A new amplifying technique for weak and noisy signals
Date:
February 2, 2022
Source:
Institut national de la recherche scientifique - INRS
Summary:
Scientists have demonstrated a technique for the recovery of weak,
noise- dominated optical signals.
FULL STORY ==========================================================================
Weak optical signals are common in many science and technology
applications.
However, they are difficult to detect or process due to the incoherent
noise that is inherently present in any system. PhD student Benjamin
Crockett and colleagues, working under the supervision of Professor Jose' Azan~a of the Institut national de la recherche scientifique (INRS),
have demonstrated a technique for the recovery of weak, noise-dominated
optical signals. Their research was published in the journal Optica.
==========================================================================
This achievement is relevant to various fields like telecommunications, bioimaging and remote sensing. For example, there is considerable loss
from long-distance propagation through the optical fibre. In light-based biomedical imaging applications, there are limitations for the light power
to avoid damaging the living tissue. Similarly, in lidar applications
(laser remote sensing), high optical powers can pose a threat to the eyes
of a passerby. In all these cases, the recovery of weak, noise-dominated signals remains a key challenge.
Lasers have enabled tremendous advances in so many fields of research. Yet
the problem of sensitivity and noise eventually leads to an obstacle
for further development.
" We hope that this technique could be used by researchers around the
world to access previously unattainable information contained in weak,
noisy signals." The work, conducted in collaboration with Montreal-based telecommunications company Fonex Data Systems Inc., is of potential
immediate practical interest in industry.
An innovative approach Most common approaches are ill suited to retrieve
a weak signal because they either further attenuate the signal or inject further amount of noise. The new method developed by the researchers
uses passive amplification of the signal of interest over the noise,
enabling access to signals that could not be recovered otherwise. No
other technique simultaneously increases the energy of the signal of
interest while reducing its relative noise content.
==========================================================================
To achieve this, the researchers exploit the Talbot self-imaging effect,
which is observed when a periodic train of pulses propagates through a dispersive medium such as an optical fiber. It causes different frequency components of light (i.e., the different "colors" of light) to travel
at different speeds.
The Talbot effect was previously utilized to coherently "stack" or
combine consecutive pulses in the incoming train, leading to a passive amplification of the pulses' peak power.
Applications with arbitrary signals In the work reported in Optica, the
INRS researchers were able to extend this technique to achieve passive amplification of any given arbitrary signal, without a requirement
for periodicity.
"We realized that we could find a particular arrangement so that the
Talbot effect could be used to amplify aperiodic signals, which is to
say, virtually any of the signals found in these different practical
fields." says Professor Azan~a.
Just like a physical lens can be used to focus a weak and large image
into a narrower and more intense beam, the proposed system can be used to redistribute the energy of a weak signal into a series of high intensity pulses. This power focusing effect can be achieved without distorting
the signal shape (i.e., carried information) and without increasing the
noise along the signal.
The researchers believe this discovery opens many avenues for upcoming
research lines. It could be possible to also adapt this technique for
2D or 3D spatial images, a feat that may have important applications in astronomy research, photography or holography, among others. Furthermore,
while the present demonstration focused on optical waveforms, such as
the ones used in telecommunications, this technique could be adapted for different types of waves, including radio, microwave, plasma, acoustic
or even quantum waves.
========================================================================== Story Source: Materials provided by Institut_national_de_la_recherche_scientifique_-_INRS.
Original written by Audrey-Maude Vezina. Note: Content may be edited
for style and length.
========================================================================== Journal Reference:
1. Benjamin Crockett, Luis Romero Corte's, Reza Maram, Jose'
Azan~a. Optical
signal denoising through temporal passive amplification. Optica,
2022; 9 (1): 130 DOI: 10.1364/OPTICA.428727 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/02/220202111750.htm
--- up 8 weeks, 4 days, 7 hours, 13 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)