| 摘要 |
An optical coupler is to be specified which is designed using planar optical waveguide technology, has a high wavelength selectivity, and at the same time has a structural length which is as short as possible. Two planar waveguides (WL1, WL2), coupled to one another, are designed with respect to their cross-sectional dimensions and to their refractive indices in such a manner that the fundamental modes of the two optical waveguides (WL1, WL2) in the case of a predetermined wavelength have the same phase coefficients and in the case of all the other wavelengths have different phase coefficients. The two optical waveguides (WL1, WL2) unite in a partial region of the coupler to form a common optical waveguide (WL), and this common optical waveguide (WL) has such cross-sectional dimensions and such a length that two modes (eigenwaves, natural waves), propagating therein, of the coupler, into which waves a fundamental wave is split up which has been fed into one of the two waveguides in front of the common waveguide (WL), are subjected in the case of the predetermined wavelength to such a mutual shift in their phase coefficients that the modes are subjected after the common waveguide (WL) in one of the two waveguides (WL1, WL2) to a superposition in phase opposition and in the other waveguide to an equiphase superposition. An optical coupler of this kind is well suited, due to its short structural length, for monolithic integration (Fig. 1). <IMAGE>
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