JP4242818B2 - Optical fiber grating manufacturing method and manufacturing apparatus - Google Patents

Description

  The present invention relates to an optical fiber grating manufacturing method and manufacturing apparatus, and more particularly to an optical fiber grating manufacturing method and manufacturing apparatus for manufacturing a plurality of gratings having different periods in the same region of an optical fiber.

  Conventionally, in order to reduce the size and improve the characteristics of an optical fiber grating, a plurality of gratings having different periods have been manufactured at the same location of the optical fiber.

As disclosed in Patent Document 1, an optical fiber grating is usually manufactured by irradiating a phase mask with a laser and exposing a core with an interference pattern by diffracted light from the phase mask. When a plurality of gratings having different periods are produced at the same place, the grating is produced by performing exposure by exchanging the phase mask with one having a different period (see, for example, Patent Document 2).
Japanese Patent No. 2929569 JP-A-10-293222

  In the conventional phase mask method for producing a grating by exposing an interference pattern by diffracted light from a phase mask, if the position of the phase mask and the optical fiber shifts during the exposure, a periodic refractive index change occurs. The contrast is deteriorated, and the grating characteristics are deteriorated.

 For example, in order to produce a grating that reflects in the 1550 nm band, which is most often used in optical communications, a grating with a period of about 0.5 microns is necessary, and in order to perform stable exposure, a position on the order of several tens of nanometers is required. Control is required.

 For this reason, as shown in Japanese Patent Application Laid-Open No. 2003-29057, measures such as fixing the optical fiber by a special device have been required. In addition, since the positional relationship between the phase mask and the optical fiber changes due to ambient vibrations and temperature changes, measures such as vibration suppression and temperature management are required.

 In the case of interference exposure by the phase mask method, the phase mask and the optical fiber need to be placed at a close distance of several tens of microns to several hundreds of microns, and accurate position adjustment is necessary.

 Therefore, when producing multiple gratings with different periods at the same location, the production method in which exposure is performed by exchanging the phase mask with a different period, the position adjustment with high accuracy is performed each time the phase mask is exchanged. It was necessary.

  On the other hand, even if a phase mask with the same period was used, it was possible to produce gratings with different periods by adjusting the lens in the middle of the exposure system and changing the tension on the optical fiber, but the variable range was small. It was a thing.

  Further, in any of these methods, since the exposure method is complicated, it is difficult to produce a plurality of optical fiber gratings, and there is a problem that the yield is low and the price is high.

  The present invention has been made in view of the above, and the purpose thereof is to eliminate vibration measures, temperature management, phase mask replacement and high-accuracy position adjustment, and to easily and efficiently add a plurality of gratings to the same region. An object of the present invention is to provide an optical fiber grating manufacturing method and manufacturing apparatus that can be manufactured.

An optical fiber grating manufacturing method of the present invention, using an optical fiber coated with a thermoplastic UV-transparent resin surrounding the steps of softening by heating the thermoplastic UV-transparent resin coated around the optical fiber, grating A plurality of phase modulation patterns with different periods are formed by pressing a plurality of phase modulation pattern molds having different periods in which periodic grooves corresponding to the periods are softened to the plurality of surfaces at the same position in the longitudinal direction of the thermoplastic ultraviolet transmitting resin. A process of transferring
A step of removing the plurality of phase-modulation pattern type from the thermoplastic UV-transparent resin, characterized in that a step of irradiating a laser beam to the optical fiber through the plurality of phase modulation pattern transferred.

Further, in the optical fiber grating manufacturing method of the present invention, the step of irradiating the optical fiber with the laser simultaneously irradiates each of the plurality of surfaces onto which the plurality of phase modulation patterns of the optical fiber are transferred. And

Further, in the optical fiber grating manufacturing method of the present invention, the step of irradiating the optical fiber with the laser irradiates the plurality of surfaces of the optical fiber onto which the plurality of phase modulation patterns are transferred one by one. And

In the optical fiber grating manufacturing method of the present invention, the step of irradiating the optical fiber with a laser irradiates the laser while rotating the optical fiber.

