Bragg grating, and spectroscopy device including the Bragg grating

A Bragg grating disposed at each of opposite ends of a resonator for reflecting light of a certain wavelength band, the Bragg grating comprising:

• a core member extending from a waveguide of the resonator in a lengthwise direction of the waveguide;
• a plurality of first refractive members protruding from the core member in a width direction of the core member, the width direction being perpendicular to the lengthwise direction of the waveguide;
• and
• a second refractive member filling spaces between the first refractive members,
• wherein pitches between the plurality of first refractive members vary along the lengthwise direction,
• wherein a protruding length of each of the plurality of first refractive members protruding in the width direction gradually increases along the lengthwise direction toward a center of the core member,
• wherein a protruding length of a first refractive member protruding from the center of the core member has a maximum value in comparison with all other of the plurality of first refractive members,
• wherein a width of the core member in the width direction gradually reduces along the lengthwise direction of the core member toward the center of the core member, and
• wherein the width of the core member at the center of the core member has a minimum value in comparison with all other widths of the core member.