| 摘要 |
PROBLEM TO BE SOLVED: To provide a wavelength selective filter capable of optically coupling optical fibers together without using a lens. SOLUTION: This wavelength selective filter 1 is constituted essentially of a central part 6 consisting of liquid crystal etalon and interposed by translucent substrates 7 and 8. Further, translucent substrate 7 and 8 have refractive index distributing parts 9 and 10 having prescribed refractive index distributions formed in the regions to be optically coupled together with optical fibers 2 and 3 within the substrates respectively. And expansion of beam waists are controlled by the refractive index distributing parts 9 and 10. |