  Further, in the optical fiber grating manufacturing method of the present invention, the plurality of phase modulation pattern molds have the plurality of phases transferred when the wavelength of the laser is λ and the refractive index of the thermoplastic ultraviolet transmitting resin is n. The groove depth d of the modulation pattern satisfies d = λ / (2 (n−1)).

Further, the optical fiber grating manufacturing method of the present invention, as a pre-step of the step of irradiating the laser to the optical fiber, characterized by having a step of diffusing hydrogen or deuterium into the optical fiber.

 Further, the optical fiber grating manufacturing apparatus of the present invention includes an optical fiber delivery unit that sends out an optical fiber coated with a thermoplastic ultraviolet transmissive resin, and the thermoplastic ultraviolet ray that coats the optical fiber delivered from the optical fiber delivery unit. The same position in the longitudinal direction of the thermoplastic UV transmissive resin that softens the heating unit that heats and softens the transmissive resin and a plurality of phase modulation pattern molds with different periods in which periodic grooves corresponding to the period of the grating are engraved A mold pressing unit that presses against a plurality of surfaces and transfers a plurality of phase modulation patterns having different periods, a laser generation unit that generates a laser, a beam splitter that separates the laser generated from the laser generation unit into two, and One of the two lasers separated by the beam splitter is reflected to direct the laser in both directions of the optical fiber. A plurality of mirrors forming an optical path so as to Isa, characterized by comprising an optical fiber take-up unit for taking up the laser optical fiber in which a plurality of grating is formed by irradiation of.

Further, the optical fiber grating manufacturing apparatus of the present invention includes a first rotating part that is rotatable and holds one end of an optical fiber that is coated with a thermoplastic ultraviolet transmitting resin and onto which a plurality of phase modulation patterns are transferred in the longitudinal direction. A second rotating unit that holds and rotates the other end of the optical fiber, a laser generating unit that generates a laser, and a mirror that reflects the laser generated from the laser generating unit and irradiates the optical fiber A heating unit that heats and softens the thermoplastic ultraviolet transmissive resin; and a plurality of phase modulation pattern molds having different periods in which periodic grooves corresponding to the periphery of the grating are softened. And a die pressing unit that presses against a plurality of surfaces at the same position in the longitudinal direction and transfers a plurality of phase modulation patterns having different periods .

 According to the method for producing an optical fiber grating of the present invention, a plurality of phase modulation patterns are transferred to a thermoplastic ultraviolet transparent resin covering the periphery of the optical fiber, and a laser is irradiated to the optical fiber through the transferred phase modulation patterns. Therefore, it is possible to easily and efficiently produce a plurality of gratings in the same region without taking measures against vibration, temperature management, phase mask replacement, or high-accuracy position adjustment.

 Further, according to the optical fiber grating manufacturing apparatus of the present invention, a plurality of phase modulation patterns are transferred to the thermoplastic ultraviolet ray transmissive resin covering the periphery of the optical fiber, and the laser is turned into the optical fiber through the transferred phase modulation patterns. Since irradiation is performed, it is possible to easily and efficiently produce a plurality of gratings in the same region without performing vibration countermeasures, temperature management, phase mask replacement, or highly accurate position adjustment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Example 1)
Example 1 of the optical fiber grating manufacturing method of the present invention will be described with reference to the flowchart shown in FIG. 1 and FIGS. 2-1 and 2-2.

  First, in step S110, as shown in FIG. 2-1 (a), an optical fiber 1 whose periphery is coated (coated) with a thermoplastic ultraviolet transmitting resin 11 made of, for example, a fluorine resin is prepared.

  Here, as a coating method, a part of the optical fiber coated with a normal ultraviolet curable resin is removed and a thermoplastic ultraviolet transmitting resin is coated on the part (recoating method), and the optical fiber is a base material. There is a method of coating when drawing from.

