It is important to be there. When the axial deviation amount between the outer peripheral surface of the capillary having the optical fiber fixed to the inner hole and the core center of the end surface of the optical fiber exceeds 1.5 μm,
As shown in (B), the outgoing light cannot obtain a desired outgoing light bending θ within 0.2 ° with respect to the central axis of the thin tube, and the distribution of the beam intensity of the outgoing light L is eccentric, resulting in a desired optical signal. The coupling efficiency of is not obtained.

When there is a deviation in the coaxiality between the inner surface of the thin tube, the optical axis of the partial spherical lens, and the optical axis of the optical fiber in the capillary tube, as shown in FIG. Therefore, depending on the application used, the allowable amount of axial misalignment is determined within the range of allowable angles, but if this angle becomes too large, parallel light will not be returned to the optical fiber by another optical collimator. Then, the light amount is attenuated. For example,
In the case of an optical collimator made of LaSF015, which is a glass material with a refractive index of about 1.8, and uses a partial spherical lens with a radius of curvature of 1.75 mm, it is necessary to achieve an insertion loss of 0.2 dB or less, which is a general coupling characteristic. The above angle to 0.
It is necessary to press within 1 °. Further, in that case, the deviation tolerance of the optical axis of the partial spherical lens and the optical axis of the optical fiber 15 is about 4 μm.

As a thin tube, when a capillary tube with an optical fiber is inserted into its inner surface, it is automatically aligned.
It is important that the inner surface of the thin tube and the optical axis of the partially spherical lens are arranged coaxially, and that the inner surface of the thin tube and the capillary tube with the optical fiber are fitted to each other appropriately. At this time, if the coaxiality between the inner surface of the thin tube, the optical axis of the partial spherical lens, and the optical fiber in the capillary tube is excessively shifted, an angle is generated in the obtained parallel light. Therefore, the amount of axial deviation of each element is determined by the range in which the angle is allowed according to the purpose of use. When fixing a capillary tube with an optical fiber and a capillary tube by welding, it is preferable to use stainless steel having excellent weldability and weather resistance.

When the end face of the optical fiber is fixed at a position within a focal position of the partial spherical lens of ± 40 μm, a pair of optical collimators are arranged to face each other to transmit and receive an optical signal, as shown in FIG. Further, when the end face of the optical fiber is arranged at the focal point FP of the partial spherical lens, the beam waist BW of the emitted light is formed at the position as shown in FIG. When the end face of the optical fiber is arranged at a position closer to the focal point FP of the partial spherical lens, the beam waist BW of the emitted light is formed at a position closer to the position of the partial spherical lens as shown in FIG. 2C. Focal position F of partially spherical lens
When it is arranged at a position closer than 40 μm than P, the beam waist BW is not formed and spreads. On the other hand, when the end face of the optical fiber is arranged at a position farther than the focal point FP of the partial spherical lens, the beam waist BW of the outgoing light is formed at a position far from the partial spherical lens position as shown in FIG. 2D. When the end face is arranged at a position 40 μm or more farther from the focal position FP of the partial spherical lens, the beam waist BW is not formed and spreads. In the optical collimator of the present invention, the end surface of the optical fiber is set to the focal position ± of the partial spherical lens.
It is important to fix at a position where the distance is within 40 μm.

As the partial spherical lens used in the present invention, any material can be used as long as it is made of optical glass or the like having a substantially uniform refractive index and can be processed into a true spherical shape to produce a partial spherical lens having high focus accuracy. Therefore, in order to reduce the size and the diameter of the optical collimator, the partial spherical lens manufactured by grinding the periphery of the partial spherical lens having high sphericity is suitable. Since the optical axis of the partial spherical lens is an axis that passes through the center of curvature of the lens and is parallel to the central axis of the thin tube, it is not affected by the side surface shape when grinding the periphery, the inclination of the processing axis, the axial deviation, or the like. Further, as the glass used for the partially processed partially spherical lens, BK7, K3, TaF of optical glass are used.
3, LaF01, LaSF015, etc. are preferably used.

The optical collimator of the present invention is characterized in that the partial spherical lens has a refractive index of 1.7 or more.

The partial spherical lens is originally a lens having spherical aberration, but when the refractive index is low, the spherical aberration becomes large, and the partial spherical lens condenses the optical signal emitted from the end face of the optical fiber or the end face of the optical fiber. The coupling efficiency of the received optical signal is reduced. The partial spherical lens used in the optical collimator of the present invention preferably has a refractive index of 1.7 or more.

In the optical collimator of the present invention, the distance between the end face of the optical fiber and the spherical surface of the partial spherical lens, that is, the distance obtained by subtracting the radius of curvature R of the partial spherical lens from the focal length f of the partial spherical lens is 0.1 mm or more. And the distance between the end surface of the optical fiber and the spherical surface of the partial spherical lens is 0.1.
It is preferably 5 mm or more.

In the optical collimator, when the distance between the end surface 15a of the optical fiber 15 and the spherical surface of the partial spherical lens 12 becomes less than 0.1 mm, such as when the radius of curvature R of the partial spherical lens is small, as shown in FIG. Light L reflected from the spherical surface of the lens
A large amount of b returns to the end face 15a of the optical fiber 15 and becomes noise. On the other hand, if the focal length is longer than +40 μm, the beam waist BW is not formed and spreads. As the distance between the end face of the optical fiber and the spherical surface of the partial spherical lens,
It is important that the distance is 0.1 mm or more, and it is preferable that the distance between the optical fiber end surface and the spherical surface of the partial spherical lens is 0.15 mm or more in order to reduce the reflected light re-incident on the optical fiber end surface.

The optical collimator of the present invention is characterized in that the thin tube is made of glass or crystallized glass.

Any thin tube made of glass or crystallized glass can be used as long as it has a coefficient of thermal expansion close to that of a partially spherical lens or a capillary tube, and the material of the thin tube can control the state of crystal precipitation. For example, the continuous molding method is suitable because it can be obtained with high accuracy and at low cost.

The optical collimator of the present invention is characterized in that the thin tube is a split sleeve.

Regarding the inner diameter of the split sleeve, it is important that the fit with the capillary tube with the optical fiber has a tight fit relationship. The dimensional difference between the two affects the deviation between the inner surface of the thin tube and the optical axis of the partially spherical lens. When a split sleeve having an inner diameter smaller than that of a capillary tube with an optical fiber by about several μm is used for the thin tube, this dimensional difference can be eliminated, which is effective. The split sleeve may be made of metal, zirconia ceramics, or the like.

