Method of processing optical fiber

1. A method of processing an optical fiber having a core and a clad, the optical fiber having a first facet and a second facet, the method comprising:

fixing the optical fiber in a state in which at least a portion thereof is bent in a predetermined curvature radius;

applying a resist to a region on the first facet at least including an entirety of the core;

irradiating the second facet with light of a predetermined wavelength so that only the resist applied to the core in the first facet is exposed to the light through an inside of the optical fiber;

developing the resist; and

forming a level gap at a boundary between the core and the clad in the first facet utilizing the resist remaining after the irradiating and the developing.

2. The method according to claim 1 , further comprising finishing at least a portion of an outer surface of the clad in a rough surface.

3. The method according to claim 1 , further comprising providing at least one coating on an outer surface of the clad.

4. The method according to claim 1 , further comprising:

providing two or more coatings on an outer surface of the clad; and

finishing at least one of interfaces between the coatings in a rough surface.

5. The method according to claim 1 , further comprising providing two or more coatings on an outer surface of the clad,

wherein UV light is used as the light of the predetermined wavelength in the irradiating, and

wherein at least one of the two or more coatings is formed of a UV-absorbing material.

6. The method according to claim 5 , wherein a coating which is one of the two or more coatings and is formed of the UV-absorbing material has a higher refractive index for the UV light than an inner adjacent coating of the coating formed of the UV-absorbing material.

7. The method according to claim 5 , wherein nylon which is opaque to the UV light is used as the UV-absorbing material.

8. The method according to claim 1 , wherein a following condition is satisfied:

20 ≦R ≦200  (1)

where R (mm) represents the predetermined curvature radius.

9. The method according to claim 1 , wherein the resist is applied to an entire region of the first facet in the applying.

10. The method according to claim 1 , wherein the resist is a negative resist.

11. The method according to claim 1 , wherein the resist is a positive resist.

12. The method according to claim 10 , wherein the forming of the level gap includes:

performing a surface treatment at least within a region close to the core on the clad in the first facet so as to generate a difference in reflectance between the region and the core; and

stripping the resist remaining on the first facet subjected to the surface treatment.

13. The method according to claim 12 , wherein the surface treatment is a treatment of vapor-depositing a metal material in a form of a thin film at least within the region close to the core on the clad in the first facet.

14. The method according to claim 1 , wherein the forming of the level gap includes:

performing an etching on a region where the resist is no longer present on the first facet; and

stripping the resist remaining on the first facet, after the etching.

15. The method according to claim 11 , wherein the forming of the level gap includes:

filling a region where the resist is no longer present in the first facet with a material that has generally the same refractive index as the optical fiber; and

stripping the resist remaining on the first facet after the filling.