The method of coating at the time of drawing from the base material has an advantage that the breaking strength of the optical fiber is hardly deteriorated because it is not necessary to remove the coating at the time of exposure. Further, since the coating removal process and the recoating process are not required, man-hours can be reduced and an inexpensive optical fiber grating can be manufactured.

 On the other hand, the recoating method has an advantage that a normal optical fiber can be used because only a part of the thermoplastic ultraviolet transmitting resin is used.

  Next, as shown in FIG. 2-1 (b), the optical fiber 1 is placed on the phase modulation pattern mold 31, and the phase modulation pattern mold 32 having a different period is further placed thereon. The second phase modulation pattern molds 31 and 32 are sandwiched.

  In step S120, the heaters 21 and 22 heated to a temperature equal to or higher than the resin softening temperature (110 ° C.) are pressed so as to sandwich the first and second phase modulation pattern molds 31 and 32, and the thermoplastic ultraviolet transparent resin 11 is softened. In step S130, the first and second phase modulation pattern molds 31 and 32 are pressed against the thermoplastic ultraviolet transparent resin 11. Here, the temperature needs to be not less than the softening temperature and not more than the decomposition temperature (about 100 ° C. to 200 ° C.) of the thermoplastic ultraviolet transparent resin 11.

 As the first and second phase modulation pattern molds 31 and 32, a conventional quartz phase mask can be used. However, unlike normal exposure, it is not necessary to transmit ultraviolet light unlike quartz, and other than quartz. These materials (for example, silicon) may be used.

 Next, in steps S140 and S150, as shown in FIG. 2-1 (c), the softening heating portion 14 is cooled to the curing temperature as necessary, and the first and second phase modulation pattern molds 31 and 32 are removed. . The cooling is performed when the first and second phase modulation pattern molds 31 and 32 are removed when the thermoplastic ultraviolet transparent resin 11 is too soft at a high temperature. This is because the resin remains in the groove and the phase modulation pattern cannot be transferred.

  Next, in step S160, the optical fiber 1 is irradiated with the ultraviolet laser 4 as shown in FIG. First, the optical fiber 1 is irradiated with the ultraviolet laser 4 through the first phase modulation pattern portion 14 transferred by the first phase modulation pattern mold 31. As the laser, an excimer laser, a second harmonic of an argon laser, a second harmonic of a copper vapor laser, a fourth harmonic of a YAG laser, or the like can be used.

  The ultraviolet laser 4 that has passed through the first phase modulation pattern portion 14 is diffracted and separated into ± first-order light 5, but the ± first-order light 5 overlaps as shown in FIG. Where they meet, interference fringes produce a periodic pattern of ultraviolet light. Then, the refractive index of the core 12 of the optical fiber 1 periodically rises corresponding to the intensity distribution of the ultraviolet laser 4, and the grating corresponding to the first phase modulation pattern portion 14 is completed.

  Thereafter, the optical fiber 1 is turned upside down and irradiated with the ultraviolet laser 4 through the second phase modulation pattern portion 15 to complete the grating corresponding to the second phase modulation pattern portion 15 as described above. As shown in FIG. 2-2 (f), a plurality of grating portions 16 in which the gratings corresponding to the first and second phase modulation pattern portions 14 and 15 are formed in the same region are completed.

The optical fiber 1 to be used is only required to be sensitive to ultraviolet light, but it is desirable that the optical sensitivity is high. For example, before step S110, between step S110 and step S120, step S150 and step S160. By introducing a process of hydrogen treatment for diffusing hydrogen or deuterium into the optical fiber 1 at a stage before exposure, such as between and, the characteristics of the optical fiber 1 can be improved.

