JP2014048577A - Optical fiber joint method, and optical fiber joint device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber joint method capable of aligning and joining an optical circuit such as a PLC and the like and a ferrule highly accurately.SOLUTION: A problem is solved by an optical fiber joint method including the steps of: imaging a junction surface of a ferrule joined to an end surface of an optical fiber and a junction surface of an optical circuit which is joined with the joint surface of the ferrule: bringing the junction surface of the ferrule into contact with the junction surface of the optical circuit; adjusting a position of the ferrule or the optical circuit based on an adhesion region in which light generated in the junction surface of the ferrule is not detected by bringing the junction surface of the ferrule into contact with the junction surface of the optical circuit; and joining the ferrule and the optical circuit after the adjusting step.

Description

  The present invention relates to an optical fiber bonding method and an optical fiber bonding apparatus.

  In general, in an optical module, an optical fiber is bonded to an optical transmission / reception unit in an optical device, and light is transmitted / received between the optical reception / transmission unit and the optical fiber in the optical device. Therefore, when manufacturing the optical module, the optical fiber is bonded to the light receiving / transmitting unit in the optical device. Specifically, a ferrule is bonded to the end face of the optical fiber so as to be easily bonded to the optical device. For example, the ferrule is bonded to a PLC (Planar lightwave circuit) that is an optical device. As a result, the optical device and the optical fiber are joined.

  The positional relationship between the PLC and the ferrule that are joined in this way has a great influence on the light coupling efficiency, and therefore it is necessary to perform precise positioning and joining. Specifically, for example, as a method of joining a ferrule to a PLC, the position (posture etc.) of the ferrule or the like is adjusted while monitoring the light coupling state while the optical device is functioning, and the light coupling efficiency is improved. There is a method of fixing and joining after adjusting to the maximum position. However, this method requires a power source for functioning the optical device, a measuring device for monitoring input / output of light, etc., and the process of joining the optical fibers becomes large, and also requires time. The manufactured optical module is expensive.

  For this reason, there is a method in which the external shape of the PLC and the ferrule is imaged using an imaging device such as a CCD (Charge Coupled Device) camera, the position of the ferrule is adjusted based on the captured image, and is fixedly joined. .

JP 2003-248143 A

  By the way, in the method of imaging the outer shape of the PLC and the ferrule with an imaging device such as a CCD camera and adjusting the position of the ferrule, etc., the image must be picked up from the side surface of the joint portion, etc. It is difficult to apply to modules. In addition, with the miniaturization of the optical module, it is required to align the PLC and the ferrule with higher accuracy, and a method for performing alignment by imaging the external shape of the PLC and the ferrule with an imaging device. There was a limit in terms of accuracy.

The joining of the PLC 10 and the ferrule 20 will be described with reference to FIG. When joining the joining surface 11 of the PLC 10 and the joining surface 21 of the ferrule 20, it is preferable that the joining surface 11 of the PLC 10 and the joining surface 21 of the ferrule 20 are joined so as to completely coincide with each other. However, in practice, it is difficult to join the joining surface 11 of the PLC 10 and the joining surface 21 of the ferrule 20 so as to completely coincide with each other, and as shown in FIG. A misalignment angle φ or the like is generated between the first and second joint surfaces 21. As described above, when the deviation angle φ is generated between the bonding surface 11 and the bonding surface 21, a gap g ₁ is generated between the bonding surface 21 and the bonding surface 11 on the upper surface 22 side of the ferrule 20. On the bottom surface 23 side of 20, a gap g ₂ is generated between the joint surface 21 and the joint surface 11. The gap g ₁ and the gap g ₂ generated in this way have a relationship expressed by Equation 1 when the width of the joint surface 21 in the ferrule 20 is D.

Here, of about 1.5mm width D of the joining surface 21 of the ferrule 20, the deviation angle φ is attempting to align so as to be 0.1 ° or less, the difference between _{g 2} of the gap _{g 1} and the gap _{g 2} It is required to perform alignment so that −g ₁ is 2.6 μm or less. However, it is extremely difficult to perform such fine alignment with the above-described method of capturing the external shape of the PLC and ferrule with the imaging device and performing alignment based on the captured image. High alignment cannot be performed.

  Therefore, there is a need for an optical fiber joining method that can align and join an optical circuit such as a PLC and a ferrule with high accuracy.

  According to one aspect of the present embodiment, an imaging process for imaging the joint surface of the ferrule joined to the end face of the optical fiber and the joint surface of the optical circuit joined to the joint surface of the ferrule, and the ferrule A contact step of bringing the bonding surface of the optical circuit into contact with the bonding surface of the optical circuit, and contacting the bonding surface of the ferrule with the bonding surface of the optical circuit to detect light generated on the bonding surface of the ferrule. An adjustment step of adjusting the position of the ferrule or the optical circuit based on a close contact area, and a bonding step of bonding the ferrule and the optical circuit after the adjustment step. .

