Optical branching filter

Abstract

Abstract PURPOSE:To achieve the improvement in wavelength resolution by detecting the light being radiated from the bent parts of an optical guide with the photo detectors in the media of refractive indices different from that of the clad. CONSTITUTION:The light entering a single mode optical guide 1 is made to the guide light by the core 4 and the radiation light by the clad 8 of a refractive index lower than that of the core 4 at the bent parts of the optical guide 1. Coupling of both of the light becomes maximum when the conditions of the formulas I, II are satisfied, then the guide light is converted to the radiation light and the strong radiation light leaks into the covering of a refractive index lower than that of the clad 8. This leaking light is detected by the photo detectors 2a ... in the media 3a by way of the media 3a ... of refractive indices approximately the same as that of the clad 8 enclosing the outside of the bent parts 1a. Hence, if the bent parts 1a, 1b ... of different radii R are provided, the light may be branched at high resolution based on the formulas I, II. (In the formulas b; the half-amplitude level of clad, n2: the refractive index of the clad, beta: the phase constant of the guide mode, k: the number of waves of light in free space, N: integer.)

Inventors

• 👤 Taiji Murakami
• 👤 Haruhiko Tsuchiya
• 👤 Yoshinori Kato

Bibliographic Details