When the wavelength λ of the ultraviolet laser 4 used at the time of exposure and the refractive index n of the thermoplastic ultraviolet transmitting resin 11 are used, the groove depth d after the phase modulation pattern transfer shown in FIG.
d = λ / (2 (n−1)) (Formula 1)
When the first and second phase modulation pattern types 31 and 32 satisfying the above are used, the diffraction efficiency of the 0th-order light 6 shown in FIG. 2-2 (e) can be reduced. Decreasing the 0th-order light 6 is desirable because the ± 1st-order light 5 becomes stronger and a grating can be produced efficiently. However, even if the zero-order light 6 is present, the grating can be manufactured if the ± first-order light 5 is present, and therefore this condition does not necessarily have to be satisfied.

  According to the present embodiment, the first and second phase modulation pattern portions 14 and 15 are formed on the thermoplastic ultraviolet light transmissive resin 11 covering the periphery of the optical fiber 1, and the first and second phase modulation pattern portions 14 are formed. , 15 irradiates the optical fiber 1 with the ultraviolet laser 4, so that it is not necessary to use a phase mask at the time of exposure. Also, two gratings with different periods can be produced in the same region without exchanging the phase mask, and there is no need to adjust the distance between the phase mask and the optical fiber.

(Example 2)
Next, Embodiment 2 of the optical fiber grating manufacturing method of the present invention will be described with reference to the flowchart shown in FIG. 3 and FIGS. In addition, the same code | symbol is attached | subjected to the structure same as the structure of Example 1 shown in FIG. 2, and detailed description is abbreviate | omitted.

  In this example, the optical fiber 10 was covered with an ultraviolet light transmission type fluororesin by a recoating method. A single mode optical fiber (manufactured by Fujikura: trade name Future Guide (registered trademark) -SM) was used as the optical fiber 10. First, in step S310, the coating of the optical fiber 10 was removed by 5 cm, and the ultraviolet light transmitting fluororesin was coated on the coating removal portion. As a coating method, coating was performed by a dice method using a solution obtained by dissolving an ultraviolet light transmissive fluororesin in a solvent. Thereafter, the recoat portion was heated at 200 ° C. for 10 minutes in order to completely evaporate the solvent and cure the fluororesin. The outer diameter of the recoat portion was 160 μm.

  The used ultraviolet light transmission type fluororesin has a tensile modulus of 1000 MPa and a resin decomposition temperature of 390 ° C.

  Next, as shown in FIG. 4A, the ultraviolet light transmitting fluororesin-coated portion is placed on the phase modulation pattern mold 31, and the phase modulation pattern mold 32 having a different period is further placed thereon, and the optical fiber 10. Is sandwiched between the first and second phase modulation pattern molds 31 and 32.

  The period of the first phase modulation pattern mold 31 is 1.08 μm, and the period of the second phase modulation pattern mold 32 is 1.075 μm. Both the phase modulation patterns extend over 10 mm, and gradually increase in depth as they move away from the center. A mold in which the pattern for apodizing grating that becomes shallower was used.

 Then, in steps S320 and S330, the heaters 21 and 22 heated to the resin softening temperature or higher (110 ° C.) are pressed so as to sandwich the first and second phase modulation pattern molds 31 and 32, and the ultraviolet light transmitting fluororesin The covering portion was softened, and the first and second phase modulation pattern molds 31 and 32 were pressed against the optical fiber 10.

  The heaters 21 and 22 used are made of aluminum with good heat conductivity and are 20 mm in length. The springs 21 and 22 are adjusted to push the covering portion with a force of 2 kg using a spring, and the first and second phase modulation pattern molds 31, The pressure was maintained for about 100 seconds until 32 and the optical fiber 10 were warmed.

  Thereafter, in step S340, the heaters 21 and 22 are removed and the optical fiber 10 is allowed to cool to room temperature. In step S350, the heaters 21 and 22 are removed from the first and second phase modulation pattern molds 31 and 32.

