Showing papers by "Giuseppe Coppola published in 1999"
TL;DR: The spectral performances of nonideal rectangular Bragg gratings, integrated in a rib waveguide, are analyzed by a multilayer approach based on the effective-index method and a novel analytical approach that extends coupled-mode theory to the analysis of real gratings is presented.
Abstract: The spectral performances of nonideal rectangular Bragg gratings, integrated in a rib waveguide, are analyzed by a multilayer approach based on the effective-index method. The effects of errors on the photolithographic definition of the grating, that is, period and shape, and of errors on the control of etching depth are investigated. Also the influence of the stitching error, which is unavoidable when the grating is realized by means of electron-beam photolithography, is addressed. A novel analytical approach that extends coupled-mode theory to the analysis of real gratings is also presented.
23 citations
26 Nov 1999
TL;DR: Cutolo et al. as discussed by the authors proposed a silicon optoelectronic modulator based on the plasma Dispersion Effect used in conjunction with a Distributed Bragg Reflector which converts the phase shift induced by the free carriers injected by a P-i-N diode into variation of its reflectivity.
Abstract: In this paper we propose a silicon optoelectronic modulator based on the Plasma Dispersion Effect used in conjunction with a Distributed Bragg Reflector which converts the phase shift induced by the free carriers injected by a P-i-N diode into variation of its reflectivity. The device is integrated in a low-loss Silicon-On-Insulator waveguide. With respect to a previous paper [A. Cutolo et al., Appl. Phys. Lett., 71 (2), 1997] we suggest an inversion of the driving scheme; we propose to tune the Bragg mirror in the ON state, when the light passes through the mirror unchanged, and then to inject the electron-hole plasma to put the mirror in the total reflection configuration and therefore to switch the light off. In this case the two plasma-induced optical effects, that is the variation of refractive index and absorption coefficient, are concurrent and both contributing to an efficient switching of the light. This new driving scheme allows to reach better performances in terms of modulation depth efficiency; in fact we show how, in this case, a 100% modulation depth is achieved. An exhaustive description of the optical structure and its guiding properties, together with the analysis of the electrical behavior of the modulator are given. Moreover, we show how dissipated power is also reduced allowing us to design a highly optimized version of the modulator. Finally, a comparison with other interferometric structures is given and it is shown how this kind of modulator results very attractive in terms of dissipated power and reduced area occupied on chip.
12 citations