Composite Triple Beat Research Articles

Computationally efficient composite triple beat cancellation for DML-based DA-RoF fronthaul.

The digital-analog radio-over-fiber (DA-RoF) scheme offers a high-fidelity and spectrally efficient solution for future mobile fronthaul. However, to be implemented in the low-cost directly modulated laser with direct detection (DML-DD) link, both the digital and analog parts in DA-RoF modulation would suffer from the composite second-order (CSO) and composite triple beat (CTB) caused by the chirp-dispersion interaction. In this Letter, we propose and experimentally demonstrate a computationally efficient composite triple beat cancellation (CTB-C) algorithm for DA-RoF fronthaul in the dispersion-uncompensated C-band DML-DD link. The CSO and CTB are suppressed at the receiver-side DSP based on the theoretical model of these nonlinear distortions. In the proof-of-concept experiment, a 1.2-dB improvement in the recovered signal-to-noise ratio (SNR) is obtained with 5.5-GHz 1024-QAM orthogonal frequency division multiplexing (OFDM) signal after 10-km standard single-mode fiber (SSMF) transmission. The proposed CTB-C technique does not require the training process and performs close to the Volterra-based feed-forward equalizer (VFE) under the complexity constraint.

Bidirectional hybrid OFDM based free-space/wireless-over-fiber transport system

We propose and demonstrate a successful application of orthogonal frequency division multiplexing (OFDM), reflective semiconductor optical amplifier and polarization multiplexing techniques to facilitate bidirectional hybrid OFDM based integrated free-space optics and wireless transport system. The downlink 12 Gbps OFDM data-stream and 79 community antenna television (CATV) channels are transmitted over 50 km single mode fiber (SMF) as well as 12 m and 10 m free-space link, respectively. The uplink 10 Gbps/5 GHz and 5 Gbps/3.5 GHz OFDM data streams are communicated over separate 50 km SMF along with 8 m wireless links. We have used 32-quadrature amplitude modulation (QAM) and 16-QAM modulation formats for downlink and uplink, correspondingly. The performance of the system is observed by evaluating carrier-to-noise ratio (CNR), composite second-order (CSO) and composite-triple-beat (CTB) for the CATV signal, and constellations diagrams, bit error rate (BER), signal-to-noise ratio (SNR), and error vector magnitude (EVM) values for the OFDM signals. After transmission over 50 km SMF as well as 10 m free-space, the resulting CNR, CSO and CTB values are > 51 dB, 23.3 dB, respectively. 4 dBm and 3.2 dBm power penalties at BER of $$10^{ - 8}$$, below 13% EVM and > 21.3 dB/ > 22.2 dB SNR values are observed for the uplink 10 Gbps/5 GHz and the 5 Gbps/3.5 GHz OFDM data signals, respectively, over 50 km SMF as well as 8 m wireless is observed.

320 Channel Optically Amplified 1550 nm Light wave Directly Modulated CATV Transport System Performance Improvement Using Optical Injection Technique

This paper proposed and successfully demonstrated 320 channel optically amplified 1550 nm light wave directly modulated high channel density CATV transport system. The optical injection technique increases the photon density of the modulation section and improves the overall performance of the fiber optical CATV system. Designed network demonstrates the improvement of transmission distance and channel density. Good performance in terms of output power, Composite Triple Beat (CTB), Signal to Noise Ratio (SNR), Composite Second Order (CSO) and Carrier to Noise ratio (CNR) has been observed by utilizing optical injection technique. Almost about 74 dBm Composite Second Order (CSO) has been achieved by utilizing 14 dBm optical injection techniques.

Third‐order non‐linearity reduction in a bidirectional CATV/RoF hybrid transmission system using incoherent light injection and RF amplifier pre‐distortion

We propose and experimentally demonstrate a bidirectional Community Antenna Television/radio-over-fibre (RoF) hybrid transmission system based on incoherent light injection and RF amplifier pre-distortion to reduce third-order non-linearity. At downlink, 10-Gbps/30-GHz data and 79 CATV channels are transmitted over 50 km single-mode fibre (SMF), and at uplink 5-Gbps/15-GHz data and CATV signals are successfully transmitted concurrently over 50 km through the same SMF. The authors have found low bit-error rate (BER) and clear eye diagrams for the RoF data signals, and obtained outstanding transmission performance in terms of carrier-to-noise ratio, composite second order, and composite triple-beat for the CATV signals in downlink and uplink transmission.