The optical collimator of the present invention is characterized in that the split sleeve is made of metal.

The split sleeve is preferably made of metal, which has low hardness and does not damage the surface of the partial spherical lens or the capillary tube with the optical fiber and can prevent dust generation. As the metal material, phosphor bronze or stainless steel, which has high dimensional reproducibility, is suitable.

The optical collimator of the present invention is characterized in that the adhesive is an epoxy resin or a low melting point glass frit mixed with a filler made of one or more of ceramic, glass or metal.

The epoxy adhesive generally used for assembling the collimator undergoes volume contraction of about 20% during curing. In order to prevent the positional deviation of the partially spherical lens due to such contraction, it is effective to mix fine particles or filler of ceramic or metal with the adhesive. In addition, by mixing the filler, thixotropic properties are imparted, which is effective in preventing dripping and improving the strength of the adhesive.

In the optical collimator of the present invention, an inner thin tube having an inner hole having a predetermined inner diameter is inserted and arranged in the insertion portion of the thin tube, and the spherical surface of the partial spherical lens is perpendicular to the tube axis of the inner thin tube with a predetermined accuracy. It is characterized in that it is adhesively fixed in a state where the end faces are in contact with each other.

As an inner thin tube having an inner hole having a predetermined inner diameter, a fitting gap with respect to the insertion portion of the thin tube has a gap of several μm.
It has an outer diameter within a m or a tight fit relationship, has an inner diameter that is a few μm larger than a capillary tube without blocking outgoing / incoming light from an optical fiber, and with respect to the tube axis of the inner tube. It can be used as long as it has a right angle end face with a predetermined accuracy of several "to several".

The optical collimator of the present invention is substantially required because the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is smaller than the optimum value calculated by the refractive index and spherical radius of the partial spherical lens. The beam waist position is within ± 5 mm of a predetermined value within the working distance range.

When the beam waist position of the collimator beam of the light emitted from the optical collimator deviates from the predetermined value ± 5 mm, the coupling efficiency is lowered due to the wave characteristic of the light. By adopting the above configuration, the emitted collimator beam can be transmitted to the optical fiber on the light receiving side with high coupling efficiency, and high-quality communication performance can be maintained. In the optical collimator of the present invention, the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is smaller than the optimum value calculated by the refractive index and the spherical radius of the partial spherical lens so that the collimator beam of the emitted light can be narrowed down. The beam waist position is within ± 5 of the specified value within the required working distance range.
It is important to be within mm.

The method of assembling the optical collimator according to the present invention is as follows.
A thin spherical tube, a partial spherical lens having translucent spherical surfaces having substantially the same center of curvature at both ends of a cylindrical portion made of glass having a substantially uniform refractive index and fixed in the inner hole of the thin tube leaving an insertion portion of a predetermined length.
An adhesive for adhering the partial spherical lens to the thin tube is provided, and the axial deviation amount between the central axis of the thin tube and the optical axis of the partial spherical lens is 5
The lens component having a diameter of within μm and the axial deviation amount between the outer peripheral surface and the core center of the end face of the optical fiber is 1.
A method of assembling an optical collimator, wherein an end of an optical fiber of a capillary having an optical fiber fixed to an inner hole within 5 μm is fixed to a position within a focal position ± 40 μm of a partial spherical lens,
When fixing the capillary tube to the insertion part of the lens component, the distance between the end face of the optical fiber and the light-transmitting spherical surface of the partial spherical lens is measured from the outside to perform positioning between the capillaries.

According to the assembling method of the present invention, the inner thin tube having the outer diameter that is fitted into the inner hole of the thin tube has a clearance fit or a tight fit with a gap of several μm or less is inserted. Fixing the end face perpendicular to the tube axis with a predetermined accuracy at a predetermined position is important for accurate positioning of the partial spherical lens. It should be noted that the capillary is provided with an extra length sufficient to hold it with sufficient strength when a capillary with an optical fiber is arranged at an appropriate distance from the partial spherical lens.
Further, if the positional deviation during curing does not cause an optical problem, the filler may not be mixed.

Further, in the method of assembling the optical collimator of the present invention, the thin tube has the penetrating portion at a position where the position where the spherical surface of the partial spherical lens and the end surface of the optical fiber are at a predetermined distance can be observed, It is characterized in that the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is measured from the outside by using parallel measuring light to determine the position.

A metal sleeve with a peephole is used so that the end surface of the partially spherical lens on the optical fiber side and the end surface of the optical fiber on the lens side can be observed. To get parallel light,
The end face of the optical fiber must be placed at the focal position of the partial spherical lens, but since it is possible to observe the same part,
This can be easily adjusted by measuring the distance between the apex of the spherical surface of the partial spherical lens and the end face of the optical fiber with a measuring device such as a laser beam length measuring machine or a microscope.

In the method of assembling the optical collimator of the present invention, the thin tube is made of a transparent body capable of externally measuring the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber, and the partial spherical surface is obtained by using substantially parallel measuring light. It is characterized in that the distance between the spherical surface of the lens and the end face of the optical fiber is measured from the outside to determine the position.

A transparent glass tube or the like through which light and magnetism can be observed, which allows observation of the end surface of the partial spherical lens on the optical fiber side and the end surface of the optical fiber on the partial spherical lens side, is used.
In order to obtain parallel light, it is necessary to place the end surface of the optical fiber at the focal point of the partial spherical lens, but it is possible to observe the same part by using a thin tube made of a transparent body. This can be easily adjusted by measuring the distance between the apex of the spherical surface of the partial spherical lens and the end face of the optical fiber with a measuring machine such as a machine or a microscope. Further, after the dimension adjustment, the present invention and the capillary tube with the optical fiber are fixed by an adhesive or welding, but at that time, since the same portion can be observed, it is confirmed that there is no problem in the light passage region. It is also suitable for When used as a tube, the material of the thin tube is preferably borosilicate glass or the like, which has good heat workability and excellent weather resistance that transmits light and magnetism.

In the method of assembling the optical collimator of the present invention, the thin tube and / or the inner thin tube has a thickness of 1 mm and a wavelength of 350 to 500.
It is characterized by being made of transparent glass which transmits 50% or more of light of nm.