  Further, according to another aspect of the present embodiment, a hand in which a ferrule joined to an end face of an optical fiber is installed, and an optical circuit having a joined surface joined to the joint surface of the ferrule is installed. A stage, a position where the light totally reflected on the joint surface of the ferrule is detected, an imaging unit that images the joint surface of the ferrule and the joint surface of the optical circuit, and the joint surface of the ferrule And a light source that irradiates light to the joint surface of the optical circuit, and the imaging unit that is generated on the joint surface of the ferrule when the joint surface of the ferrule and the joint surface of the optical circuit are brought into contact with each other A contact region where no light is detected is detected, adjustment based on the contact region is performed, and the ferrule and the optical circuit are joined.

  According to the disclosed optical fiber bonding method and optical fiber bonding apparatus, an optical circuit such as a PLC and a ferrule can be aligned and bonded with high accuracy.

Explanatory drawing of deviation angle φ between ferrule joint surface and PLC joint surface Structure diagram of optical fiber bonding apparatus in this embodiment Structure diagram of main part of optical fiber bonding apparatus according to the present embodiment Explanatory drawing of ferrule bonded to end face of optical fiber Block diagram of the control part of the optical fiber bonding apparatus in the present embodiment Explanatory drawing of the contact state of the joint surface of a ferrule and the joint surface of PLC Explanatory drawing of scattered light in ferrule (1) Illustration of scattered light in ferrule (2) Explanatory drawing of the ferrule and PLC observed by an imaging part in this Embodiment Flowchart of optical fiber bonding method in the present embodiment Explanatory drawing (1) of the joining method of the optical fiber in this Embodiment Explanatory drawing (2) of the joining method of the optical fiber in this Embodiment Explanatory drawing (3) of the joining method of the optical fiber in this Embodiment Explanatory drawing (4) of the joining method of the optical fiber in this Embodiment Explanatory drawing (5) of the joining method of the optical fiber in this Embodiment Explanatory drawing of the joining method of the optical fiber in this Embodiment (6) Explanatory drawing of the joining method of the optical fiber in this Embodiment (7) Explanatory drawing of the relationship between the emission angle α and the gap g

  Modes for carrying out the invention will be described below. In addition, about the same member etc., the same code | symbol is attached | subjected and description is abbreviate | omitted.

(Optical fiber bonding equipment)
An optical fiber bonding apparatus according to the present embodiment will be described with reference to FIGS. FIG. 2 is a structural diagram of an optical fiber bonding apparatus according to the present embodiment, and FIG. 3 is a principal structural diagram of the optical fiber bonding apparatus according to the present embodiment.

  The optical fiber bonding apparatus in the present embodiment includes a stage 110, a hand 120, a light source 130, and an imaging unit 140. The optical fiber joining apparatus in the present embodiment joins a ferrule 20 joined to an end face of an optical fiber 50 as shown in FIG. 4 and a PLC 10 that is an optical circuit. The PLC 10 is an optical device. Is housed in the housing 30 of the apparatus. It is assumed that the ferrule 20 is bonded to the end face of the optical fiber 50 in advance.

  The stage 110 is provided with a housing 30 in which the PLC 10 is housed. The stage 110 has, for example, six degrees of freedom so that the posture of the PLC 10 can be freely moved. The hand 120 has a gripping part for installing and fixing the ferrule 20 and a position adjusting part that can adjust the position of the ferrule 20, for example, in one axis. Further, contact between the PLC 10 and the ferrule 20 is achieved. A force sensor 121 is provided so that it can be detected. In the present embodiment, the relative positions of the PLC 10 and the ferrule 20 may be adjusted by the stage 110 or the hand 120.

  The light source 130 is provided above the stage 110 and irradiates the joint portion between the PLC 10 and the ferrule 20. The light source 130 is formed by, for example, an LED (Light Emitting Diode) spotlight or the like, and the light emitted from the light source 130 is preferably light having a wavelength with high reflectivity inside the housing 30. For example, when gold plating or the like is applied to the inside of the housing 30, red light having a high reflectance n with respect to gold, for example, an LED spotlight that emits light having a wavelength of about 650 nm is used as the light source 130. It is preferable to use it.

  The imaging unit 140 includes an imaging camera 141, an imaging lens 142, a polarizing plate 143, a color filter 144, and the like. The imaging unit 140 is installed at a position where light totally reflected on the joint surface 21 of the ferrule 20 enters. Therefore, the light totally reflected on the joint surface 21 of the ferrule 20 enters the imaging camera 141 through the color filter 144, the polarizing plate 143, and the imaging lens 142. Thereby, the image in the joint surface 21 with the ferrule 20 can be taken.

