| 摘要 |
<p>A photonic bandgap fiber of the present invention functions as a polarization maintaining fiber, and includes: a core made from a solid material; a cladding provided around the core; a periodic structure region which is provided in a part of the cladding in a vicinity of the core and in which a plurality of high refractive index parts with a refractive index higher than that of the cladding are arranged in a periodic structure; a low refractive index region which is provided in another part of the cladding in a vicinity of the core and has an average refractive index lower than that of the core; and stress applying parts which are provided in a part of the low refractive index region close to the periodic structure region and have a thermal expansion coefficient different from that of another part of the low refractive index region.</p> |
