| 摘要 |
<p>An optical waveguide of a system in which the diameter of a core is constant in the optical wave propagation direction with the diameter of a mode field at input and output ends increased by reducing Δn toward the input and output ends, a difference Δn between refractive indexes of a core and a clad of the waveguide along the optical wave propagation direction for improving a coupling efficiency and tolerance in a connecting operation having a Δn variation region in which Δn varies from Δn1 to Δn2 (Δn1 > Δn2), a cross-sectional shape of the core not varying in the optical wave propagation direction, characterized in that an X-Y plot in which the X and Y axes represent the coordinates of Δn variation region in the optical wave propagation direction and Δn respectively projects downward, and an optical fiber.</p> |