  Further, as shown in FIG. 5, the operation and the like of the optical fiber bonding apparatus in the present embodiment are controlled by a control unit 150 such as a computer. Specifically, the position of the stage 110 is controlled through the stage controller / driver 115 under the control of the control unit 150. Further, the position of the hand 120 is controlled via the hand controller / driver 125 under the control of the control unit 150. Information detected by the force sensor 121 is transmitted to the control unit 150 via the sensor amplifier 126. An image captured by the imaging unit 140 is transmitted to the control unit 150 via the grabber 145. Note that the grabber 145 may be provided in the control unit 150.

(Optical fiber bonding method)
Next, an optical fiber bonding method in the present embodiment will be described.

  Initially, joining of PLC10 and the ferrule 20 is demonstrated based on FIG. As described above, it is ideal that the PLC 10 and the ferrule 20 are bonded in a state where the bonding surface 11 of the PLC 10 and the bonding surface 21 of the ferrule 20 coincide with each other, as shown in FIG. . However, in practice, as shown in FIG. 6B, even when the joint surface 11 and the joint surface 21 are substantially parallel, there is a gap, or as shown in FIG. The joint surface 11 and the joint surface 21 may contact in the state which is not parallel. In these cases, the light coupling efficiency decreases, which is not preferable.

  By the way, the light emitted from the light source 130 is reflected inside the housing 30 to become scattered light, and enters the joint surface 21 of the ferrule 20. Here, when the incident angle of the light incident on the joint surface 21 of the ferrule 20 is equal to or larger than the critical angle with respect to the normal line of the joint surface 21, total reflection is performed on the joint surface 21. In the present embodiment, the imaging unit 140 is installed at a position where the light totally reflected on the joint surface 21 of the ferrule 20 is refracted and incident on the upper surface 22 of the ferrule 20.

  Specifically, as shown in FIG. 7, when scattered light reflected inside the housing 30 is incident on the joint surface 21 of the ferrule 20 at an incident angle γ, the incident angle γ should be greater than or equal to the critical angle. For example, the joint surface 21 of the ferrule 20 is totally reflected at a reflection angle γ that is the same angle as the incident angle γ. The light totally reflected at the joint surface 21 of the ferrule 20 enters the upper surface 22 of the ferrule 20 at an incident angle β, is refracted at the upper surface 22 of the ferrule 20, and exits at an output angle α. In the present embodiment, the imaging unit 140 is installed at a position where light emitted from the upper surface 22 of the ferrule 20 at an emission angle α is incident. In the present embodiment, the incident angle, the reflection angle, and the outgoing angle mean angles with respect to the normal lines of the respective surfaces.

Here, when the refractive index of the material forming the ferrule 20 is n ₁ and the refractive index of air is n ₂ , the formula shown in Equation 2 is derived from Snell's law. The equation shown in 3 is derived. For example, when the ferrule 20 is made of glass, n ₁ is about 1.5, n ₂ is about 1.0, and the critical angle is about 42 °. Therefore, light incident on the joint surface 21 of the ferrule 20 at an incident angle γ is totally reflected on the joint surface 21 of the ferrule 20 when γ> 42 °.

  Further, if the inclination angle of the ferrule 20 at the joint surface 21 is the inclination angle δ, β, γ, and δ are in the relationship of the equation shown in Equation 4. The inclination angle δ is an angle with respect to the vertical end surface of the ferrule 20.

The light incident at the incident angle γ on the joint surface 21 of the ferrule 20 is scattered light that is incident at the incident angle ζ on the bottom surface 23 of the ferrule 20, and is light that is refracted at the bottom surface 23 of the ferrule 20 and has an emission angle ε. is there. Therefore, the incident angle γ and the incident angle ζ are related to the formula shown in Formula 5, and the formula shown in Formula 6 is derived from Snell's law on the bottom surface 23 of the ferrule 20. In order for the scattered light to be incident at the incident angle ζ on the bottom surface 23 of the ferrule 20, the exit angle ε is required to be equal to or less than the critical angle. That is, the exit angle ε is required to be an expression shown in Equation 7.

  The state shown in FIG. 7 described above indicates a state where the joint surface 21 of the ferrule 20 and the joint surface 11 of the PLC 10 are not in contact. However, as shown in FIG. 8, when the joint surface 21 of the ferrule 20 and the joint surface 11 of the PLC 10 are in contact with each other, the light is joined in the vicinity of the contact portion between the joint surface 21 and the joint surface 11. 21 is incident on the PLC 20 without being totally reflected. For this reason, since light does not enter the imaging unit 140 from the vicinity of the contact portion, the image captured by the imaging unit 140 appears black. Based on this black reflected area, the joint surface 21 of the ferrule 20 and the PLC 10 It is possible to know the contact portion and contact state with the joint surface 11. In the present embodiment, this black area is referred to as a close contact area. Further, this close contact region does not mean that the bonding surface 11 and the bonding surface 21 are in contact with each other in this region.