Two-way lightwave transmission system with a centralized-light-source and VCSEL-based upstream wavelength selector

A lightwave transmission system employing a centralized-light-source and vertical-cavity surface-emitting laser (VCSEL)-based upstream wavelength selector in two-way transmission is proposed and successfully demonstrated. The transmission performances of cable television (CATV), millimeter-wave (MMW), and baseband (BB) signals are investigated in a bidirectional way, with the assistance of the centralized-light-source and VCSEL-based upstream wavelength selector on the transmitter side. Extra optical components, such as a reflective semiconductor optical amplifier (RSOA), Fabry-Perot laser diode (FP LD), and phase modulator (PM), and the elaborated injection-locked technique are not required for upstream modulation, which largely reduce the cost and complication of two-way lightwave transmission systems. Excellent transmission performances of the carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) are obtained over a 25-km single-mode fiber (SMF) transmission with 100-m free-space link/5-m RF wireless transmission. This proposed two-way lightwave transmission system shows a convenient and economic eminent structure.

Optimum parameters controlling distortion and noise of semiconductor laser under analog multichannel modulation

This paper presents a comprehensive modelling and simulation study on the optimum parameters that control the distortion and noise of semiconductor lasers (SLs) subject to multichannel modulation for use in analog cable television (CATV) fibre links. The study is based on numerical integration of the rate equation model of the semiconductor laser. The parameters comprise the modulation index per channel (m / ch), number of loaded channels (N) and fibre length $$(L_{F})$$ . The signal distortions include the composite second-order (CSO) and composite triple beat (CTB) distortions. The noise is assessed in terms of the relative intensity noise (RIN) and carrier-to-noise ratio (CNR). In order to achieve acceptable CNR values for SL, m / ch should be less than 7.5 and 2% when loading 12 and 80 channels, respectively. For the CATV fibre link with $$L_{F} = 10 \hbox { km}$$ , the increase in the number of channels from 12 to 80 corresponds to lowering the optimum value of m / ch from 7 to 1%. The increase of $$L_{F}$$ to 50 km limits the optimum value of m / ch between 1.4 and 1%, which corresponds to loading between 12 and 17 channels only.

Based on FP LDs with split band technique in two-channel fiber optical CATV transport system

This study proposes a two-channel fiber optic cable television (CATV) transport system based on Fabry–Perot laser diodes (FP-LDs) with a split band technique. To reduce the interference between channels, we apply the split band technique to two channels with different frequencies by using two converters at each moment. In this two-channel transmission scheme, composite second-order (CSO) and composite triple-beat (CTB) distortions induced by the systems are possibly confined in unused channels and result in good transmission performances. Through a 40 km standard single-mode fiber transmission, excellent performances of carrier-to-noise ratio (≥50 dB), CSO (≥70 dB), and CTB (≥72 dB) are obtained using the proposed fiber optic CATV transport systems. The proposed systems employing FP-LDs with a split band technique are also simpler and more cost effective than conventional externally modulated systems.

Bidirectional fiber-IVLLC and fiber-wireless convergence system with two orthogonally polarized optical sidebands.

A bidirectional fiber-invisible laser light communication (IVLLC) and fiber-wireless convergence system with two orthogonally polarized optical sidebands for hybrid cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission is proposed and experimentally demonstrated. Two optical sidebands generated by a 60-GHz MMW signal are orthogonally polarized and separated into different polarizations. These orthogonally polarized optical sidebands are delivered over a 40-km single-mode fiber (SMF) transport to effectually reduce the fiber dispersion induced by a 40-km SMF transmission and the distortion caused by the parallel polarized optical sidebands. To the best of our knowledge, this work is the first to adopt two orthogonally polarized optical sidebands in a bidirectional fiber-IVLLC and fiber-wireless convergence system to reduce fiber dispersion and distortion effectually. Good carrier-to-noise ratio, composite second order, composite triple beat, and bit error rate (BER) are achieved for downlink transmission at a 40-km SMF operation and a 100-m free-space optical (FSO) link/3-m RF wireless transmission. For up-link transmission, good BER performance is acquired over a 40-km SMF transport and a 100-m FSO link. The approach presented in this work signifies the advancements in the convergence of SMF-based backbone and optical/RF wireless-based feeder.

