Faculty Publications
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Item Simulation of Radio over Fiber System for Microwave Signal Generation using Sub- Carrier Modulation Technique(Institute of Electrical and Electronics Engineers Inc., 2023) Singh, V.; Meena, K.S.R.; Singh, M.Nowadays, Radio over fiber (RoF) technology is used in a variety of applications, including wireless communication systems, satellite communication systems, and radar systems. In this paper, we reported a sub-carrier modulation with Amplitude Shift Keying (SCM-ASK) system which supports the transmission of various signals across a single-mode fibre with enhanced encryption efficiency. The quality of the received signal is usually poor in RoF systems, a number of factors may contribute to this problem, such as high bit error rates (BER), low Q-factor values, and the receiver may not be working in a high data rate network. To overcome this, the Q-factor needs to be raised while BER should be brought down to assured values. Using Opti-System software, SCM-ASK is investigated at various channel spacings and fibre lengths. Also, the RoF system performance is analyzed in terms of BER, Q-factor, and the eye diagram patterns. © 2023 IEEE.Item Microwave Photonics Based Millimeter-Wave Signal Generation Technique for 5G Systems(Institute of Electrical and Electronics Engineers Inc., 2024) Meena, K.S.R.; Singh, M.We report a novel millimeter-wave (mm-wave) signal generation scheme with microwave photonics (MWP) technology for advanced 5G optical links. This work combines two parallel Mach Zehnder modulators with a series Mach Zehnder modulator for better tunability and efficient bandwidth. The experiments confirm a 35-GHz mm-wave signal of highest power and a 60-GHz mm-wave of lowest power from a 15-GHz electrical drive input signal. The optical sideband suppression ratio (OSSR) and the radio frequency sideband suppression ratio (RFSSR) over a 0.5-km standard single-mode fiber link are 27 and 66 dBm, respectively. The harmonic suppression is also studied with modulation depth (m) and filter attenuation (a) parameters. The system s performance is evaluated in terms of eye patterns, quality factor ( Q), output power spectrum, and margin. In addition, the suggested photonic link plays a crucial role in developing 5G communication systems for generating high-frequency, ultrafast speed, and low-noise mm-wave signals © 1963-2012 IEEE.Item Phase Noise Reduction in Optoelectronic Oscillator With Quadratic Fiber Bragg Grating Dispersion Engineering(Institute of Electrical and Electronics Engineers Inc., 2025) Renuka, B.; Singh, M.This article presents the design, implementation, and performance analysis of an optoelectronic oscillator (OEO) incorporating a quadratic fiber Bragg grating (Q-FBG). Integrating Q-FBG in OEO architecture introduces enhanced filtering capabilities and precise frequency control, which are critical for applications requiring high stability and low phase noise. It provides a tailored reflection spectrum, enabling improved mode selection and reduced spurious tones. Experiments confirm oscillator’s superior performance metrics, including phase noise reduction and frequency stability. Theoretical modeling and simulation corroborate the experimental results, confirming the Q-FBG’s effectiveness in optimizing OEO performance. An error vector magnitude (EVM) of 2.5% is obtained for the generated signal, indicating high quality and improved modulation accuracy of the microwave signal. The uncertainty of measurement, particularly the standard deviation in EVM values, is analyzed to assess system reliability. The potential applications of the proposed OEO include telecommunications, radar systems, and precision measurement instruments. The study underscores the significant advantages of incorporating Q-FBG in OEOs and paves the way for further advancements in microwave photonics technology. © 1963-2012 IEEE.Item Widely-tunable optoelectronic oscillator using a microfiber coupler Sagnac loop(Springer, 2025) Meena, K.S.R.; Thayaba Nausheen, A.; Singh, M.An optoelectronic oscillator (OEO) integrating a Microfiber Coupler Sagnac loop and a parallel optical amplifier is proposed for the generation of wide-range, stable microwave signals. Unlike conventional OEOs that rely on dual-loop configurations, fixed optical delay lines, or bulky and lossy external filters, our design offers a solution capable of generating RF signals over a broad frequency range of 5–20 GHz. Sagnac loop provides high-resolution spectral filtering and substantial side-mode suppression, while the parallel optical amplifier enhances the loop gain and facilitates the stable oscillation across the entire tuning bandwidth. Our results confirm multi-tone microwave signal generation with a side-mode suppression ratio exceeding 50 dB. The single sideband phase noise of about ? 125 dBc/Hz at 10 kHz offset frequency is achieved for 10 GHz oscillation frequency. This hybrid architecture leads to highly stable, tunable, and pure microwave signal generation, making it suitable for radar systems, high-speed communication, and advanced sensing applications. © The Author(s), under exclusive licence to The Optical Society of India 2025.Item Microwave photonic signal generation using a quadratic FBG based optoelectronic oscillator(Institute of Physics, 2025) Renuka, B.; Shivaputra, A.; Ramesh, S.; Mandi, M.V.; Meena, M.; Singh, M.We proposed an optoelectronic oscillator (OEO), incorporating a dual parallel Mach-Zehnder modulator (DP-MZM) and quadratic fiber Bragg grating (Q-FBG) for microwave photonic (MWP) applications. The suggested system combines the unique dispersive and reflective properties of the Q-FBG to achieve enhanced frequency stability and spectral purity. The Q-FBG facilitates precise control over the oscillation frequency by introducing quadratic phase modulation, effectively suppressing spurious modes and improving phase noise performance. Experimental results demonstrate the capability of the OEO-QFBG system to generate low-phase-noise microwave signals with superior stability compared to conventional OEO designs. A 20 GHz microwave signal with low phase noise of -134.93 dBc Hz?1 at 10 kHz offset was generated. This work underscores the potential of integrating advanced photonic components, such as Q-FBGs, for advanced microwave photonics applications, including radar systems, communications, and high-precision instrumentation. © 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.