A5030427810- Optical Network Technologies
- Advanced Photonic Communication Systems
- Photonic and Optical Devices
- Advanced Optical Sensing Technologies
- Advanced Fiber Laser Technologies
- Optical Coherence Tomography Applications
- Spectroscopy and Laser Applications
- Terahertz technology and applications
- Semiconductor Lasers and Optical Devices
- Power System Optimization and Stability
- Advancements in PLL and VCO Technologies
- Nuclear Engineering Thermal-Hydraulics
- Photonic Crystal and Fiber Optics
- Spectroscopy and Quantum Chemical Studies
- Model Reduction and Neural Networks
- Advanced Measurement and Metrology Techniques
- Advanced Optical Network Technologies
University College London
2019-2023
University College Lahore
2021
Nanjing Forestry University
2016
The maximum data throughput in a single mode optical fibre is function of both the signal bandwidth and wavelength-dependent signal-to-noise ratio (SNR). In this paper, we investigate use hybrid discrete Raman & rare-earth doped amplifiers to enable wide-band gain, without spectral gaps between amplification bands. We describe widest continuous coherent transmission experimentally demonstrated date 16.83 THz, achieved by simultaneously using S-, C- L-bands. variation parameters over...
Broadband spectra of 20 L-amino acids were obtained at room temperature by terahertz time-domain and infrared spectroscopy. The intensity absorption peaks varied with the concentrations amino acids, optimum proportion for each acid was obtained. An spectral database established from 0 to 6 THz. associations between molecular structures analyzed. L-alanine compared calculated results based on density functional theory using two basis sets that reliably consistent.
A pilot-based adaptive equalizer is investigated for high cardinality polarization-division-multiplexing quadrature amplitude modulation transmission systems. Pilot symbols are periodically inserted joint estimation of the dynamic state polarization (SOP) and carrier phase, in a least mean square (LMS) sense. Compared to decision-directed (DDLMS) equalization radially-directed equalization, proposed can achieve robust phase estimation, especially low optical signal-to-noise ratio (OSNR)...
There is increasing interest in low-complexity coherent optical transceivers for the use short-reach fiber links.Amongst simplest configurations heterodyne receiver, using a 3-dB coupler to combine signal with local oscillator (LO) laser output, and single photodiode detection of each polarization.In this paper, through numerical simulations, we investigate impact signal-signal beating interference (SSBI) LO relative intensity noise (RIN) on performance such transceivers.We assess two...
In this paper, we investigate two categories of linear frequency-modulated chirp signals suitable for single-photodiode based coherent light detection and ranging (LiDAR) systems, namely, the continuous-wave (FMCW) single-sideband (SSB) signal amplitude-modulated double-sideband (DSB) signal, compare their achievable receiver sensitivity performance. The DSB requires a simpler transmitter design, as it is real-valued can be generated using single-drive Mach-Zehnder modulator (MZM), while SSB...
Performance for optical fibre transmissions can be improved by digitally reversing the channel environment. When this is achieved simulating short segment separating chromatic dispersion and Kerr nonlinearity, known as digital back-propagation (DBP). Time-domain DBP has potential to decrease complexity with respect frequency domain algorithms. However, when using finer step in algorithm, accuracy of individual smaller steps suffers. By adapting filters simulated or measured data problem...
Recently, we demonstrated a record single-mode fibre net throughput of 178.08 Tbit/s. In this paper, model experiment, investigating the main limitations and challenges behind total throughput, together with details some approaches to overcome them, an outlook for future ultra-wideband network design optimisation.
A frequency-domain multiple-input multiple-output (FD-MIMO) equalizer employing a momentum-based gradient descent update algorithm is proposed for polarization multiplexing coherent receivers. Its performance in operation with dynamically varying optical channels investigated and the impact of filter delays, arising from latency fast Fourier transforms (FFTs) other digital signal processing (DSP) operations feedback loop, assessed. We show that used to control response has significantly...
We study the impact of laser phase noise on ranging precision in a frequency-modulated continuous-wave (FMCW) LiDAR system, demonstrating 384.72 m with ~ 15 cm at 7 × intrinsic coherence length.
Low-complexity transceivers offering high spectral efficiency and dispersion tolerance will be required for short-haul links operating at 100 Gb/s per wavelength beyond. Recent developments in self-coherent are described future research directions suggested.
In this paper, we employed a temperature-tuned terahertz time domain spectroscopy (THz-TDS) to measure THz spectroscopic features of four amino acids, i.e., L-alanine, L-asparagine, L-cysteine and L-tyrosine in the temperature range 4.5-300K. The spectra acids were found be sensitive change. All have blue-shift phenomenon with about 0.10 during cooling process, common new absorption peak at 0.20 appears below 100 K for L-asparagine L-cysteine. measured transmission compared results simulated...
We present the first experimental demonstration of learned time-domain digital back-propagation (DBP), in 64-GBd dual-polarization 64-QAM signal transmission over 1014 km. Performance gains were comparable to those obtained with conventional, higher complexity, frequency-domain DBP.
We study the impact of laser phase noise on ranging precision in a frequency-modulated continuous-wave (FMCW) LiDAR system, demonstrating 384.72 m with ∼15 cm at 7× intrinsic coherence length.