| 摘要 |
PURPOSE: To attain formation based on an N=2<n> optical path by winding sits of paths around a cylinder like spiral with the same pitches to an inverse direction, making one set of optical paths cross the other set of 1/2N pieces of optical paths, and coupling with the other set of (n) pieces of optical paths. CONSTITUTION: Two sets of fibers are wound with the same spiral pitches to an inverse direction, the inputs of a coupler at a final stage Cn follows next, and composed of several sets of mutually crossing fibers F0 and F(N-1), and the outputs of the fibers are shifted only by the half of the winding pitches against the inputs. That is, the outputs of the fibers F0 and F(N-1) are shifted only by the half of the winding pitches against inputs E0 and E(N- 1). The same rule is applied to all the fibers, and couplers can be regularly distributed with angular pitchesα=4π/N in the surrounding of those rings. Thus, N=2<n> , (n) stages can be provided, 1/2N couplers are included, and an N×N type optical diffuser which executes coupling between two optical paths can be obtained.
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