When the thin tube and / or the inner thin tube transmits light having a thickness of 1 mm and a wavelength of 350 to 500 nm by 50% or more, the near-ultraviolet ray to blue visible ray having sufficient sensitivity for curing reaction of the photocurable adhesive is sufficient. The transparent glass may be borosilicate glass, quartz glass or the like, in which the content of impurities such as iron that reduces the transparency is suppressed.

In the method of assembling the optical collimator of the present invention, the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is an optimum value calculated by the refractive index of the partial spherical lens and the spherical radius of the transparent spherical surface. The beam waist position is set within ± 5 mm of a predetermined value within a working distance that is substantially required.

When the beam waist position of the collimator beam of the light emitted from the optical collimator deviates from the predetermined value ± 5 mm, the quality of the optical signal as a wave deteriorates. In the optical collimator of the present invention, the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is set to be smaller than the optimum value calculated by the refractive index and spherical radius of the partial spherical lens so that the collimator beam of the emitted light can be narrowed down. The beam waist position within the required working distance by ±
It is important to set the distance within 5 mm.

In the structure of the collimator lens component of the present invention, the partial spherical lens is attracted to the inner capillary having the same outer diameter as the capillary with the optical fiber and having the hole coaxial with the outer diameter,
It is inserted into a thin tube and fixed by filling the gap between the partial spherical lens and the thin tube with an adhesive and curing it, then stopping the adsorption and pulling out the inner thin tube, so that the thin tube inner hole and the partial spherical lens can be easily attached. It is possible to realize highly accurate coaxiality.

In the optical collimator of the present invention, when the capillary with an optical fiber is inserted into the inner surface of the thin tube, the inner surface of the thin tube and the optical axis of the partial spherical lens are coaxially arranged so that the capillary is aligned without doing anything. In addition, the inner surface of the thin tube and the capillary tube with the optical fiber are appropriately fitted to each other. At this time, if the coaxial relationship between the inner surface of the thin tube, the optical axis of the partially spherical lens, and the capillary tube with the optical fiber is deviated, an angle is generated in the obtained parallel light. Therefore, the amount of axial deviation is determined within the allowable range of the same angle according to the intended use. Also,
Other thin tubes may be used that have the same effect by using a spacer that adjusts the distance between the apex of the partial spherical lens and the end surface of the optical fiber or a stopper provided on the inner surface of the thin tube in a protruding shape. .

[0043]

In the optical collimator of the present invention, the center of curvature is substantially the same at both ends of the thin tube, which is fixed to the inner hole of the thin tube leaving an insertion portion of a predetermined length and made of glass having a substantially uniform refractive index. A lens component including a partial spherical lens having a light-transmitting spherical surface and an adhesive for bonding the partial spherical lens to a thin tube, wherein an axial deviation amount between the central axis of the thin tube and the optical axis of the partial spherical lens is within 5 μm, In the insertion part of the lens component, the axial deviation between the outer peripheral surface and the core center of the end face of the optical fiber is within 1.5 μm, and the end face of the optical fiber of the capillary with the optical fiber fixed in the inner hole is within ± 40 μm of the focal point of the partial spherical lens. Since the light is fixed at the position, it is possible to manufacture an optical collimator in which the emitted light has a desired bending of the emitted light within 0.2 °.

Further, in the optical collimator of the present invention, since the partial spherical lens has a refractive index of 1.7 or more, spherical aberration is reduced and parallel light having high coupling efficiency and outgoing light bending can be obtained.

In the optical collimator of the present invention, the distance between the end surface of the optical fiber and the spherical surface of the partial spherical lens is 0.1 mm or more, preferably the distance between the end surface of the optical fiber and the spherical surface of the partial spherical lens is 0.15 mm or more. Therefore, the return light reflected from the spherical surface of the partial spherical lens and incident on the optical fiber can be significantly reduced, and the fluctuation of the optical signal characteristics becomes small within the working distance (working distance).

Since the thin tube of the optical collimator of the present invention is made of glass or crystallized glass, it is possible to use a highly accurate and inexpensive thin tube.

In the optical collimator of the present invention, since the thin tube is the split sleeve, the inner diameter of the split sleeve has a relationship of fitting and fitting with the capillary tube having the optical fiber, and the inner surface of the thin tube and the partial spherical lens. It is possible to eliminate the dimensional difference between the two, which influences the deviation from the optical axis.

In the optical collimator of the present invention, since the split sleeve is made of metal, the hardness is low and the surface of the partially spherical lens or the capillary tube with the optical fiber is not damaged, and it is possible to prevent dust generation. Phosphor bronze, which has good dimensional reproducibility, enables stable fixation of partially spherical lenses and capillaries with optical fibers.

In the optical collimator of the present invention, the adhesive is an epoxy resin or a low-melting glass frit mixed with a filler made of one or more of ceramic, glass or metal. It is possible to prevent the partial spherical lens from being displaced due to, and by mixing the filler, it is possible to prevent liquid dripping and improve the strength of the adhesive.

In the optical collimator of the present invention, an inner thin tube having an inner hole of a predetermined inner diameter is inserted and arranged in the insertion portion of the thin tube, and the spherical surface of the partial spherical lens is perpendicular to the tube axis of the inner thin tube with a predetermined accuracy. Since the end faces are in contact with each other and are fixed by adhesion, the partial spherical lens and the inner thin tube are fixed to the thin tube at the correct positions within the correct allowable axial displacement.

The optical collimator of the present invention is substantially required because the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is smaller than the optimum value calculated by the refractive index and spherical radius of the partial spherical lens. Since the beam waist position is within ± 5 mm of the predetermined value within the working distance, it is possible to maintain a high-quality optical signal as a wave.

The method of assembling the optical collimator according to the present invention is as follows.
A thin spherical tube, a partial spherical lens having translucent spherical surfaces having substantially the same center of curvature at both ends of a cylindrical portion made of glass having a substantially uniform refractive index and fixed in the inner hole of the thin tube leaving an insertion portion of a predetermined length.
An adhesive for adhering the partial spherical lens to the thin tube is provided, and the axial deviation amount between the central axis of the thin tube and the optical axis of the partial spherical lens is 5
The lens component having a diameter of within μm and the axial deviation amount between the outer peripheral surface and the core center of the end face of the optical fiber is 1.
A method of assembling an optical collimator, wherein an end of an optical fiber of a capillary having an optical fiber fixed to an inner hole within 5 μm is fixed to a position within a focal position ± 40 μm of a partial spherical lens,
When fixing the capillary tube to the insertion part of the lens component, the distance between the end face of the optical fiber and the translucent spherical surface of the partial spherical lens is measured from the outside to perform positioning between the capillaries, so that the inner hole of the capillary tube The partial spherical lens can be accurately positioned with respect to.

