Optical bistable devices as sensing elements

Abstract

The nonlinear optical properties of many materials and devices have been the main object of research as potential candidates for sensing in different places. Just one of these properties has been, in most of the cases, the basis for the sensing operation. As a consequence, just one parameter can be detected. In this paper, although just one property will be employed too, we will show the possibility to sense different parameters with just one type of sensor. The way adopted in this work is the use of the optical bistability obtained from different photonic structures. Because this optical bistability has a strong dependence on many different parameters the possibility to sense different inputs appears. In our case, we will report the use of some non-linear optical devices, mainly Semiconductor Optical Amplifiers, as sensing elements. Because their outputs depend on many parameters, as the incident light wavelength, polarization, intensity and direction, applied voltage and feedback characteristics, they can be employed to detect, at the same time, different type of signals. This is because the way these different signals affect to the sensor response is very different too and appears under a different set of characteristics.

Optical bistability in a one-dimensional photonic crystal resonator using a reverse-biased pn-junction

“…Our experimental studies show that the photocarriers are induced mainly by the linear optical absorption in the device. The proposed approach can be exploited to design ultralow power optical transistors, optical memory elements, and ultrasensitive sensors [19][20][21][22]. In addition to its contribution to heat generation, the photocurrent can be monitored in an external electronic circuit to generate a negative feedback signal (i.e., adjusting the reverse bias voltage) to stabilize the bistable features against the random variations of the environmental conditions (e.g., temperature).…”

Vertical-cavity semiconductor optical amplifiers (VCSOAs) as optical sensing elements

“…Many studies have been done in DFB, and FP-LAS. We have presented some studies on this direction, with difference approaches, that can be found on references [2,[6][7]. Here we concentrate our analysis on the use of VCSOA.…”