| 摘要 |
A photonic band gap fiber comprising a first core having a refractive index up to that of a clad, a second core provided to surround the first core and having a refractive index lower than that of the first core, a clad surrounding the second core, and a periodic structure portion that includes a high refractive index portion having a refractive index higher than that of the clad and formed in a periodic structure and is provided in proximity to the second core of the clad. In the periodic structure, propagation constant of the basic mode of at least working wavelength exists in the photonic band gap, and propagation constant of the high order mode of working wavelength exists on the outside of the photonic band gap. |