In the method of assembling the optical collimator according to the present invention, the thin tube has the penetrating portion at a position where the position where the spherical surface of the partial spherical lens and the end surface of the optical fiber are at a predetermined distance can be observed, and the thin tube is substantially parallel. Since the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is measured from the outside using measuring light to determine the position, the end face of the optical fiber is fixed at a position where a beam waist that achieves the desired operating range is obtained with μm accuracy. Therefore, a high-performance optical collimator can be easily manufactured.

In the method of assembling the optical collimator according to the present invention, the thin tube is made of a transparent body capable of externally measuring the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber, and the partial spherical surface is obtained by using substantially parallel measuring light. Since the distance between the spherical surface of the lens and the end face of the optical fiber is externally measured to determine the position, the end face of the optical fiber can be fixed at a position where a beam waist that achieves a desired working range is obtained with μm accuracy, and high performance is achieved. An optical collimator can be easily manufactured.

In the method of assembling the optical collimator of the present invention, the thin tube and / or the inner thin tube has a thickness of 1 mm and a wavelength of 350 to 50.
Since it is made of transparent glass that transmits 50% or more of 0 nm light, the visible light of blue to near ultraviolet rays, which has a high sensitivity of the curing reaction of the photocurable adhesive, is sufficiently transmitted. An optical fiber or a capillary tube with an optical fiber can be fixed in the capillary in a short time.

In the method of assembling the optical collimator according to the present invention, the distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is more than the optimum value calculated by the refractive index of the partial spherical lens and the spherical radius of the transparent spherical surface. Beam waist position is within ± 5m of the specified value within the required working distance
Since the setting is made within m, the collimator beam can be narrowed down within the working distance, and a stable optical collimator with low insertion loss can be realized. As a result, the collimator beam of emitted light can be transmitted with high coupling efficiency, and high-quality communication performance can be maintained.

[0057]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 4 is an explanatory view of the optical collimator 10 showing an example of the present invention. In the figure, 11 is a split sleeve made of phosphor bronze as a thin tube, 12 is a partially spherical lens, 13 is an adhesive, 14 is a capillary, and 15 is an optical fiber.

As shown in FIG. 4, the optical collimator 10 of the present invention has an outer diameter of 1.60 mm, a linear split portion 11b and a penetrating portion 11c, and an inner hole 11d having an inner diameter of 1.249 m.
m is a phosphorous bronze or stainless steel split sleeve 11 having a total length of 5.5 mm, and an insert portion 11a having a length of 2.5 mm is left and fixed in the inner hole 11b of the split sleeve 11 so that the refractive index is substantially uniform. The optical disk LaSF015 is formed, and the radius of curvature R having the translucent spherical surfaces 12b and 12c with substantially the same center of curvature at both ends of the cylindrical portion 12a is 1.500 ± 0.
002 mm partial spherical lens 12 and split sleeve 11
And an adhesive 13 made of an epoxy resin for adhering the partial spherical lens 12 to the central axis of the split sleeve 11 and the optical axis of the partial spherical lens 12 is 3 μm.
An antireflection film is formed on the translucent spherical surfaces 12b and 12c of the partial spherical lens 12.

The optical collimator 10 has an axial deviation of 0.5 μm from the outer peripheral surface 14a with respect to the core center of the end face 15a of the single-mode optical fiber 15, and the outer diameter of the optical fiber 15 fixed in the inner hole 14b is 1. .249 mm ± 0.5 μm
Then, the capillary tube 14 having a total length of 5.0 mm is inserted into the insertion portion 11a in the split sleeve 11 and inclined at 8 ° with respect to the plane perpendicular to the optical axis of the optical fiber 15, and the end surface 15a on which the antireflection film is formed is formed. And the spherical surface 12b of the partial spherical lens 12 are fixed at a position where the distance d1 is 0.215 mm ± 2 μm, and the outgoing light has a desired outgoing light bending of 0.1 ° within 0.2 °. is there.

In the case of the optical collimator 10 in which the capillary tube 14 is fixed as described above, as shown in FIG. 5, the end face 15 of the optical fiber 15 inclined by the inclination angle α with respect to the plane perpendicular to the optical axis.
When an optical signal inclined by β with respect to the optical axis is incident on the partial spherical lens 12 from a, an offset W is generated between the partial spherical lens 12 and the optical axis of the light emitted from the partial spherical lens 12 with respect to the optical axis. Occurs. This offset W has a relationship as illustrated by the refractive index n3 of the partial spherical lens 12, the radius of curvature R, and the inclination angle α of the end face 15a of the optical fiber 15.

Next, four optical collimators 10 with the capillaries 14 fixed were prepared and the insertion loss and return loss were measured.

When the capillary tube 14 to which the optical fiber 15 having the inclined end face 15a is fixed is fixed to the optical collimator 10, the emitted light has an offset W of 114 μm from the optical axis of the optical fiber 15, as shown in FIG. , When the directions of the offset W do not match, FIG.
The axis misalignment loss of the optical signal occurs as shown in. Therefore, when measuring the insertion loss and return loss, set the working distance to 20
The offset positions of the pair of optical collimators 10 that are set to face each other and set to mm are adjusted as shown in FIG. 6 (B) or (C). Table 1 shows the measurement results of the insertion loss.

[0064]

[Table 1]

Regarding the above optical collimator 10,
The return loss was measured. The results are shown in Table 2.

[0066]

[Table 2]

As shown in Table 2, the return loss is the return loss.
The return loss becomes worse as the distance between the partially spherical lens and the optical fiber becomes shorter. At 0.215 ± 5 μm, the return loss is about ± 0.3 dB. That is, as expected, the return loss becomes worse as the distance between the partial spherical lens and the optical fiber becomes shorter, and the change in return loss is an average value with respect to the change of −5 μm between the partial spherical lens and the optical fiber. It is about 0.3 dB when viewed at. Further, when the relationship between the eccentricity of the partial spherical lens with respect to the sleeve and the reflection attenuation amount is obtained, if the eccentricity amount is within 5 μm, the reflection attenuation amount changes by about 0.5 dB. Furthermore, the relationship between the eccentricity of the partially spherical lens with respect to the sleeve and the insertion loss was measured. Insertion loss by fixing the light collimator on the light source side as a reference and decentering the lens of the light collimator on the light receiving side in the directions of 0 °, 90 °, 180 ° and 270 ° respectively. The eccentricity dependency of was confirmed. The results are shown in Table 3.

