FORMING DEVICE FOR OPTICAL WAVEGUIDE TYPE DIFFRACTION GRATING

摘要

PURPOSE: To provide an optical waveguide type diffraction grating forming device capable of forming a grating of a desired grating interval with a simple constitution. CONSTITUTION: An optical fiber 1 is the optical fiber having a Ge added core and the refractive index of a part irradiated with a laser beam whose wavelength is near a wavelength 240nm can be raised. The laser beam generated from a pulsive laser light source 4 is made to be a slit-shape through an optical system 5 to be projected on the core of the optical fiber 1. However the optical fiber 1 is moved by an automatic stage 2, output pulses corresponding to the moving amount are applied to a frequency divider part 6 by a linear encoder 3. The laser beam is projected on the fiber 1 by allowing the frequency divider part 6 to output an output signal according to the value set in a frequency dividing ratio setting part 8 and by making a laser driving part 7 operate intermittently. Thus, the part having a large refractive index can be partially formed, and a Bragg diffraction grating can be formed.