  Thereafter, the laser 7 was irradiated from the phase modulation pattern transfer side of the ultraviolet light transmission type fluororesin coating portion, and a grating was written in the optical fiber 10 by diffraction by the phase modulation pattern on the coating surface. As the laser 7, an argon ion laser second harmonic (244 nm) was used.

  At this time, as shown in FIG. 4B, the laser 7 was divided into two by a beam splitter and exposed from both sides so that the phase modulation pattern carved on both sides could be irradiated. Further, in order to uniformly expose the entire phase modulation pattern, the optical fiber 10 was moved 10 mm or more to which the phase modulation pattern was transferred in the longitudinal direction.

  FIG. 5 shows the reflection characteristics of the multiple optical fiber gratings produced in this example. It was confirmed that two gratings having different reflection wavelengths (for example, 1546 nm and 1551 nm) can be exposed without interfering with each other.

(Example 3)
Next, Embodiment 3 of the optical fiber grating manufacturing method of the present invention will be described with reference to FIGS.

In the present example, the phase modulation pattern was transferred to the coated portion of the optical fiber 10 in the same process as steps S310 to S350 of the second example.

  Thereafter, the laser 7 was irradiated from the phase modulation pattern transfer side of the ultraviolet light transmission type fluororesin coating portion, and a grating was written in the optical fiber 10 by diffraction by the phase modulation pattern on the coating surface. As the laser 7, an argon ion laser second harmonic (244 nm) was used.

  At this time, exposure was performed from one side while rotating the optical fiber 10 as shown in FIG. 6 so that the phase modulation patterns carved on both sides could be irradiated. Further, in order to uniformly expose the entire phase modulation pattern, the optical fiber 10 was moved 10 mm or more to which the phase modulation pattern was transferred in the longitudinal direction.

  The reflection characteristics of the optical fiber grating produced in this example are the same as those produced in Example 2 as shown in FIG. It was confirmed that two gratings having different reflection wavelengths (for example, 1546 nm and 1551 nm) can be exposed without interfering with each other.

(Example 4)
Next, Embodiment 4 of the optical fiber grating manufacturing method of the present invention will be described with reference to the flowchart shown in FIG. 7 and FIGS. In addition, the same code | symbol is attached | subjected to the structure same as the structure of Example 1 and Example 2 shown in FIG.2 and FIG.4, and detailed description is abbreviate | omitted.

  In step S710, similarly to step S310 of Example 2, the optical fiber 10 was coated around the optical fiber 10 by a recoating method.

  Next, as shown in FIG. 8, the ultraviolet light transmission type fluororesin-coated portion is placed on the phase modulation pattern mold 31, the phase modulation pattern mold 32 having a different period is further placed thereon, and the optical fiber 10 is the first The second phase modulation pattern molds 31 and 32 are sandwiched. The first and second phase modulation pattern molds 31 and 32 are the same as those in the second embodiment.

  Thereafter, in step S720, the atmospheric temperature of the stamping unit 8 including the first and second phase modulation pattern molds 31 and 32 and the optical fiber 10 coated with the ultraviolet light transmitting fluororesin is heated to 100 ° C. The light transmission type fluororesin coating part was softened.

  Next, in step S730, when the temperature of the optical fiber 10 coated with the first and second phase modulation pattern molds 31 and 32 and the ultraviolet light transmitting fluororesin is stabilized at 100 ° C., the first and second phase modulation pattern molds 31 and 32 are stabilized. The optical fiber 10 was sandwiched between the phase modulation pattern molds 31 and 32 and pressure was applied. The pressing pressure was adjusted so as to push the ultraviolet light transmission type fluororesin-coated portion with a force of 2 kg using a spring, and the pressure was maintained for 3 seconds.

  In step S740, the stamped optical fiber 10 was removed from the first and second phase modulation pattern molds 31 and 32 while the ambient temperature remained at 100 ° C. Resin is prevented from remaining in the first and second phase modulation pattern molds 31 and 32 because the heating is performed at a temperature as low as the resin softening temperature that can be pressed.