[0068]

[Table 3]

As can be seen from the measurement results shown in Table 3, regarding the relationship between the eccentricity of the partially spherical lens with respect to the sleeve and the insertion loss, the variation of the insertion loss in the eccentric direction is 0.
It was found to be about 01 dB.

The relationship between the eccentricity direction and the return loss was measured using a partial spherical lens with an eccentricity of 4.5 μm. Decentering direction: the direction in which the optical fiber tip approaches the optical axis of the partial spherical lens, and decentering direction: the direction in which the optical fiber tip moves away from the optical axis of the partial spherical lens.

[0071]

[Table 4]

As shown in Table 4, it was found that the eccentric direction was better than the eccentric direction. In this way, if the eccentricity amount is controlled within 5 μm, the change in return loss is
It becomes about 0.5 dB.

Next, a method of assembling the optical collimator 10 will be described.

First, as shown in FIGS. 7 (A) and 7 (B),
The split sleeve 11 is manufactured by providing a penetrating portion 11c on a split sleeve having an outer diameter of 1.60 mm and a linear split portion, and an inner hole having an inner diameter of 1.249 mm and a total length of 5.5 mm. At this time, the processing is carried out while paying attention so as not to reduce the accuracy of the split sleeve 11.

Next, as shown in FIG. 7C, there is an inner hole 17b having an outer diameter of 1.249 mm and an inner diameter of 0.68 mm, and a squareness within ± 0.1 ° with respect to the tube axis. End face 17a
The inner thin tube 17 having the is prepared.

Next, as shown in FIG. 7 (D), a spherical lens having a radius of curvature R of 1.500 ± 0.002 mm was prepared using optical glass LaSF015 having a substantially uniform refractive index, and this sphere was formed. A cylindrical portion 12a is formed by rotating the lens about the optical axis and polishing it, and the transparent spherical surface 12 is formed at both ends.
A partial spherical lens 12 having b, 12c and an annular groove 12d for filling an adhesive is prepared.

Next, as shown in FIG. 7E, the outer peripheral surface 1
The optical fiber 15 is inclined at an angle of 8 ° with respect to the plane perpendicular to the optical axis of the single mode optical fiber 15 with respect to 4a, and has an axial deviation of 0.5 μm from the core center of the end face 15a formed with the antireflection film. The outer diameter fixed to the inner hole 14b is 1.249.
A capillary tube 14 having a length of mm ± 0.5 μm and a total length of 5.0 mm is prepared.

Next, the split sleeve 1 shown in FIG.
As shown in FIG. 8 (B), the inner thin tube 17 is inserted into the insertion portion 11a of the inner hole 11d of No. 1 and the right end face 17a thereof is fixed at a position of 2.5 mm from the end face of the sleeve 11. , The partial spherical lens 12 is inserted into the inner hole 11d of the split sleeve 11, and the transparent spherical surface 12 is formed on the end surface 17a of the inner thin tube 17.
b is brought into contact to position the partial spherical lens 12,
Then, the partial spherical lens 12 is fixed to the inner hole 11d of the split sleeve 11 with an adhesive agent 13. As shown in FIG. 8C, the inner thin tube 17 is removed after the adhesive 13 is completely cured. Finally, as shown in FIG. 8D, the capillary 14 having the optical fiber 15 fixed to the inner hole 14b is inserted into the insertion portion 11a in the split sleeve 11 so that the end surface 15a and the spherical surface 12b of the partial spherical lens 12 are separated. Distance d1 is 0.215 mm
The optical collimator 10 is obtained by positioning and fixing while adhering to the position of ± 2 μm while observing and measuring through the penetrating portion 11c and adhering.

Next, another embodiment according to the present invention will be described. FIG. 9 is an explanatory diagram of an optical collimator 20 showing another example of the present invention. In the figure, 21 is a glass tube as a thin tube, 22 is a partial spherical lens, 23 is an adhesive, and 24
Indicates a glass inner tube, 25 an optical fiber, and 26 a capillary tube.

As shown in FIG. 9, another optical collimator 20 of the present invention has an outer diameter of 1.80 mm, an inner diameter of the inner hole 21b of φ1.005 mm + 0.01 / -0 mm, and a total length of 6.
The cylindrical portion 2 is composed of a 0 mm glass thin tube 21 and an optical glass LaSF015 having a substantially uniform refractive index, which is fixed in the inner hole 21b of the glass thin tube 21 except for the insertion portion 21a having a predetermined length.
2a has translucent spherical surfaces 22b, 22 having substantially the same center of curvature at both ends.
A partial spherical lens 22 having a radius of curvature R of c of 1.25 ± 0.0015 mm, a diameter of φ0.98 mm, and an eccentricity of the central axis of the outer circumference and the central axis of the spherical surface of 5 μm or less.
And the outer diameter is 0.99 in the insertion portion 21a of the glass thin tube 21.
7 mm ± 0.005 mm and inner diameter 0.68 mm + 0.0
Length 3.45 mm with inner hole 24b of 02 / -0 mm
The glass inner thin tube 24 is inserted and fixed in a state in which the end surface 24a perpendicular to the tube axis of the glass inner thin tube 24 is in contact with the translucent spherical surface 22b of the partial spherical lens 22. An adhesive 23 made of an epoxy-based ultraviolet curable resin for adhering the inner thin tube 24 is provided, and the center axis of the inner hole 21b of the glass thin tube 21, the optical axis of the partial spherical lens 22 and the center of the inner hole 24b of the glass inner thin tube 24. The amount of misalignment with the axis is 3 μm. In addition, the glass thin tube 21
The thin tube 24 in the glass has a thickness of 1 mm and a wavelength of 350 to 5
It is made of transparent borosilicate glass that transmits 85 nm of light of 00 nm.