  FIG. 9 shows a state of an image on the joint surface 21 of the ferrule 20 captured by the imaging unit 140 in a state where the joint surface 21 of the ferrule 20 and the joint surface 11 of the PLC 10 are not in contact with each other. In FIG. 9, the bonding surface 11 of the PLC 10 and the bonding surface 21 of the ferrule 20 are separated from each other by a gap g. In the present embodiment, the brightness state of the bonding surface 21 of the ferrule 20, that is, a contact area described later. The contact state can be determined according to the state.

(Procedure of optical fiber bonding method)
Next, a procedure of a specific optical fiber joining method will be described with reference to FIG.

  First, in step 102 (S102), the ferrule 20 is joined to the end of the optical fiber 50 as shown in FIG.

  Next, in step 104 (S104), after the ferrule 20 is brought close to the PLC 10, the joint surface 21 of the ferrule 20 and the joint surface 11 of the PLC 10 are observed by the imaging unit 140. Specifically, the PLC 10 is installed on the stage 110, the ferrule 20 is installed on the hand 120, and light is irradiated from the light source 130, the ferrule 20 and the PLC 10 are brought close to each other, and the joining surface 21 of the ferrule 20 and the PLC 10 are joined. The surface 11 is observed by the imaging unit 140. At this time, a gap g is observed between the joint surface 21 of the ferrule 20 and the joint surface 11 of the PLC 10. In this case, as shown in FIG. 11, when the width of the gap g between the ferrule 20 and the PLC 10 is not uniform, the joint surface 21 of the ferrule 20 is inclined with respect to the joint surface 11 of the PLC 10. Is rotated in the direction indicated by the arrow 11A. Thereby, as shown in FIG. 12, it can adjust so that the width | variety of the gap g of the ferrule 20 and PLC10 may become fixed. 11A is a top view, FIG. 11B is a side view, and FIG. 11C is a diagram showing an image of this state captured by the imaging unit 140. . 12A is a top view, FIG. 12B is a side view, and FIG. 12C is a diagram illustrating a state of an image obtained by imaging the state by the imaging unit 140. .

  Next, in step 106 (S106), the joint surface 21 of the ferrule 20 and the joint surface 11 of the PLC 10 are brought into contact with each other. Specifically, the ferrule 20 and the PLC 10 are brought into contact with each other by moving the ferrule 20 in the direction indicated by the arrow 12A in FIG. Whether or not the ferrule 20 and the PLC 10 are in contact with each other can be detected by the force sensor 121 attached to the hand 120. As a result, a close contact region is formed on the joint surface 21 of the ferrule 20. Specifically, when the ferrule 20 and the PLC 10 are brought into contact with each other, a contact area 60a as shown in FIG. 13C is formed on the joint surface 21 of the ferrule 20 imaged in the imaging unit 140, for example. Observed. The contact region 60a is a region where light is not totally reflected on the joint surface 21 of the ferrule 20, and light from the contact region 60a is not incident on the imaging unit 140, and thus is confirmed to be black. In addition, when the contact | adherence area | region does not arise in the joint surface 21, the case where the shift | offset | difference angle (phi) of the joint surface 21 of the ferrule 20 and the joint surface 11 of PLC10 is large is considered. In this case, the ferrule 20 is moved away from the PLC 10, and the position and angle of the ferrule 20 are adjusted by the hand 120 or the like so that the deviation angle φ is equal to or smaller than a predetermined angle, for example, the deviation angle φ is equal to or smaller than 1.1 °. Change and adjust.

  Next, in step 108 (S108), it is determined whether or not the length and width of the contact area are equal to or greater than a predetermined length and width. If one or both of the length and width of the contact area observed in the imaging unit 140 is less than the predetermined length and width, the process proceeds to step 110. On the other hand, if both the length and width of the close contact region observed in the imaging unit 140 are equal to or greater than the predetermined length and width, the process proceeds to step 112. Note that the predetermined length and width vary depending on the position of the imaging unit 140 and the like, and thus cannot be generally described, but are preferably 10 μm or more, and more preferably 30 μm or more.

  Specifically, as shown in FIGS. 13A and 13B, when the joining surface 21 of the ferrule 20 and the joining surface 11 of the PLC 10 are in an ideal state, As shown in FIG. 13 (c), the close contact region 60 a is observed in a wide region of the bonding surface 21. The length L of the close contact region 60a observed at this time is not less than a predetermined length, and the width W is not less than a predetermined width. In this case, the process proceeds to step 112.