  Thereafter, in step S750, the second harmonic (244 nm) of an argon ion laser was irradiated from the phase modulation pattern transfer side of the optical fiber 10, and a grating was written in the optical fiber 10 by diffraction due to the phase modulation pattern on the coating surface.

The exposure method was the same as in Example 2.

  FIG. 9 shows the reflection characteristics of the optical fiber grating produced in this example. It was confirmed that two gratings having different reflection wavelengths (for example, 1546.5 nm and 1551 nm) can be produced simultaneously as in Example 2 and Example 3.

  In the first to fourth embodiments, the method of manufacturing two gratings having different periods in the same region using two phase modulation pattern molds has been described, but the phase using three or more phase modulation pattern molds is described. By transferring the modulation pattern to the coated portion of the optical fiber, three or more gratings having different periods can be produced in the same region.

(Example 5)
Next, Example 5 of the optical fiber grating manufacturing apparatus of the present invention will be described with reference to FIG.

  FIG. 10 shows the configuration of an optical fiber grating manufacturing apparatus according to a fifth embodiment of the present invention. An optical fiber delivery unit 41 that sends out an optical fiber 1 coated with a thermoplastic ultraviolet transmitting resin by rotating a drum, and an optical fiber. First and second phase modulation pattern molds 31 and 32 disposed so as to sandwich 1 from above and below, heaters 21 and 22 disposed so as to sandwich the first and second phase modulation pattern molds 31 and 32, and The laser generator 17 for generating the laser 19, the beam splitter 18 for separating the laser 19 emitted from the laser generator 17 into two lasers 19a and 19b, and the two directions of the optical fiber 1 by reflecting the laser 19b Mirrors 51, 52, and 53 that form an optical path so as to irradiate lasers 19a and 19b, and lasers 19a and 19b. Computing is an optical fiber take-up unit 42 for winding the optical fiber 1 by rotating the drum that have been written.

 Here, the basic operation of the optical fiber grating manufacturing apparatus of the present embodiment will be described. The optical fiber delivery unit 41 sends out the optical fiber 1 covered with the thermoplastic ultraviolet ray transmitting resin from the drum.

  The first and second phase modulation pattern molds 31 and 32 sandwich the optical fiber 1 from above and below, and the heaters 21 and 22 heated to the resin softening temperature or higher (110 ° C.) are the first and second phase modulation pattern molds. The coated portions of the optical fiber 1 are softened by pressing them 31 and 32, and the first and second phase modulation pattern molds 31 and 32 are pressed against the optical fiber 1 to transfer the phase modulation pattern.

  On the other hand, the laser generator 17 generates a laser 19 toward the beam splitter 18. The beam splitter 18 divides the laser 19 into two lasers 19 a and 19 b, and irradiates the laser 19 a on the portion of the optical fiber 1 where the grating is written.

  The mirrors 51, 52, and 53 reflect the laser 19b and irradiate the portion of the optical fiber 1 where the grating is written from the opposite direction of the laser 19a.

  The optical fiber take-up unit 42 takes up the optical fiber 1 on which the grating is written upon irradiation of the lasers 19a and 19b, on a drum.

  According to the optical fiber grating manufacturing apparatus of the present embodiment, two phase modulation patterns are transferred to the thermoplastic ultraviolet transmitting resin covering the periphery of the optical fiber 1, and the lasers 19a and 19b are transmitted through the transferred two phase modulation patterns. Since it irradiates the optical fiber, it is not necessary to use a phase mask during exposure, and since it is not affected by ambient vibrations or temperature changes, vibration measures and temperature management are not necessary. Also, two gratings with different periods can be produced in the same region without exchanging the phase mask, and there is no need to adjust the distance between the phase mask and the optical fiber.

  Further, since the exposure can be performed while moving the optical fiber 1, continuous flow exposure is possible, and the efficiency of the optical fiber grating manufacturing work can be improved.

