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We experimentally demonstrate an effective hybrid equalizer with FFE and truncated Volterra filter for a 50-Gb/s PAM-4 over 50-km SSMF in a DML-based IM/DD system. The results show significant computational complexity savings without performance degradation.
In this paper, we propose a block decision-aided (BL-DA) laser phase noise (LPN) estimation algorithm for coherent optical OFDM (CO-OFDM) systems. The OFDM symbols are divided into several blocks and the LPN estimation and compensation procedure is performed based on the decisions between these blocks. The proposed BL-DA algorithm can be applied for higher LPN estimation while at the same time ensuring...
We propose an accurate laser linewidth estimation technique based on the decision-aided maximum likelihood carrier phase estimator (DA-ML). Its performance is verified in M-ary quadrature amplitude modulation (MQAM) within a wide range of the laser linewidths and SNR values.
We report our recent studies on the use of Neural Networks to process the measured Brillouin gain spectrum (BGS) from Brillouin Optical Time Domain Analyzer (BOTDA) and extract temperature information along fiber under test (FUT). Artificial Neural Network (ANN) is trained with ideal Lorentizian BGS before it is used for temperature extraction. Its performance is evaluated by comparison to conventional...
Vital signs (including breath and heartbeat) monitoring is a key tool in healthcare. Current monitors need invasive electronic sensors attached to user's body, which is inconvenient and uncomfortable. We demonstrate photonic smart health monitoring system based on phase-sensitive optical fiber interferometers. Users simply lie/sleep on a sensor mat embedded with optical fiber interferometers. Breath...
The accurate measurement of total mode coupling in FMFs was achieved by a modified S2 imaging system with electromagnetic interference (EMI) shielding. The measurement accuracy of total discrete and distributed mode coupling was improved by 1.41dB and 2.67dB, respectively.
A novel non-wearable respiration monitoring smart mat structure embedded with optical fiber sensor is proposed and experimentally investigated, which can effectively detect the breathing rate (BR) of human subjects in sleeping position. The sensing principle is mainly based on the Mach-Zehnder interferometer (MZI), and the fibers used are all common single mode fibers (SMFs) with 900-micron buffer...
In this paper, an indoor localization system making use of LEDs, is proposed and demonstrated in the space of 100 cm × 118.5 cm × 128.7 cm. Different LED lamps transmitted signals with different central frequencies and the identities (IDs) of the transmitters are encoded on the envelopes of the transmitted signals. At the receiver side, the finite impulse response (FIR) filters are applied to discriminate...
We experimentally demonstrated an 80-Gb/s PDM-SSB-OFDM transmission over 80km SSMF at C-band using a single photodetector. The two SSB-OFDM signals are placed with the different center frequency to share the guard band. The required OSNRs at 7% overhead HD-FEC threshold are 28.5dB and 29dB for BTB and 80km transmission respectively.
In this paper, we propose to design an ideal location-based zero-forcing equalizer (LB-ZFE) to counteract the multi-path effects in indoor visible light communication systems. The proposed ZFE is assumed to match the line-of-sight signal components perfectly. The analytical signal-to-noise ratios (SNRs) of the output electrical signal with and without the LB-ZFE are derived, respectively. Results...
An ultra-fast sweep-free distributed BOTDA sensor is proposed and experimentally demonstrated employing coherent de-modulation of digital optical frequency comb (DOFC) probe signal. The phase shift of each frequency tone induced during the Stimulated Brillouin Scattering (SBS), corresponding to the Brillouin Phase Spectrum (BPS), is simultaneously measured in a single shot without frequency sweeping...
In this paper, modulation formats of M-ary pulse amplitude modulation (PAM)- and M-ary quadrature amplitude modulation (QAM)-asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) could be recognized autonomously in visible light communication (VLC) systems, by using higher order statistics (HOS). Fourth-order cumulants are applied as the decision criterion and the HOS...
A simple fiber-optic in-line Mach-Zehnder modal interferometer is fabricated and studied for monitoring human being's breathing rate, which is one of the most important vital signs. The sensing structure is simply fabricated by a couple of up-tapers manufactured in the common telecommunication single mode fiber (SMF) by a commercial splicer. Sensing performances with different distances between the...
In this paper, we propose a novel concept of the location-based equalization scheme for indoor visible light communication (VLC) systems. For the first time, indoor VLC can become an indoor visible light positioning based service. Numerical results prove that the proposed scheme is a simple and effective solution to counteract the inter-symbol interference induced by the indoor VLC dispersive channel...
Distributed fiber-optic sensors employ the conventional fiber as the sensing medium and allow all locations along the optical fiber to be measured simultaneously. Thus the sensing scheme provides an efficient way of simultaneously achieving multi-points sensing with a convenient and low-cost configuration. One of the most popular technologies that enables distributed sensing is based on Brillouin...
Simplified Maximum Likelihood (ML) detection and annular-sector (AS) detection for two dimensional constellations is shown to significantly outperform the conventional minimum Euclidean distance (MED) detector in presence of laser phase noise and frequency offset.
This paper proposes to monitor the total accumulated chromatic dispersion (CD) by using extended Kalman filter (EKF) for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) systems. Accurate estimation performance can be achieved by only one OFDM training symbol. Simulations results show that the proposed EKF method can quickly converge to the exact dispersion value within 40 subcarriers...
In this paper, modulation formats of M-ary pulse amplitude modulation (PAM)- and M-ary quadrature amplitude modulation (QAM)-asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) could be recognized autonomously in visible light communication (VLC) systems, by using higher order statistics (HOS). Fourth-order cumulants are applied as the decision criterion and the HOS...
Extraction of temperature distribution using the method of deep neural networks (DNN) for Brillouin optical time domain analyzer (BOTDA) system is demonstrated experimentally. After appropriate training of DNN model, temperature distribution information along the fiber under test could be directly extracted from the experimentally obtained local Brillouin gain spectrums (BGS) using DNN without the...
fast distributed Brillouin optical time domain analyzer (BOTDA) is proposed and experimentally demonstrated based on coherent detection of digital optical frequency comb (DOFC) probe signal. The phase shift of each frequency tone induced by Brillouin interaction, corresponding to the Brillouin Phase Spectrum (BPS), is simultaneously measured in a single data acquisition without averaging process....
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