  Further, as shown in FIGS. 14A and 14B, when the ferrule 20 is in contact with the joint surface 11 of the PLC 10 on the upper side of the joint surface 21, it is shown in FIG. 14C. As shown, the contact area 60 b is observed on the upper side of the bonding surface 21. In the close contact region 60b observed at this time, the length L of the close contact region 60b is not less than a predetermined length, but the width W is less than the predetermined width. In this case, the process proceeds to step 110.

  Further, as shown in FIGS. 15A and 15B, in the case where the lower surface of the ferrule 20 is in contact with the joint surface 11 of the PLC 10, as shown in FIG. As shown, a close contact region 60 c is observed below the bonding surface 21. In the adhesion region 60c observed at this time, the length L of the adhesion region 60c is not less than a predetermined length, but the width W is less than the predetermined width. In this case, the process proceeds to step 110.

  Further, as shown in FIGS. 16A and 16B, the left side of the joint surface 21 of the ferrule 20 is in contact with the joint surface 11 of the PLC 10, as shown in FIG. 16C. As shown, the contact region 60 d is observed on the left side of the bonding surface 21. In the close contact region 60d observed at this time, the length L of the close contact region 60d is less than a predetermined length, and the width W is not less than the predetermined width. In this case, the process proceeds to step 110.

  Further, as shown in FIGS. 17A and 17B, when the right side of the joint surface 21 of the ferrule 20 is in contact with the joint surface 11 of the PLC 10, it is shown in FIG. 17C. As shown, the contact area 60 e is observed on the right side of the bonding surface 21. In the close contact region 60e observed at this time, the length L of the close contact region 60e is less than a predetermined length, and the width W is not less than the predetermined width. In this case, the process proceeds to step 110.

  Next, in step 110 (S110), the ferrule 20 is moved away from the PLC 10, and the position and inclination of the ferrule 20 are adjusted by the hand 120.

  Specifically, as shown in FIG. 14 (c), when the close contact region 60b is observed above the joining surface 21, the ferrule 20 is moved away from the PLC 10, and the tip of the ferrule 20 is moved up and adjusted. To do.

  Further, as shown in FIG. 15C, when the close contact region 60 c is observed below the joint surface 21, the ferrule 20 is moved away from the PLC 10 and moved and adjusted so that the tip of the ferrule 20 is lowered.

  Further, as shown in FIG. 16C, when the contact area 60d is observed on the left side of the joint surface 21, the ferrule 20 is separated from the PLC 10, and the right side of the tip of the ferrule 20 comes out and the left side retracts. Move to adjust.

  Further, as shown in FIG. 17C, when the close contact region 60 e is observed on the right side of the joint surface 21, the ferrule 20 is separated from the PLC 10 so that the left side of the tip of the ferrule 20 comes out and the right side retracts. Move to adjust.

  After making these adjustments, the process proceeds to step 106 again. That is, the joint surface 21 of the ferrule 20 and the joint surface 11 of the PLC 10 are brought into contact again.

  If the contact area is detected in a state where FIG. 14 (c) or FIG. 15 (c) is combined with FIG. 16 (c) or FIG. 17 (c), it corresponds to each state. Then, the position of the ferrule 20 is adjusted by moving it.

  In the above description, the case where adjustment is performed by moving the position and inclination of the ferrule 20 has been described. However, adjustment may be performed by moving the position and inclination of the PLC 10 by the stage 110.

  Next, in step 112 (S112), the ferrule 20 and the PLC 10 are joined. Thereby, the connection method of the optical fiber in this Embodiment is complete | finished. At this time, after recording each position and the like in the state shown in FIG. 13C, the ferrule 20 is separated from the PLC 10, and the ferrule 20 and the PLC 10 are moved again and brought into contact with the recorded positions. It may be joined later.

  In the above description, the case where the position and the like of the ferrule 20 are adjusted so that the length and width of the contact region 60a and the like are equal to or greater than the predetermined length and width has been described. The position or the like of the ferrule 20 may be adjusted so that becomes the largest. Further, in this adjustment, the position or the like of the ferrule 20 is adjusted to a predetermined length so that the length or width of the contact region 60a or the like becomes longer after the adjustment than before the adjustment. And it may be repeated until it becomes more than the width. When performing these adjustments, these adjustment processes are performed in place of Step 108 and Step 110 described above.

