JP3938490B2 - Optical axis correction method of optical module - Google Patents

Description

【００１８】
この光軸修正は、光損失値の増加分が、溶接固定前にフィルタホルダ１５とコリメータ１１の光軸を調整した時点と比較して±0.０１ｄＢ程度になるまで数回繰り返して行う。
この結果、本実施例では、光ファイバ１３ａと光ファイバ１３ｂとの間の光損失に関し、溶接固定前にフィルタホルダ１５とコリメータ１１の光軸を調整したとき、フィルタホルダ１５とコリメータ１１とをＹＡＧレーザで溶接固定後、光軸修正後、のそれぞれにおける光損失は表２のようになった。
【００１９】
【表２】

【００２０】
従って、本発明方法によれば、光部品相互間の光軸調整後に溶接して製造される光モジュールにおける溶接に起因した光軸のずれを、溶接前の光軸調整時の状態まで回復させることができる。
ここで、本発明方法は、前記実施形態の光モジュール１０のみに限定的に適用されるものではなく、図３に示す光モジュール２０にも適用することができる。
【００２１】
光モジュール２０は、図３に示すように、第１の光部品であるホルダ２１と、第２の光部品であるスリーブ２５とを備えている。
ホルダ２１は、図３に示したように、円筒状の部材で、光学フィルタ２２とレンズ２４ａを保持したレンズホルダ２４とをスペーサ２３を介して保持し、スリーブ２５側にテーパ面２１ａが形成されている。
【００２２】
スリーブ２５は、図３に示したように、シングルモードファイバからなる光ファイバ２６ａ，２６ｂを取り付けたフェルール２６を保持し、テーパ面２１ａに当接する湾曲面からなる当接面２５ａが形成されている。
更に、本発明方法は、上記した光モジュール１０，２０の他、湾曲面を有する第１の光部品に、当接面を有する第２の光部品を前記当接面を前記湾曲面に当接させ、前記両光部品の光軸を調整した状態で当接部を溶接固定する光モジュールであれば、種々の光モジュールに適用可能なことは言うまでもない。
【００２３】
【発明の効果】
請求項１乃至７の発明によれば、光部品相互間の光軸調整後に溶接して製造される光モジュールにおける光損失の増加を抑えることが可能な光モジュールの光軸修正方法を提供することができる。
【図面の簡単な説明】
【図１】本発明の光軸修正方法を適用する光モジュールの断面正面図である。
【図２】図１のＡ部拡大図である。
【図３】本発明の光軸修正方法を適用する他の光モジュールの断面正面図である。
【図４】従来の光軸修正方法を説明する光モジュールの断面正面図である。
【符号の説明】
１０ 光モジュール
１１ コリメータ（第１の光部品）
１２ スリーブ
１３ フェルール
１３ａ，１３ｂ 光ファイバ
１４ レンズホルダ
１４ａ レンズ
１４ｂ テーパ面
１５ フィルタホルダ（第２の光部品）
１５ａ 光学フィルタ
１５ｂ 当接面
２０ 光モジュール
２１ ホルダ（第１の光部品）
２１ａ テーパ面
２２ 光学フィルタ
２３ スペーサ
２４ レンズホルダ
２４ａ レンズ
２５ スリーブ（第２の光部品）
２５ａ 当接面
２６ａ，２６ｂ 光ファイバ
２６ フェルール[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for correcting an optical axis of an optical module.
[0002]
[Prior art]
As an optical module, for example, an optical module including at least an optical fiber, a lens, and an optical filter, for example, an optical module 1 having a structure shown in FIG. 4 is known.
The optical module 1 includes a sleeve 2 and a holder 5. The sleeve 2 holds a ferrule 3 to which optical fibers 3a and 3b made of a single mode fiber are attached. The holder 5 holds the optical filter 6 and the lens holder 8 holding the lens 8 a via a spacer 7.
[0003]
When the optical module 1 is manufactured, the sleeve 2 and the holder 5 are brought into contact with each other, the light incident from the optical fiber 3a is reflected by the optical filter 6 and incident on the optical fiber 3b, while the light emitted from the optical fiber 3b is reflected. The optical axes of the sleeve 2 and the holder 5 are optimally adjusted so that the loss is minimized. And the contact part of the sleeve 2 and the holder 5 is welded at 12-15 places equidistantly along the circumferential direction, for example with this YAG laser in this optimal alignment position.
[0004]
In this welding, for example, first, three points at equal intervals along the circumferential direction are welded at the same time, and then the positions are shifted in the circumferential direction and further three points at equal intervals are welded simultaneously. Then, the contact portion between the sleeve 2 and the holder 5 is welded at 12 to 15 equal intervals along the circumferential direction by welding at three points along the circumferential direction two or three times while shifting the position. The optical module 1 is manufactured.
[0005]
[Problems to be solved by the invention]
By the way, when manufacturing an optical module including a sleeve and a holder, if the sleeve and the holder are welded and fixed with a YAG laser, the welding position is caused by the deviation of the laser irradiation position, the output variation, the difference in the state of the welded portion, etc. Depending on the laser, the shrinkage caused by laser irradiation differs. For this reason, in the manufactured optical module, the position of the sleeve and the holder is inclined from the optimum alignment position. As a result, the optical module has a problem that the optical axis is shifted between the sleeve and the holder, and the optical loss between the optical fiber 3a and the optical fiber 3b increases.
