Optical power splitter and polarization splitter
AssigneeAmerican Telephone and Telegraph Company, AT&T Bell Laboratories
InventorGail A. Bogert
Life of this patent
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Abstract
A 3.times.3 optical guiding arrangement is disclosed for providing both power splitting between a pair of output guides in the 3.times.3 guide structure and polarization splitting (into the TE and TM modes) between the central guide and the pair of outer guides. In accordance with the present invention, the mutual coupling length L and separation distance d between adjacent guides are chosen to provide the desired polarization splitting and total intensity (power) in the outer guides. For example, an input signal of intensity I comprising both the TE and TM modes may be launched in the center guide and with correct choices for L and d, will result in output signals of I.sub.TM /2 each of the outer pair of guides and I.sub.TE from the central guide.
Claims7
An optical guiding structure for providing splitting of both the power I of an input signal and the polarizations TE, TM (TE being defined as the transverse electric polarization and TM being defined as the transverse magnetic polarization) of said input signal, said optical guiding structure being defined as having
- a central guide and a pair of outer guides, coextensively parallel over a predetermined length L and mutually separated by a predetermined distance d, wherein the propagation constants .beta..sub.1 and .beta..sub.3 of said outer pair of guides are equal to a first propagation value .beta..sub.1 =.beta..sub.3 =.beta.;
- the predetermined length L and predetermined separation distance d defined by the relations ##EQU11## being defined as the coupling length required to completely transfer a first polarized state from one guide to an adjoining guide for a predefined pair of guides, and .gamma. being defined as the guide lateral evanscent penetration depth, the relations being solved for proscribed values of l.sub.oTM, l.sub.oTE, and .gamma..sub.TE, said predetermined length L and predetermined separation distance d thus achieving transfer of a first polarization from an input signal applied to the central guide to said outer pair of guides and allowing the second, remaining polarization to emerge from said central guide.
Dependencies are inferred from the claim text.