TITLE:
An Improved Design for an All-Optical Flip-Flop Based on a Nonlinear 3-Sections DFB Laser Cavity
AUTHORS:
Hossam Zoweil
KEYWORDS:
All-Optical Flip-Flop, Distributed Feedback Laser, Nonlinearity, Switching
JOURNAL NAME:
Optics and Photonics Journal,
Vol.6 No.5,
May
30,
2016
ABSTRACT: A new all optical flip-flop based on a 3-sections nonlinear semiconductor
DFB laser structure is proposed and simulated. The operation of the device does
not require a holding beam. Electrical current injection into an active layer
provides optical gain to the laser mode. The wave-guiding layer consists of a
linear grating section centered between 2 detuned nonlinear grating sections.
The average refractive index in the nonlinear sections is slightly higher than
the refractive index of the middle section. A negative nonlinear refractive
index coefficient exists along the nonlinear sections. In the “OFF” state, the
DFB structure does not provide enough optical feedback to lase due to the
detuned sections. At high light intensity in structure, “ON” state, detuning
decreases and the DFB structure allows for a laser mode that sustains the
decrease in detuning to exist. The nonlinearity is provided by direct photon
absorption at the Urbach tail. Numerical simulations using GPGPU computing show
nanoseconds transition times between “OFF” and “ON” states.