As shown in FIG. 9, this optical collimator 20 has an end face 25a of the optical fiber 25 with respect to an outer peripheral face 26a.
The optical fiber 25 has an axial deviation of 0.5 μm from the core center of
Is fixed to the inner hole 26b and the outer diameter is 0.68 mm + 0 /-
An end face 2 of the optical fiber 25 is inserted by inserting a capillary tube 26 having a length of 0.002 mm and a total length of 5.25 mm into an inner hole 24b which is an insertion portion of the glass inner capillary tube 24 in the glass capillary tube insertion portion 21a.
5a and the spherical surface 22b of the partial spherical lens 22 are fixed at a position where the distance d2 is 0.182 mm ± 2 μm,
The outgoing light is bent at 0.1 ° within a desired 0.2 °.

When the capillary 26 to which the optical fiber 25 having the inclined end surface 25a is fixed is fixed to the optical collimator 20, the emitted light is offset by 95 μm from the optical axis of the optical fiber 25 as shown in FIG. Will cause
When measuring insertion loss and return loss, set the working distance to 2
A pair of optical collimators 20 set to 0 mm and facing each other
The offset positions of are matched as shown in FIG. 6 (B) or (C). The insertion loss and the return loss were measured.

The results were excellent, not much different from those of the optical collimator 10 described above.

Next, a method of assembling the optical collimator 20 will be described.

First, as shown in FIG. 10 (A), the inner hole 2
1d has an inner diameter of 1.005 mm and a total length of 6.0 mm, and a glass capillary 21 having an outer diameter of 0.997 m shown in FIG. 10 (B).
m ± 0.005mm and inner diameter 0.68mm + 0.002
A glass inner thin tube 24 having a length of 3.45 mm having an inner hole 24 b of − / − 0 mm, and an optical glass LaSF015 having a substantially uniform refractive index shown in FIG. A partially spherical lens having the same light-transmitting spherical surfaces 22b and 22c, a radius of curvature R of 1.250 ± 0.0015 mm, a diameter of φ0.98 mm, and an eccentricity between the central axis of the outer circumference and the central axis of the spherical surface within 5 μm. 22 and an optical fiber 25 shown in FIG. 10 (D) fixed to the inner hole 26b, and a capillary tube 26 having an outer diameter of 0.68 mm + 0 / −0.002 mm and a total length of 5.25 mm is prepared.

Next, the glass thin tube 2 shown in FIG.
As shown in FIG. 11 (B), the inner glass tube 24 is inserted into the inner hole 21d of No. 1 to insert the right end face 24a into the insertion portion 21a.
Is fixed at a position having a length of 2.5 mm, and is fixed with an adhesive 23 made of an epoxy-based ultraviolet curing resin. Next, as shown in FIG. 11C, the partial spherical lens 22 is inserted into the inner hole 21d of the glass thin tube 21 to insert the glass inner thin tube 2
The light transmissive spherical surface 22b is brought into contact with the end surface 24a of No. 4 to position the partial spherical lens 22, and then the glass thin tube 21
The partial spherical lens 12 is fixed to the inner hole 21d of the above with the adhesive 23. Finally, as shown in FIG. 11 (D), the capillary tube 26 in which the optical fiber 25 is fixed to the inner hole 26b is replaced by the glass capillary tube 2
1 The end surface 25a of the optical fiber 25 and the spherical surface 22b of the partial spherical lens 22 are inserted into the inner hole 24b which is the insertion portion of the glass inner thin tube 24 in the insertion portion 21a, and the distance d is 0.182 m.
The optical collimator 20 is obtained by fixing and adhering to a position of m ± 2 μm.

In the above embodiment, the split sleeve and the transparent glass tube are used. However, the present invention is not limited to this, and a plastic tube or a hole for confirming the distance between the end face of the optical fiber and the spherical surface of the partial spherical lens is provided. A metal tube or the like may be used.

The insertion loss of the above optical collimator was measured as follows. That is, two prepared optical collimators are prepared, an optical fiber is connected to a laser diode stabilizing light source having a wavelength of 1550 nm, and one optical collimator is connected to this optical fiber by a fusion splice. This optical collimator is fixed to a 5-axis optical stage having two rotation axes orthogonal to the XYZ spatial axes. Next, the other optical collimator is fixed to the optical mount, and the tip of the optical fiber that is the pigtail of the optical collimator is connected to the power meter. After that, the 5-axis stage is operated to align the two optical collimators so as to form an image-forming relationship, and in that state, the amount of received light is measured by the power meter. The insertion loss was calculated by subtracting the measured value of the received light amount when the stabilized light source and the power meter were directly connected by an optical fiber from the received light amount. The return loss of the optical collimator was measured as follows. That is, OTDR (Optical Time Domain)
An optical fiber having a sufficient length of 10 mm or more is connected to the n Reflect Meter. An optical collimator was fixed to the tip with a fusion splice, and the intensity of the reflected light was measured to measure the return loss.

[0089]

The optical collimator of the present invention has a thin tube and a cylindrical portion made of glass with a substantially uniform refractive index fixed in the inner hole of the thin tube, leaving an insertion portion of a predetermined length, and the centers of curvature are substantially A lens component including a partial spherical lens having the same light-transmitting spherical surface and an adhesive for bonding the partial spherical lens to a thin tube, and an axial deviation amount between the central axis of the thin tube and the optical axis of the partial spherical lens is within 5 μm. And the optical fiber end face of the capillary with the optical fiber fixed in the inner hole when the axial deviation between the outer peripheral surface and the core center of the optical fiber end face in the insertion part of the lens component is within 1.5 μm, the focus position ± of the partial spherical lens. Since it is fixed at a position of 40 μm or less, it is possible to extremely easily manufacture an optical collimator in which the emitted light has a level at which the emitted light bends which could not be realized in the past.

Further, in the optical collimator of the present invention, since the partial spherical lens has a refractive index of 1.7 or more, spherical aberration is reduced, and parallel light having high connection efficiency and outgoing light bending can be obtained.

In the optical collimator of the present invention, since the distance between the end face of the optical fiber and the spherical surface of the partial spherical lens is 0.1 mm or more, the light reflected from the spherical surface of the partial spherical lens and entering the optical fiber is significantly reduced. It becomes possible to use it for constructing a high-speed and large-capacity optical communication system.

In the optical collimator of the present invention, since the thin tube has the penetrating portion at the site where the spherical surface of the partial spherical lens and the position at a predetermined distance can be observed, the end surface of the optical fiber is set to the focal position ± 40 μm of the partial spherical lens. The optical collimator can be fixed at a position within the range, and a high-performance optical collimator can be easily manufactured.

