Characteristic analysis of lossy periodic refractive index optical waveguides

By extension of the transfer-matrix technique from the real domain to the complex, complex expressions describing field distributions and eigenvalue equations are presented for both TE and TM modes of lossy periodic refractive index optical waveguides. In terms of the eigenvalue equation presented, mode propagation and loss characteristics of lossy periodic refractive index optical waveguides are analyzed. It is found that coupling interaction exists between the wells, and causes splitting of both the mode propagation constant and the made loss coefficient; as a result, corresponding mode bands are formed. It is also found that the guided structural parameters strongly influence the coupling and the mode splitting as well as the bandwidth, so these effects are also discussed in relation to the period length, the thicknesses of the wells and the barriers, and the ratio of the well thickness to the period length. (C) 1997 Society of Photo-Optical instrumentation Engineers.