[0006]
The present invention has been made in view of the above points, and provides an optical module optical axis correction method capable of suppressing an increase in optical loss of an optical module manufactured by welding after optical axis adjustment between optical components. The purpose is to provide.
[0007]
[Means for Solving the Problems]
To achieve the aforementioned object in the present invention, the first optical component having a curved surface, a second optical component having an abutment surface is brought into contact with the abutment surface on the curved surface, the two light components an optical module contact surface in a state where the optical axis and adjustment of the two optical components by monitoring the optical loss is produced by welding fixing the abutment is in contact with the curved surface between its optical axis An optical axis correction method for correcting the optical axis, wherein an external force is sequentially applied to a plurality of arbitrary locations around the contact portion while monitoring the optical loss between the two optical components, and a location where the optical loss is minimized is searched for. A search step, a release step of releasing the external force when a minimum location is found, and an irradiation step of irradiating a laser beam to the detected minimum location and fixing the location by welding. method of the optical axis correction light module A.
[0008]
Preferably, the first optical component is a collimator in which a lens holder that holds a lens is attached to a holding member that holds a ferrule to which an optical fiber is attached, and the curved surface is formed in the lens holder. To do.
Preferably, the second optical component is a filter holder holding an optical filter.
[0009]
More preferably, the first optical component is a holder that holds an optical filter and a lens holder holding a lens via a spacer. Preferably, the second optical component is a holding member that holds a ferrule to which an optical fiber is attached.
Preferably, a correction cycle including the search step, the release step, and the irradiation step is repeated a plurality of times.
Preferably, the energy of the laser beam irradiated in the irradiation step is determined corresponding to the increase in the optical loss before and after the welding fixation.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the optical module correcting method for an optical module according to the present invention will be described in detail with reference to FIGS.
As shown in FIG. 1, the optical module 10 includes a collimator 11 that is a first optical component and a filter holder 15 that is a second optical component.
[0011]
As shown in FIG. 1, the collimator 11 has a lens holder 14 attached to a sleeve 12. The sleeve 12 holds a ferrule 13 to which optical fibers 13a and 13b made of a single mode fiber are attached. The lens holder 14 is a cylindrical member that holds a lens 14a, and a tapered surface 14b is formed on the filter holder 15 side.
[0012]
The filter holder 15 is a cylindrical member that holds the optical filter 15a, and as shown in FIG. 1, a contact surface 15b that is a curved surface that contacts the tapered surface 14b is formed.