(Close contact area)
By the way, in the imaging unit 140, the adhesion region 60 a and the like that are observed in black are not limited to the portion where the joint surface 11 of the PLC 10 and the joint surface 21 of the ferrule 20 are in contact with each other. It also occurs when 20 joint surfaces 21 are close to each other. That is, when the gap g between the joining surface 11 of the PLC 10 and the joining surface 21 of the ferrule 20 is equal to or less than the penetration depth of the evanescent wave, the adhesion region 60a and the like are observed. Specifically, in the region where the gap g satisfies the equation shown in Equation 8, the penetration of the evanescent wave occurs, and the light is not totally reflected. Therefore, in the image captured by the imaging unit 140, this region is Observed black.

Here, λ is a wavelength in the light source 130, and when 650 nm, n ₁ is 1.5, n ₂ is 1.0, and γ is 55.9 °, the gap g is 141 nm or less. A shift angle φ between the bonding surface 21 of the bonding surface 11 and the ferrule 20 of the PLC10 shown in FIG. 1, than the gap g, the width _{W P} of such contact region 60a at the junction surface 21, formula given in Equation 9 It becomes.

Here, the deviation angle phi 0.1 °, when the g and 141 nm, the width _{W P} of such contact region 60a at the junction plane 21 is approximately 81μm. Incidentally, the width W _P of such contact region 60a at the junction plane 21 is approximately 81Myuemu, the position of the imaging unit 140 is installed, the observation width W such as contact regions 60a to be observed by the imaging unit 140 with different widths Is done. Therefore, the width W of the contact region 60a and the like can be widely observed by selecting the emission angle α and installing the imaging unit 140. Therefore, in the present embodiment, the incident angle γ of the scattered light incident on the joint surface 21 of the ferrule 20 is an angle at which the critical angle is equal to or greater than the critical angle, and at a position where the width W of the contact region 60a can be widely observed. The imaging unit 140 is preferably installed. Note that the length L of the contact area 60a and the like does not need to consider the position where the imaging unit 140 is installed, and the length of the contact area 60a is the same as the actually observed length.

  FIG. 18 shows the relationship between the scattered light exit angle α, the incident angle β, the incident angle γ, and the gap g. It is assumed that the inclination angle δ is 6.0 ° and the critical angle at the joint surface 21 of the ferrule 20 is 41.8 °. In addition, the width W of the close contact region is a value calculated based on the equations shown in Equations 2 to 5.

As shown in FIG. 18A, when the imaging unit 140 is installed at a position where the emission angle α is 70.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 45.2 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 38.8 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, the region where the gap g is about 283 nm or less becomes the adhesion region. Width _{W P} of the joint surface 21 of the contact area is approximately 162μm, the width W of the contact area observed by the image pickup unit 140 is approximately 50 [mu] m.

As shown in FIG. 18B, when the imaging unit 140 is installed at a position where the emission angle α is 65.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 46.8 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 is incident on the upper surface 22 of the ferrule 20 at an incident angle β of 37.2 °, is refracted at the upper surface 22 of the ferrule 20, and is incident on the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 233 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is approximately 134μm, the width W of the contact area observed by the image pickup unit 140 is approximately 48 [mu] m.

As shown in FIG. 18C, when the imaging unit 140 is installed at a position where the emission angle α is 60.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 48.7 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 35.3 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 199 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 114 micrometers, the width W of the contact area observed by the image pickup unit 140 is approximately 46 [mu] m.

As shown in FIG. 18D, when the imaging unit 140 is installed at a position where the emission angle α is 55.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 50.9 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 is incident on the upper surface 22 of the ferrule 20 at an incident angle β of 33.1 °, is refracted at the upper surface 22 of the ferrule 20, and is incident on the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 174 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 99 .mu.m, the width W of the contact area observed by the image pickup section 140 is about 43 .mu.m.

As shown in FIG. 18E, when the imaging unit 140 is installed at a position where the emission angle α is 50.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 53.3 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 is incident on the upper surface 22 of the ferrule 20 at an incident angle β of 30.7 °, is refracted at the upper surface 22 of the ferrule 20, and is incident on the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 155 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 89μm, the width W of the contact area observed by the image pickup unit 140 is approximately 40 [mu] m.

As shown in FIG. 18 (f), when the imaging unit 140 is installed at a position where the emission angle α is 45.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 55.9 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 28.1 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 141 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 81μm, the width W of the contact area observed by the image pickup section 140 is about 36 .mu.m.

As shown in FIG. 18G, when the imaging unit 140 is installed at a position where the emission angle α is 40.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 58.6 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 is incident on the upper surface 22 of the ferrule 20 at an incident angle β of 25.4 °, is refracted at the upper surface 22 of the ferrule 20, and is incident on the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 129 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 74 .mu.m, the width W of the contact area observed by the image pickup section 140 is about 33 .mu.m.

As shown in FIG. 18H, when the imaging unit 140 is installed at a position where the emission angle α is 35.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 61.5 ° Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 is incident on the upper surface 22 of the ferrule 20 at an incident angle β of 22.5 °, is refracted at the upper surface 22 of the ferrule 20, and is incident on the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 120 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 69 .mu.m, the width W of the contact area observed by the image pickup section 140 is about 29 .mu.m.

