Apparatus for manufacturing long-period optical fiber grating

An apparatus for manufacturing a long-period fiber grating, comprising:

• a laser source outputting laser light;
• a first lens adjusting a focal point of the laser light output by said laser source;
• a dispersing unit dispersing the laser light passed through said first lens and broadening a beam of the laser light;
• a second lens collimating the dispersed laser light;
• a composite amplitude mask having a transmission area transmitting the laser light collimated by said second lens, said composite amplitude mask transmitting the laser light to an optical fiber in a period of said transmission area;
• a measuring unit measuring a coupling peak of said long-period fiber grating formed on the optical fiber by the laser light transmitted through said composite amplitude mask;
• and
• a control unit controlling a rotation angle of said composite amplitude mask to cause said measured coupling peak to occur at a desired wavelength.

An apparatus, comprising:

• a laser unit emitting laser light;
• a composite amplitude mask periodically transmitting the laser light to an optical fiber, the optical fiber having a refractive index of a core of the optical fiber periodically changed by the laser light which has passed through said composite amplitude mask;
• and
• said composite amplitude mask further comprising two amplitude masks, each of said two amplitude masks having a transmission area transmitting the laser light and a non-transmission area not transmitting the laser light, each of said two amplitude masks being equally rotated at a same angle in opposite directions to adjust a period of said composite amplitude mask.