(Example 6)
Next, Example 6 of the optical fiber grating manufacturing apparatus of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as the structure of Example 5 shown in FIG. 10, and detailed description is abbreviate | omitted.

  FIG. 11 (a) shows the configuration of Example 6 of the optical fiber grating manufacturing apparatus of the present invention, which is covered with a thermoplastic ultraviolet transmitting resin, and phase modulation patterns are transferred to a plurality of surfaces at the same position in the longitudinal direction. A first rotating unit 61 that can rotate while holding one end of the optical fiber 1, a second rotating unit 62 that can rotate while holding the other end of the optical fiber 1, and a laser generator that generates a laser 19 And a mirror 54 that reflects the laser 19 generated from the laser generator 17 and irradiates the optical fiber 1.

  Here, the basic operation of the optical fiber grating manufacturing apparatus of the present embodiment will be described.

  The laser generator 17 generates a laser 19. The mirror 54 reflects the laser 19 and irradiates the portion of the optical fiber 1 where the grating is written.

  In order to uniformly expose the entire area of the phase modulation pattern, the first and second rotating portions 61 and 62 rotate in the longitudinal direction more than the length of the phase modulation pattern transferred to the optical fiber 1 while rotating the optical fiber 1. Translate.

  As shown in FIG. 11B, the first and second rotating parts 61 and 62 are composed of a cylindrical body 6a, a rotating body 6b, and a holding part 6c. The rotating body 6b is rotatably attached to the inner wall of the cylindrical body 6a, and the holding portion 6c fixed to the rotating body 6b holds the optical fiber 1 and can rotate with the rotating body 6b.

  According to the optical fiber grating manufacturing apparatus of the present embodiment, a plurality of phase modulations transferred to the optical fiber 1 coated with a thermoplastic ultraviolet ray transmissive resin and having phase modulation patterns transferred to a plurality of surfaces at the same position in the longitudinal direction. Since the laser 19 is irradiated through the pattern, it is not necessary to use a phase mask at the time of exposure, and vibration countermeasures and temperature management are not required because it is not affected by ambient vibrations or temperature changes. Also, two gratings with different periods can be produced in the same region without exchanging the phase mask, and there is no need to adjust the distance between the phase mask and the optical fiber.

It is a flowchart which shows the preparation procedure in Example 1 of the optical fiber grating preparation method of this invention. It is the schematic explaining the preparation procedure in Example 1 of the optical fiber grating preparation method of this invention. It is the schematic explaining the preparation procedure in Example 1 of the optical fiber grating preparation method of this invention. It is a flowchart which shows the preparation procedure in Example 2 of the optical fiber grating preparation method of this invention. It is the schematic explaining the heating and exposure method in Example 2 of the optical fiber grating manufacturing method of this invention. It is a graph which shows the reflective characteristic of the multiple optical fiber grating produced in Example 2 and 3 of the optical fiber grating production method of this invention. It is the schematic explaining the exposure method in Example 3 of the optical fiber grating manufacturing method of this invention. It is a flowchart which shows the preparation procedure in Example 4 of the optical fiber grating preparation method of this invention. It is the schematic explaining the heating method in Example 4 of the manufacturing method of the optical fiber grating of this invention. It is a graph which shows the reflective characteristic of the multiple optical fiber grating produced in Example 4 of the optical fiber grating production method of this invention. It is a block diagram which shows Example 5 of the optical fiber grating production apparatus of this invention. It is a block diagram which shows Example 6 of the optical fiber grating production apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10 Optical fiber 11 Thermoplastic ultraviolet transparent resin 12 Core 13 Clad 14 1st phase modulation pattern part 15 2nd phase modulation pattern part 16 Multiple grating part 17 Laser generation part 18 Beam splitter 19, 19a, 19b, 7 Laser 21, 22 Heater 31 First phase modulation pattern type 32 Second phase modulation pattern type 4 Ultraviolet laser 5 ± 1st order light 6 0th order light 41 Optical fiber delivery part 42 Optical fiber winding parts 51, 52, 53, 54 Mirror 61 First Rotating Unit 62 Second Rotating Unit 6a Tube 6b Rotating Body 6c Holding Unit 8 Embossing Unit