As shown in FIG. 18 (i), when the imaging unit 140 is installed at a position where the emission angle α is 30.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 64.5 ° Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 19.5 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 113 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 65 .mu.m, the width W of the contact area observed by the image pickup section 140 is about 26 .mu.m.

As shown in FIG. 18J, when the imaging unit 140 is installed at a position where the emission angle α is 25.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 67.6 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 16.4 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 108 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 62 .mu.m, the width W of the contact area observed by the image pickup section 140 is about 22 .mu.m.

As shown in FIG. 18 (k), when the imaging unit 140 is installed at a position where the emission angle α is 20.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 70.8 ° Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 13.2 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 103 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 59 .mu.m, the width W of the contact area observed by the image pickup section 140 is about 19 .mu.m.

As shown in FIG. 18L, when the imaging unit 140 is installed at a position where the emission angle α is 15.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 74.1 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 9.9 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 100 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 57 .mu.m, the width W in the contact area observed by the image pickup unit 140 is approximately 15 [mu] m.

As shown in FIG. 18 (m), when the imaging unit 140 is installed at a position where the emission angle α is 10.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 77.4 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 6.6 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 97 nm or less is an adhesion region. Width _{W P} of the joint surface 21 of the contact area is about 55 .mu.m, the width W of the contact area observed by the image pickup unit 140 is approximately 12 [mu] m.

As shown in FIG. 18 (n), when the imaging unit 140 is installed at a position where the emission angle α is 5.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 80.7 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 3.3 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 95 nm or less is an adhesion region. Width W _P of the joint surface 21 of the contact area is about 54 .mu.m, the width W of the contact area observed by the image pickup unit 140 is about 9 .mu.m.

As shown in FIG. 18 (o), when the imaging unit 140 is installed at a position where the emission angle α is 0.0 °, the light incident on the joint surface 21 of the ferrule 20 at an incident angle γ of 84.0 °. Is totally reflected at the joint surface 21 of the ferrule 20. The light totally reflected at the joint surface 21 enters the upper surface 22 of the ferrule 20 at an incident angle β of 0.0 °, is refracted at the upper surface 22 of the ferrule 20, and enters the imaging unit 140. In this case, when the misalignment angle φ is 0.1 °, a region where the gap g is about 93 nm or less is an adhesion region. Width W _P of the joint surface 21 of the contact area is about 54 .mu.m, the width W of the contact area observed by the image pickup section 140 is approximately 6 [mu] m.

  As shown in FIG. 18, even if the imaging unit 140 is installed at a position with an emission angle of 50 ° or more, the incident of scattered light reflected inside the housing 30 cannot be expected. Therefore, it is preferable that the imaging unit 140 is installed at a position where the emission angle α is 45 ° or less, and since the longer the width W of the close contact region is easier to observe, the larger the emission angle α is preferable. Therefore, it is preferable that the emission angle α is installed at a position around 45 °.

Incidentally, if the value of the deviation angle φ is large, the width W _p of the contact region is narrowed, it may not be possible to observe the imaging unit 140. For example, in the imaging unit 140, assuming that the contact area can be detected if the width W _p of the contact area is 10 μm or more, the emission angle α is 45 °, that is, the incident angle and the reflection angle γ at the bonding surface 21. Is about 55.9 °, the contact area can be detected from the equations shown in Equations 8 and 9 if the deviation angle φ is 0.8 ° or less. Accordingly, when the imaging unit 140 cannot detect the contact area, the contact area can be detected by performing adjustment while moving the position of the ferrule 20. Further, the ferrule 20 and the PLC 10 may be aligned in advance so that the deviation angle φ is 0.8 ° or less in the initial state.

  Further, when a plurality of contact areas are observed due to the surface accuracy of the bonding surface 11 of the PLC 10 or the bonding surface 21 of the ferrule 20, these may be collectively treated as one contact area.

  Although the embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes can be made within the scope described in the claims.