In the optical collimator of the present invention, the thin tube is made of a transparent material capable of externally measuring the distance between the spherical surface of the partial spherical lens and the end surface of the optical fiber. Therefore, the end surface of the optical fiber is within the focal position ± 40 μm of the partial spherical lens. The optical collimator can be easily fixed to the position (1), and a high-performance optical collimator can be easily manufactured.

In the optical collimator of the present invention, since the thin tube is made of glass or crystallized glass, it is possible to use a highly accurate and inexpensive thin tube and reduce the construction cost of a high speed and large capacity optical communication system. Is possible.

In the optical collimator of the present invention, since the thin tube is the split sleeve, the inner diameter of the split sleeve has a relation of fitting and tight fitting with the capillary tube having the optical fiber, and the inner surface of the thin tube and the partial spherical lens are It is possible to eliminate the dimensional difference between the two that affects the deviation from the optical axis, and it is possible to manufacture an optical collimator in which the optical signal passing through the inside is stable.

In the optical collimator of the present invention, since the split sleeve is made of metal, the hardness is low and the surface of the partial spherical lens or the capillary tube with the optical fiber is not damaged, and it is possible to prevent dust generation. With phosphor bronze or the like having good dimensional reproducibility, stable partial spherical lenses and capillaries with optical fibers can be fixed, and an optical collimator with a stable optical signal passing therethrough can be manufactured.

In the optical collimator of the present invention, the adhesive is an epoxy resin or a low-melting glass frit mixed with a filler made of one or more of ceramic, glass or metal, so that the volume shrinkage upon curing the adhesive is achieved. By preventing the positional displacement of the partial spherical lens due to, it is possible to prevent liquid dripping and improve the strength of the adhesive by mixing the filler, and the optical signal that passes through the interior with excellent environmental resistance is stable A collimator can be made.

In the optical collimator of the present invention, an inner thin tube having an inner hole with a predetermined inner diameter is inserted and arranged in the insertion portion of the thin tube, and the end surface perpendicular to the tube axis of the inner thin tube is in contact with the spherical surface of the partially spherical lens. Since the partial spherical lens and the inner thin tube are fixed to the thin tube in the correct position and in the correct coaxial relationship, the optical collimator having excellent optical characteristics can be manufactured.

In the optical collimator of the present invention, the inner thin tube has a thickness of 1
Since it is made of transparent glass that transmits 50% or more of light having a wavelength of 350 to 500 nm in mm, it has a high sensitivity for curing reaction of the photocurable adhesive. By using the agent, the optical fiber or the capillary tube with the optical fiber can be fixed in the inner thin tube in a short time, and the optical collimator can be efficiently manufactured.

The method of assembling the optical collimator according to the present invention is as follows.
An inner thin tube having an inner hole with a predetermined inner diameter is inserted into the inner hole of the thin tube to fix an end face perpendicular to the tube axis of the inner thin tube with a predetermined accuracy at a predetermined position, and a partial spherical surface is formed in the inner hole of the thin tube. The partial spherical lens is positioned by inserting the lens into contact with the end surface of the inner thin tube, and then the partial spherical lens is adhesively fixed inside the thin tube, so positioning of the partial spherical lens relative to the inner hole of the thin tube is accurate. Therefore, it is possible to efficiently manufacture an optical collimator.

Further, according to the method of assembling the optical collimator of the present invention, the inner thin tube is removed before or after the partial spherical lens is bonded and fixed in the thin tube, so that the thin tube inner hole and the partial spherical lens are easily combined. A highly accurate coaxial relationship can be realized, and an optical collimator excellent in optical characteristics can be easily manufactured with good reproducibility, which is an excellent effect in practical use.

[Brief description of drawings]

1A and 1B are explanatory views of the bending of emitted light emitted from an optical collimator of the present invention, FIG. 1A is an explanatory view using the optical collimator of the present invention, and FIG. 1B is an explanatory view of a defective optical collimator.

FIG. 2 is an explanatory diagram of the present invention, in which FIG. 2A is a diagram in which optical collimators using optical collimators are arranged opposite to each other. (B)
Is an explanatory view of the beam waist position when the optical fiber end face is arranged at the focal position of the partial spherical lens, and (C) is an explanation of the beam waist position when the optical fiber end face is arranged in front of the focal position of the partial spherical lens. FIG. 6D is an explanatory diagram of a beam waist position when the optical fiber end face is arranged behind the focal position of the partial spherical lens.

FIG. 3 is a diagram illustrating a relationship between a spherical surface and a radius of curvature of a partial spherical lens, a distance from an end surface of an optical fiber, and reflected light.

FIG. 4 is an explanatory view of an optical collimator of the present invention,
(A) is a plan view and (B) is a sectional view.

FIG. 5 is a cross-sectional explanatory view of a main part of the optical collimator of the present invention.

FIG. 6 is an explanatory diagram of a method of using the optical collimator according to the present invention, in which (A) is a diagram in which an offset position is displaced;
FIG. 6B is a diagram showing the offset positions aligned, and FIG. 6C is a diagram showing the positions of the emitted lights aligned with the offset positions displaced.

FIG. 7 is an explanatory view of each member constituting the optical collimator of the present invention, in which (A) and (B) are split sleeves, (C) is an inner thin tube, (D) is a partial spherical lens, and (E). Is an explanatory view of a capillary tube with an optical fiber.

FIG. 8 is an explanatory diagram for manufacturing the optical collimator of the present invention, in which (A) is an explanatory diagram for mounting the inner thin tube on the split sleeve;
(B) is an explanatory view of mounting the partial spherical lens on the split sleeve, (C) is an explanatory view of removing the inner thin tube from the split sleeve, and (D) is an explanatory view of mounting a capillary tube with an optical fiber on the split sleeve.

FIG. 9 is a sectional view of another optical collimator according to the present invention.

FIG. 10 is an explanatory view of each member constituting another optical collimator of the present invention, where (A) is a glass thin tube, (B) is a glass inner thin tube, (C) is a partially spherical lens, and (D) is Explanatory drawing of the capillary tube with an optical fiber.

