Active Photonic Band-Gap Switch Based on GaInNAs Multiquantum Well

GaInNAs has been introduced to design an active switch operating at wavelength
$\lambda = 1.2855\ \mu\hbox{m}$
having high selectivity. The device is made of a mono-dimensional periodic photonic band-gap structure constituted by alternating ridge waveguide layers with different ridge heights. The periodic waveguiding structure has been designed to show the band gap in correspondence of the wavelength range where the dilute nitride active material experiences maximum gain. As an example, the performances of the switch under electrical control are crosstalk
$\hbox{CT} = -14.1\ \hbox{dB}$
, gain in the on-state
${\rm G} = 7.6\ \hbox{dB}$
, and bandwidth
$\Delta\lambda_{-10\,{\rm dB}} = 1.5\ \hbox{nm}$
. By increasing the input power above the optical threshold value of the gain saturation, the switching performance worsens in terms of crosstalk and gain, but the wavelength selectivity improves, since the bandwidth decreases down to
$\Delta\lambda_{-10\,{\rm dB}} = 0.8\ \hbox{nm}$
for the input optical power
${\rm P}_{i} = 20\ \hbox{mW}$
.