In addition to the above description, the following additional notes are disclosed.
(Appendix 1)
An imaging step of imaging the joint surface of the ferrule joined to the end face of the optical fiber and the joint surface of the optical circuit joined to the joint surface of the ferrule;
A contact step of bringing the joint surface of the ferrule into contact with the joint surface of the optical circuit;
The position of the ferrule or the optical circuit is adjusted based on a contact area where light generated on the joint surface of the ferrule is not detected by bringing the joint surface of the ferrule and the joint surface of the optical circuit into contact with each other. Adjustment process;
After the adjustment step, a joining step for joining the ferrule and the optical circuit;
An optical fiber bonding method comprising:
(Appendix 2)
The optical fiber joining method according to appendix 1, wherein the adjustment step is performed such that both the length value and the width value in the contact region are equal to or greater than a predetermined value.
(Appendix 3)
The optical fiber joining method according to appendix 1, wherein the adjustment step is performed such that a length or a width in the contact region is longer than that before the adjustment.
(Appendix 4)
2. The optical fiber bonding method according to appendix 1, wherein the adjustment step is performed such that the length or width in the adhesion region is maximized.
(Appendix 5)
The optical fiber joining according to any one of appendices 1 to 4, wherein the imaging step is performed by an imaging unit installed at a position where light totally reflected on the joint surface of the ferrule enters. Method.
(Appendix 6)
The optical fiber joining method according to any one of appendices 1 to 5, wherein the ferrule joining surface is irradiated with red light.
(Appendix 7)
A hand on which a ferrule bonded to the end face of the optical fiber is installed;
A stage on which an optical circuit having a bonding surface to be bonded to the bonding surface of the ferrule is installed;
An imaging unit that is installed at a position where the totally reflected light is detected on the joint surface of the ferrule, and that images the joint surface of the ferrule and the joint surface of the optical circuit;
A light source for irradiating light to the joint surface of the ferrule and the joint surface of the optical circuit;
Have
When the joint surface of the ferrule and the joint surface of the optical circuit are brought into contact with each other, a contact region where light is not detected in the imaging unit, which is generated on the joint surface of the ferrule, is detected, and adjustment based on the contact region is performed. An optical fiber bonding apparatus for bonding the ferrule and the optical circuit.
(Appendix 8)
The optical fiber bonding apparatus according to appendix 7, wherein the hand or the stage moves the ferrule or the optical circuit so that the size of the contact area becomes larger.
(Appendix 9)
The imaging unit includes an imaging camera;
A polarizing plate that transmits light incident on the imaging camera;
The optical fiber bonding apparatus according to appendix 7 or 8, characterized by comprising:
(Appendix 10)
The optical fiber bonding apparatus according to appendix 9, further comprising a color filter that transmits light incident on the imaging camera.
(Appendix 11)
11. The optical fiber bonding apparatus according to any one of appendices 7 to 10, wherein the light emitted from the light source is red light.
(Appendix 12)
The optical fiber bonding apparatus according to any one of appendices 7 to 11, wherein the hand is provided with a force sensor for detecting contact between the ferrule and the optical circuit.

10 PLC
DESCRIPTION OF SYMBOLS 11 Joining surface 20 Ferrule 21 Joining surface 22 Upper surface 23 Bottom surface 30 Housing | casing 50 Optical fiber 60a, 60b, 60c, 60d, 60e Contact | adherence area | region 110 Stage 115 Stage controller driver 120 Hand 121 Force sensor 125 Hand controller driver 126 Sensor amplifier 130 Light source 140 Imaging unit 141 Imaging camera 142 Imaging lens 143 Polarizing plate 144 Color filter 150 Control unit

Claims (5)

An imaging step of imaging the joint surface of the ferrule joined to the end face of the optical fiber and the joint surface of the optical circuit joined to the joint surface of the ferrule;
A contact step of bringing the joint surface of the ferrule into contact with the joint surface of the optical circuit;
The position of the ferrule or the optical circuit is adjusted based on a contact area where light generated on the joint surface of the ferrule is not detected by bringing the joint surface of the ferrule and the joint surface of the optical circuit into contact with each other. Adjustment process;
After the adjustment step, a joining step for joining the ferrule and the optical circuit;
An optical fiber bonding method comprising:   2. The optical fiber bonding method according to claim 1, wherein the adjustment step is performed so that a length value and a width value in the adhesion region are both equal to or greater than a predetermined value. . A hand on which a ferrule bonded to the end face of the optical fiber is installed;
A stage on which an optical circuit having a bonding surface to be bonded to the bonding surface of the ferrule is installed;
An imaging unit that is installed at a position where the totally reflected light is detected on the joint surface of the ferrule, and that images the joint surface of the ferrule and the joint surface of the optical circuit;
A light source for irradiating light to the joint surface of the ferrule and the joint surface of the optical circuit;
Have
When the joint surface of the ferrule and the joint surface of the optical circuit are brought into contact with each other, a contact region where light is not detected in the imaging unit, which is generated on the joint surface of the ferrule, is detected, and adjustment based on the contact region is performed. An optical fiber bonding apparatus for bonding the ferrule and the optical circuit. The imaging unit includes an imaging camera;
A polarizing plate that transmits light incident on the imaging camera;
The optical fiber bonding apparatus according to claim 3, wherein:   The optical fiber bonding apparatus according to claim 4, further comprising a color filter that transmits light incident on the imaging camera.

Images