Claims (8)

A step of using an optical fiber around coated with a thermoplastic UV-transparent resin, is softened by heating the thermoplastic UV-transparent resin coated around the optical fiber,
A plurality of phase modulation pattern molds with different periodic periods corresponding to the period of the grating are pressed against a plurality of surfaces at the same position in the longitudinal direction of the thermoplastic ultraviolet transparent resin softened, and a plurality of phases with different periods a step of transferring the modulation pattern,
A step of removing the plurality of phase-modulation pattern type from the thermoplastic UV-transparent resin,
An optical fiber grating manufacturing method characterized by a step of irradiating a laser beam to the optical fiber through the plurality of phase modulation pattern transferred. 2. The optical fiber grating fabrication according to claim 1, wherein the step of irradiating the optical fiber with the laser simultaneously irradiates each of a plurality of surfaces of the optical fiber onto which the plurality of phase modulation patterns are transferred. Method. 2. The optical fiber grating fabrication according to claim 1, wherein in the step of irradiating the optical fiber with a laser, the plurality of surfaces of the optical fiber onto which the plurality of phase modulation patterns are transferred are irradiated one by one with the laser. Method. The method of manufacturing an optical fiber grating according to claim 1, wherein in the step of irradiating the optical fiber with the laser, the laser is irradiated while rotating the optical fiber.   In the plurality of phase modulation pattern types, when the wavelength of the laser is λ and the refractive index of the thermoplastic ultraviolet transmitting resin is n, the groove depth d of the plurality of phase modulation patterns to be transferred is d = λ / The optical fiber grating manufacturing method according to any one of claims 1 to 4, wherein (2 (n-1)) is satisfied. As pre-process step of irradiating a laser beam to the optical fiber, the optical fiber grating according to any one of claims 1 to 4, characterized in that a step of diffusing hydrogen or deuterium into said optical fiber Manufacturing method. An optical fiber delivery section for delivering an optical fiber coated with a thermoplastic ultraviolet transparent resin;
A heating unit that heats and softens the thermoplastic ultraviolet transmitting resin that covers the optical fiber delivered from the optical fiber delivery unit;
A plurality of phase modulation pattern molds with different periodic periods corresponding to the period of the grating are pressed against a plurality of surfaces at the same position in the longitudinal direction of the thermoplastic ultraviolet transparent resin softened, and a plurality of phases with different periods An embossing part for transferring the modulation pattern;
A laser generator for generating a laser;
A beam splitter that separates the laser generated from the laser generator into two;
A number of mirrors that reflect one of the two lasers separated by the beam splitter and irradiate the laser in both directions of the optical fiber;
An optical fiber grating manufacturing apparatus comprising: an optical fiber winding unit that winds the optical fiber on which a plurality of gratings are formed by laser irradiation. A first rotating section that is coated with a thermoplastic ultraviolet transparent resin, holds one end of an optical fiber having a plurality of phase modulation patterns transferred in the longitudinal direction , and is rotatable;
A second rotating part that holds the other end of the optical fiber and is rotatable;
A laser generator for generating a laser;
A mirror that reflects the laser generated from the laser generator and irradiates the optical fiber;
A heating section for overheating and softening the thermoplastic ultraviolet transparent resin;
A plurality of phase modulation pattern molds with different periods engraved with periodic grooves corresponding to the periphery of the grating are pressed against a plurality of surfaces at the same position in the longitudinal direction of the thermoplastic ultraviolet transparent resin, and a plurality of phases with different periods An apparatus for producing an optical fiber grating, comprising: a mold pressing portion for transferring a modulation pattern .

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