A Bidirectional Fiber-Wireless and Fiber-IVLLC Convergence System with a Dual-Polarization Modulation Scheme and an MZM-OEO-Based BLS

A bidirectional fiber-wireless and fiber-invisible laser light communication (IVLLC) convergence system that adopts a dual-polarization modulation scheme and a Mach–Zehnder modulator (MZM)-optoelectronic oscillator (OEO)-based broadband light source (BLS) for hybrid cable television (CATV)/microwave (MW)/millimeter-wave (MMW)/baseband signal transmission is proposed and experimentally demonstrated. The MZM employed in the MZM-OEO is operated at the minimum transmission point, which results in the format of optical carrier suppression for the y -axis component of the light. Using a dual-polarization modulation scheme, the optical carrier modulated with CATV signal ( x -polarization) and the optical sidebands modulated with MW and MMW data signals ( y -polarization) are separated and polarized orthogonally automatically. Through an in-depth observation, good carrier-to-noise ratio, composite second-order, composite triple-beat, and bit error rate performances are obtained over a 40-km single-mode fiber and a 10-m RF/100-m optical wireless transport. Such a bidirectional fiber-wireless and fiber-IVLLC convergence system is a notable option; it would be attractive for providing broadband heterogeneous services such as CATV, Internet, and big data services.

Bidirectional fiber-wireless and fiber-IVLLC integrated system based on polarization-orthogonal modulation scheme.

A bidirectional fiber-wireless and fiber-invisible laser light communication (IVLLC) integrated system that employs polarization-orthogonal modulation scheme for hybrid cable television (CATV)/microwave (MW)/millimeter-wave (MMW)/baseband (BB) signal transmission is proposed and demonstrated. To our knowledge, it is the first one that adopts a polarization-orthogonal modulation scheme in a bidirectional fiber-wireless and fiber-IVLLC integrated system with hybrid CATV/MW/MMW/BB signal. For downlink transmission, carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) perform well over 40-km single-mode fiber (SMF) and 10-m RF/50-m optical wireless transport scenarios. For uplink transmission, good BER performance is obtained over 40-km SMF and 50-m optical wireless transport scenario. Such a bidirectional fiber-wireless and fiber-IVLLC integrated system for hybrid CATV/MW/MMW/BB signal transmission will be an attractive alternative for providing broadband integrated services, including CATV, Internet, and telecommunication services. It is shown to be a prominent one to present the advancements for the convergence of fiber backbone and RF/optical wireless feeder.

A hybrid lightwave transport system based on a BLS with an OSNR enhancement scheme

A hybrid lightwave transport system based on a broadband light source (BLS) with an optical signal-to-noise ratio (OSNR) enhancement scheme for millimeter-wave (MMW)/radio-over-fiber (RoF)/cable television (CATV) signal transmission is proposed and experimentally demonstrated. Unlike traditional hybrid lightwave transport systems for signal transmission, in which a transmitting site needs multiple wavelength-selected distributed feedback laser diodes (DFB LDs) to support various services, such proposed systems employ a phase modulator to provide multiple optical carriers for various applications. Over an 80 km single-mode fiber (SMF) transmission, the bit error rate (BER)/carrier-to-noise ratio (CNR)/composite second-order (CSO)/composite triple-beat (CTB) perform brilliantly for hybrid 100 GHz MMW/50 GHz MMW/10 GHz RoF/550 MHz CATV signal transmission. Such a hybrid lightwave transport system would be attractive for fiber trunk applications to provide broadband integrated services.

A hybrid lightwave transmission system based on light injection/optoelectronic feedback techniques and fiber-VLLC integration

A hybrid lightwave transmission system based on light injection/optoelectronic feedback techniques and fiber-visible laser light communication (VLLC) integration is proposed and experimentally demonstrated. To be the first one of its kind in employing light injection and optoelectronic feedback techniques in a fiber-VLLC integration lightwave transmission system, the light is successfully directly modulated with Community Access Television (CATV), 16-QAM, and 16-QAM-OFDM signals. Over a 40 km SMF and a 10 m free-space VLLC transport, good performances of carrier-to-noise ratio (CNR)/composite second-order (CSO)/composite triple-beat (CTB)/bit error rate (BER) are achieved for CATV/16-QAM/16-QAM-OFDM signals transmission. Such a hybrid lightwave transmission system would be very useful since it can provide broadband integrated services including CATV, Internet, and telecommunication services over both distribute fiber and in-building networks.

