OPTICAL FIBER, FIBER LASER, AND METHOD FOR MANUFACTURING OPTICAL FIBER

摘要

This optical fiber (10) is provided with a core (12), a first clad (14a) in contact with the core (12), and a second clad (14b) provided around the first clad (12). The core (12) has a higher refractive index than the first clad (14a), and the first clad (14a) has a higher refractive index than the second clad (14b). In a cross-section, the length of the core (12) measured along a first direction is different from the length of the core measured along a second direction.