The optical module 10 totally reflects light (wavelength λ1) incident from the optical fiber 13a by the optical filter 15a and emits the light to the optical fiber 13b, and light (wavelength λ2) incident on the filter holder 15 from the left is the optical fiber 13b. Has a function of combining with each other. Further, the optical module 10 totally reflects the light having the wavelength λ1 out of the light incident from the optical fiber 13b (wavelengths λ1, λ2) by the optical filter 15a, emits the light to the optical fiber 13a, and transmits the light having the wavelength λ2. It has a demultiplexing function for emitting light to the left of the filter holder 15.
[0013]
The optical module 10 configured as described above is manufactured as follows. First, the lens holder 14 is fitted to the tip of the sleeve 12, and the collimator 11 is assembled by welding and fixing with a YAG laser.
Next, the filter holder 15 is assembled to the collimator 11 by bringing the contact surface 15 b into contact with the tapered surface 14 b. At this time, while monitoring the light incident from the optical fiber 13a, totally reflected by the optical filter 15a and emitted to the optical fiber 13b, the contact surface 15b is finely moved along the tapered surface 14b, The optical axis of the collimator 11 is adjusted. With the optical axis adjusted, the contact portion where the contact surface 15b is in contact with the tapered surface 14b is welded and fixed with a YAG laser.
[0014]
In this welding, three YAG laser heads are arranged on the outer periphery of the collimator 11 at intervals of 120 degrees, and three locations along the circumferential direction of the contact portion where the contact surface 15b contacts the taper surface 14b are equally spaced. Weld simultaneously from three directions. Thereby, since the impact accompanying welding is equalized, the positional deviation of the contact portion due to the impact is minimized. Then, while the irradiation position is moved along the circumferential direction of the contact portion, the contact portion in which the contact surface 15b is in contact with the tapered surface 14b by irradiating the YAG laser beam 2 to 3 times is 6 to 6 times. Nine locations are welded to manufacture the optical module 10.
[0015]
The optical module 10 manufactured in this way monitors the optical loss between the optical fibers 13a and 13b in the same manner as described above, and uses the optical axis correcting method described below for those whose optical loss is a predetermined value or more. Based on this, optical axis correction is performed.
First, while monitoring the optical loss between the optical fiber 13a and the optical fiber 13b, an external force is applied to any plurality of locations around the contact portion where the contact surface 15b contacts the tapered surface 14b (see the arrow in FIG. 2). Are sequentially applied using, for example, a metal rod. In this manner, a portion where the optical loss to be monitored is minimized is searched for while applying an external force sequentially to an arbitrary plurality of locations.
[0016]
When a location where the optical loss is minimized is found, the external force applied by the metal rod is released, and YAG laser light having an energy corresponding to the increase in the optical loss value before and after welding fixation is irradiated.
The energy of the YAG laser light to be radiated was subjected to an experiment to variously change the energy value of the laser light to be radiated depending on the increase in the optical loss value before and after welding fixation, and the optimum irradiation energy value for correcting the angle deviation was obtained. . The results are shown in Table 1.
[0017]
[Table 1]

