All optical Flip-Flop based on a nonlinear DFB semiconductor laser: Theoretical study

• Published in: Optics communications Vol. 283; no. 3; pp. 474 - 479
• Main Authors: Zoweil, Hossam, Kashyout, A.B.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2010; Elsevier
• Subjects: All optical switching; DFB semiconductor laser; Diffraction gratings; Exact sciences and technology; Flip-Flop; Flip-flops; Fundamental areas of phenomenology (including applications); Gratings; Gratings (spectra); Lasers; Nanostructure; Nonlinear optics; Nonlinear refractive index; Nonlinearity; Optical bistability, multistability and switching, including local field effects; Optical elements, devices, and systems; Optical waveguides and coupleurs; Optics; Phase shift; Physics; Semiconductor lasers; laser diodes; Semiconductors; 42.55.Px; Flip-Flop; DFB semiconductor laser; All optical switching; Nonlinear refractive index; 42.65.Pc; Phase shift; Refractive index; Digital simulation; Diffraction gratings; Optical waveguides; Optical gain; Bragg gratings; Semiconductor lasers; Optical feedback; Optical switching; Nonlinear optics; Distributed feedback lasers; ns range
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2009.10.031

A new design of an all optical Flip-Flop is proposed. It consists of a nonlinear distributed feedback (DFB) laser. The wave guiding layer of the DFB laser consists of linear grating section followed by a nonlinear one, and both sections are separated by a phase shift section. In the OFF-state, the real part of the refractive index in the wave guiding layer forms a Bragg grating. In the ON-state, it forms a Bragg grating with a phase shift section. Optical gain is achieved by current injection in the semiconductor active layer. Nonlinearity in the nonlinear layers of the semiconductor grating was achieved by direct absorption at the edge of the absorption band (Urbach tail). Numerical simulation shows that the device switches in a nanosecond time scale.