Ultra-wideband signal acquisition by use of channel-
interleaved photonic analog-to-digital converter under
the assistance of dilated fully convolutional network
Rui Wang (汪 锐), Shaofu Xu (徐绍夫), Jianping Chen (陈建平),
and Weiwen Zou (邹卫文)*
State Key Laboratory of Advanced Optical Communication Systems and Networks, Intelligent Microwave Lightwave
Integration Innovation Center (iMLic), Department of Electronic Engineering, Shanghai Jiao Tong University,
Shanghai 200240, China
*Corresponding author: wzou@sjtu.edu.cn
Received June 28, 2020; accepted August 11, 2020; posted online September 28, 2020
We demonstrate a photonic architecture to enable the separation of ultra-wideband signals. The architecture
consists of a channel-interleaved photonic analog-to-digital converter (PADC) and a dilated fully convolutional
network (DFCN). The aim of the PADC is to perform ultra-wideband signal acquisition, which introduces the
mixing of signals between different frequency bands. To alleviate the interference among wideband signals, the
DFCN is applied to reconstruct the waveform of the target signal from the ultra-wideband mixed signals in
the time domain. The channel-interleaved PADC provides a wide spectrum reception capability. Relying on
the DFCN reconstruction algorithm, the ultra-wideband signals, which are originally mixed up, are effectively
separated. Additionally, experimental results show that the DFCN reconstruction algorithm improves the
average bit error rate by nearly three orders of magnitude compared with that without the algorithm.
Keywords: ultra-wideband signal acquisition; photonic analog-to-digital converter; deep learning.
doi: 10.3788/COL202018.123901.
A wide operating frequency range and sufficient instanta-
neous receiving bandwidth are indispensable for signal re-
connaissance, which is one of the key technologies of
electronic warfare (EW)
[1,2]
. Conventional reconnaissance
equipment is faced with a great challenge with the devel-
opment of modern electronic information technology. The
introduction of photonic technology provides a new idea
for the research and development of reconnaissance equip-
ment. A photonic analog-to-digital converter (PADC)
combines the advantages of the optical front end, namely
high speed, low jitter, and wide bandwidth, with the char-
acteristic of high accuracy of the electronic back end.
Thus, it improves system performance and provides an
ideal solution for the next-generation information sys-
tems
[3–8]
. Especially in recent years, channel-interleaved
PADCs have made tremendous breakthroughs
[9–12]
.
PADC-based systems are of wide receiving bandwidth,
which also brings about issues such as more complexity in
received signals and severe interfere nce among signals. In
this sense, the difficulty of analyzing signals increases, es-
pecially when the spectrum of signals is aliased. In order to
avoid the influence of interference between signals and ac-
curately extract the signal that we are interested in from
the mixture containing multiple signals, the problem is
regarded as a single channel blind source separation
(SCBSS)
[13]
, of which the purpose is to restore the original
source signal from one sensor throu gh various means. To
effectively achieve SCBSS, different methods based on
hand-crafted algorithms are reported
[14–16]
. Recently, deep
learning
[17]
has achieved outstanding performance in
medical imaging, communication, speech enhancement,
and image processing
[18–21]
. By introducing deep learning
technology into the traditional processing syste ms, supe-
rior performance is expected and demonstrated, such as
combining optical microscopy with a generative adversa-
rial network (GAN) to achieve super-resolution under a
large field of view
[22]
, combining microscope hardware with
deep learning to offer accurate image classification
[23]
, and
using a residual-on-residual learning model to realize lin-
earization and mismatch compensation in PADC
[10]
.
In this Letter, a channel-interleaved PADC is seam-
lessly combined with a dilated fully convolutional network
(DFCN), which are two essential parts for ultra-wideband
signals acquisition. The bandwidth advantage of the
PADC is exploited to obta in ultra-wideband signals with
a wide operating frequency range and sufficient instanta-
neous receiving bandwidth [tens of gigahertz (GHz)]. The
DFCN successfully separates the target signal from the
mixture with high fidelity, lowering the interference
among aliased signals. To demonstrate the feasibility of
the proposal, several categories of microwave signals are
experimentally conducted and separated. Additionally,
we implement the signal separation for digitally modu-
lated signals. Experimental results show that our scheme
can accurately separate the digital signal under the inter-
ference of microwave signals. The average bit error rate
(BER) has been improved by about three orders of mag-
nitude after separation of the digital signal.
Figure
1 shows the model for ultra-wideband signals ac-
quisition and separation, which is mainly composed of two
COL 18(12), 123901(2020) CHINESE OPTICS LETTERS December 2020
1671-7694/2020/123901(6) 123901-1 © 2020 Chinese Optics Letters