[0018]
This optical axis correction is repeated several times until the increase in the optical loss value is about ± 0.01 dB compared to the time when the optical axes of the filter holder 15 and the collimator 11 are adjusted before welding and fixing.
As a result, in this embodiment, regarding the optical loss between the optical fiber 13a and the optical fiber 13b, when the optical axes of the filter holder 15 and the collimator 11 are adjusted before welding and fixing, the filter holder 15 and the collimator 11 are connected to the YAG. Table 2 shows the optical loss after fixing with laser and after correcting the optical axis.
[0019]
[Table 2]

[0020]
Therefore, according to the method of the present invention, the optical axis shift caused by welding in an optical module manufactured by welding after optical axis adjustment between optical components is recovered to the state at the time of optical axis adjustment before welding. Can do.
Here, the method of the present invention is not limited to the optical module 10 of the above embodiment, but can be applied to the optical module 20 shown in FIG.
[0021]
As shown in FIG. 3, the optical module 20 includes a holder 21 that is a first optical component and a sleeve 25 that is a second optical component.
As shown in FIG. 3, the holder 21 is a cylindrical member that holds the optical filter 22 and the lens holder 24 holding the lens 24a via a spacer 23, and a tapered surface 21a is formed on the sleeve 25 side. ing.
[0022]
As shown in FIG. 3, the sleeve 25 holds a ferrule 26 to which optical fibers 26a and 26b made of a single mode fiber are attached, and a contact surface 25a made of a curved surface that makes contact with the tapered surface 21a is formed. .
Further, in the method of the present invention, in addition to the optical modules 10 and 20, the first optical component having a curved surface is brought into contact with the second optical component having a contact surface, and the abutting surface is brought into contact with the curved surface. Needless to say, the optical module can be applied to various optical modules as long as the abutting portion is welded and fixed in a state where the optical axes of the optical components are adjusted.
[0023]
【The invention's effect】
According to invention of Claims 1 thru | or 7 , the optical axis correction method of the optical module which can suppress the increase in the optical loss in the optical module manufactured by welding after the optical axis adjustment between optical components is provided is provided. Can do.
[Brief description of the drawings]
FIG. 1 is a cross-sectional front view of an optical module to which an optical axis correcting method of the present invention is applied.
FIG. 2 is an enlarged view of a portion A in FIG.
FIG. 3 is a cross-sectional front view of another optical module to which the optical axis correcting method of the present invention is applied.
FIG. 4 is a cross-sectional front view of an optical module for explaining a conventional optical axis correcting method.
[Explanation of symbols]
10 Optical module 11 Collimator (first optical component)
12 Sleeve 13 Ferrule 13a, 13b Optical fiber 14 Lens holder 14a Lens 14b Tapered surface 15 Filter holder (second optical component)
15a Optical filter 15b Contact surface 20 Optical module 21 Holder (first optical component)
21a Tapered surface 22 Optical filter 23 Spacer 24 Lens holder 24a Lens 25 Sleeve (second optical component)
25a Contact surface 26a, 26b Optical fiber 26 Ferrule

Claims (7)

The first optical component having a curved surface is brought into contact with the second optical component having a contact surface, and the contact surface is brought into contact with the curved surface, and the optical loss between the two optical components is monitored. An optical axis correction method for correcting an optical axis of an optical module manufactured by welding and fixing a contact portion whose contact surface is in contact with a curved surface in a state where the optical axis of the component is adjusted,
A step of searching for a location where the optical loss is minimized by sequentially applying an external force to any plurality of locations around the contact portion while monitoring the optical loss between the optical components ,
A release step of releasing the external force when a minimum point is found;
A method of correcting an optical axis of an optical module, comprising: an irradiation step of irradiating a laser beam to a minimum spot discovered and fixing the spot by welding .  The first optical component is a collimator in which a lens holder that holds a lens is attached to a holding member that holds a ferrule to which an optical fiber is attached, and the curved surface is formed in the lens holder. Optical module optical axis correction method.  The optical axis correcting method for an optical module according to claim 1, wherein the second optical component is a filter holder holding an optical filter.  2. The optical axis correcting method for an optical module according to claim 1, wherein the first optical component is a holder that holds an optical filter and a lens holder that holds a lens via a spacer.  2. The optical axis correcting method for an optical module according to claim 1, wherein the second optical component is a holding member that holds a ferrule to which an optical fiber is attached. The method of correcting an optical axis of an optical module according to claim 1, wherein a correction cycle including the searching step, the releasing step, and the irradiation step is repeated a plurality of times. 2. The method of correcting an optical axis of an optical module according to claim 1, wherein the energy of the laser beam irradiated in the irradiation step is determined in accordance with an increase in the optical loss before and after the welding fixing.

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