11A and 11B are explanatory views for manufacturing the optical collimator of the present invention, where FIG. 11A is an explanatory view of a glass capillary, FIG. 11B is an explanatory view of mounting a glass inner tube on a glass capillary, and FIG. FIG. 3D is an explanatory view of mounting the partial spherical lens on FIG. 3D, and FIG. 6D is an explanatory view of mounting the capillary tube with the optical fiber in the glass inner thin tube.

FIG. 12 is an explanatory diagram of a method of manufacturing a conventional optical collimator.

[Explanation of symbols]

10, 20 Optical collimator 11 Split sleeves 11a, 21a Insertion portions 11d, 14b, 17b, 21b, 21d, 24b, 2
6b Inner hole 12, 22 Partial spherical lens 12a, 22a Columnar part 12b, 12c, 22b, 22c Light transmissive spherical surface 12d Annular groove 13, 23 Adhesive 14, 26 Capillary tube 14a, 26a Outer peripheral surface 15, 25 Optical fiber 15a, 17a, 24a, 25a End face 17 Inner thin tube 21 Glass thin tube 24 Glass inner thin tube L Emitted light (helium-neon laser light) LB Reflected light W Offset R Curvature radius f Focal length BW Beam waist WD Working distance FP Focal position n1 Space refractive index n2 Refractive index n3 of optical fiber Refractive indices d1 and d2 of partial spherical lens Distance between optical fiber end surface and partial spherical lens spherical surface α Angle of inclination with respect to plane perpendicular to optical axis β Optical axis of light emitted from end surface of optical fiber Angle formed by and

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hirokazu Tanaka             2-7 Harumi Arashi, Otsu City, Shiga Prefecture             Air Glass Co., Ltd. (72) Inventor Masaaki Kakumi             2-7 Harumi Arashi, Otsu City, Shiga Prefecture             Air Glass Co., Ltd. F term (reference) 2H037 AA01 BA32 CA10 CA13 DA04                       DA05 DA06 DA15 DA17                 2H043 AA05 AA23 AB02 AB16 AD03                       AE02

Claims (14)

[Claims] 1. A thin tube and a light transmissive spherical surface having substantially the same center of curvature at both ends of a cylindrical portion made of glass having a substantially uniform refractive index and fixed in an inner hole of the thin tube leaving an insertion portion of a predetermined length. A lens component including a partial spherical lens and an adhesive for bonding the partial spherical lens to a thin tube, and an amount of axial misalignment between the central axis of the thin tube and the optical axis of the partial spherical lens is 5 μm or less, and insertion of the lens component. The optical fiber end face of the capillary with the optical fiber fixed in the inner hole is fixed at a position within ± 40 μm of the focal position of the partial spherical lens when the axial deviation between the outer peripheral surface and the core center of the optical fiber end face is within 1.5 μm. Optical collimator characterized by 2. The optical collimator according to claim 1, wherein the partial spherical lens has a refractive index of 1.7 or more. 3. The optical collimator according to claim 1, wherein the distance between the end face of the optical fiber and the spherical surface of the partial spherical lens is 0.1 mm or more. 4. The optical collimator according to claim 1, wherein the material of the thin tube is glass or crystallized glass. 5. The optical collimator according to claim 1, wherein the thin tube is a split sleeve. 6. The optical collimator according to claim 5, wherein the material of the split sleeve is metal. 7. The adhesive is an epoxy resin or a low melting point glass frit mixed with a filler made of at least one of ceramic, glass and metal, and the adhesive is a glass frit having a low melting point. Optical collimator. 8. An inner thin tube having an inner hole of a predetermined inner diameter is inserted and arranged in an inserting portion of the thin tube, and an end face perpendicular to the tube axis of the inner thin tube is brought into contact with the spherical surface of the partial spherical lens. The optical collimator according to claim 1, wherein the optical collimator is adhesively fixed in a state. 9. The distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is smaller than the optimum value calculated by the refractive index and the spherical radius of the partial spherical lens, and within a practically required working distance range. Beam waist position is within ± 5m
The optical collimator according to claim 1, wherein the optical collimator is within m. 10. A thin tube and a light-transmissive spherical surface having substantially the same center of curvature at both ends of a cylindrical portion made of glass having a substantially uniform refractive index, which is fixed to the inner hole of the thin tube leaving an insertion portion of a predetermined length. A lens component including a partial spherical lens and an adhesive for bonding the partial spherical lens to a thin tube, and an amount of axial misalignment between the central axis of the thin tube and the optical axis of the partial spherical lens is 5 μm or less, and insertion of the lens component. At the time of fixing the optical fiber to the optical fiber of the capillary which fixed the optical fiber to the inner hole when the axial deviation amount between the outer peripheral surface and the core center of the optical fiber end surface is within 1.5 μm, the spherical surface of the partial spherical lens and the optical fiber end surface are A method for assembling an optical collimator fixed to a position within a focal position ± 40 μm of a partial spherical lens, wherein the end surface of the optical fiber and the translucent spherical surface of the partial spherical lens are fixed when the capillary tube is fixed to the insertion part of the lens component. Distance between A method for assembling an optical collimator, characterized in that the distance between the capillaries is measured by measuring the distance from the outside. 11. The thin tube has a penetrating portion at a site where a position where the spherical surface of the partial spherical lens and the end face of the optical fiber are at a predetermined distance can be observed, and the partial spherical surface is obtained by using substantially parallel measurement light. The method of assembling the optical collimator according to claim 10, wherein the position is determined by measuring the distance between the spherical surface of the lens and the end face of the optical fiber from the outside. 12. The thin tube is made of a transparent body capable of measuring the distance between the spherical surface of the partial spherical lens and the end surface of the optical fiber from the outside, and the measuring surface is used to measure the spherical surface of the partial spherical lens and the end surface of the optical fiber. 11. The method for assembling the optical collimator according to claim 10, wherein the position is determined by measuring the distance from the outside. 13. The thin tube and / or the inner thin tube has a thickness of 1 m.
The method of assembling the optical collimator according to claim 12, which is made of transparent glass that transmits 50% or more of light having a wavelength of 350 to 500 nm at m. 14. The distance between the spherical surface of the partial spherical lens and the end face of the optical fiber is made smaller than an optimum value calculated by the refractive index of the partial spherical lens and the spherical radius of the light transmitting spherical surface, which is substantially required. 14. The method of assembling the optical collimator according to claim 10, wherein the beam waist position is set within ± 5 mm of a predetermined value within the working distance.