Progressive and Cost-Effective Bidirectional CATV/Wireless-Over-Fiber Lightwave Transport System

A progressive bidirectional cable television (CATV)/wireless-over-fiber lightwave transmission system based on one broadband light source (BLS), one arrayed waveguide grating, two intensity modulators, and one phase modulator is proposed and experimentally demonstrated. A continuous amplified spontaneous emission BLS is split into eight channels in the C-band with 50-GHz spacing. The multiple equal-space optical spectra exhibit a high optical signal-to-noise ratio (≥ 55 dB) and good flatness (≤ 5 dB). A high-quality comb multicarrier provides a single wavelength and twin millimeter-wave bands for baseband CATV and wireless transport systems. Several measured values (carrier-to-noise ratio ≥ 64 dB, composite second order ≥ 62 dB, composite triple beat ≥ 63 dB, and bit error rate $\leq 10^{-9} $ ) can be obtained from distortion-reduced and noise-free performance. Moreover, downstream and upstream high-bit-rate wireless transmissions exhibit an interference-eliminating property. Thus, the proposed system does not only offer a future for progressive fiber backbone and CATV/wireless hybrid networks, but also provides a full-duplex interference-free for high-data-rate mobile communication and in-home CATV access networks as well.

Hybrid CATV/MMW/BB lightwave transmission system based on fiber-wired/fiber-wireless/fiber-VLLC integrations.

A hybrid lightwave transmission system for cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission based on fiber-wired/fiber-wireless/fiber-visible laser light communication (VLLC) integrations is proposed and demonstrated. For down-link transmission, the light is intensity-modulated with 50-550 MHz CATV signal and optically promoted from 25 GHz radio frequency (RF) signal to 10 Gbps/50 GHz and 20 Gbps/100 GHz MMW data signals based on fiber-wired and fiber-wireless integrations. Good performances of carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) are obtained over a 40-km single-mode fiber (SMF) and a 10-m RF wireless transport. For up-link transmission, the light is successfully intensity-remodulated with 5-Gbps BB data stream based on fiber-VLLC integration. Good BER performance is achieved over a 40-km SMF and a 10-m free-space VLLC transport. Such a hybrid CATV/MMW/BB lightwave transmission system is an attractive alternative, it gives the benefits of a communication link for broader bandwidth and higher transmission rate.

A Bidirectional Hybrid Lightwave Transport System Based on Fiber-IVLLC and Fiber-VLLC Convergences

This paper proposes and validates a bidirectional hybrid lightwave transport system based on fiber-invisible laser light communication (IVLLC) and fiber-visible laser light communication (VLLC) convergences with light injection and optoelectronic feedback techniques. This paper is also the first to employ light injection and optoelectronic feedback techniques in a bidirectional lightwave transport system based on fiber-IVLLC and fiber-VLLC integration. Light is successfully modulated directly with cable television (CATV), 16-quadrature amplitude modulation (QAM), and 16-QAM-orthogonal frequency-division multiplexing (OFDM) signals. Good carrier-to-noise ratio, composite second order, composite triple beat, and bit error rate (BER) are obtained for CATV, 16-QAM, and 16-QAM-OFDM signal transmissions over a combined 40-km single-mode fiber, a 1.43-km photonic crystal fiber, and 6-m free-space transmission. The proposed bidirectional hybrid lightwave transport system exhibits significant potential in providing broadband integrated services, such as CATV, Internet, and telecommunication, via optical fiber and free-space indoor networks.

Hybrid wireless-over-fiber transmission system based on multiple injection-locked FP LDs.

A hybrid wireless-over-fiber (WoF) transmission system based on multiple injection-locked Fabry-Perot laser diodes (FP LDs) is proposed and experimentally demonstrated. Unlike the traditional hybrid WoF transmission systems that require multiple distributed feedback (DFB) LDs to support different kinds of services, the proposed system employs multiple injection-locked FP LDs to provide different kinds of applications. Such a hybrid WoF transmission system delivers downstream intensity-modulated 20-GHz microwave (MW)/60-GHz millimeter-wave (MMW)/550-MHz cable television (CATV) signals and upstream phase-remodulated 20-GHz MW signal. Excellent bit error rate (BER), carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple-beat (CTB) are observed over a 40-km single-mode fiber (SMF) and a 4-m radio frequency (RF) wireless transport. Such a hybrid WoF transmission system has practical applications for fiber-wireless convergence to provide broadband integrated services, including telecommunication, data communication, and CATV services.

A full-duplex CATV/wireless-over-fiber lightwave transmission system.

A full-duplex CATV/wireless-over-fiber lightwave transmission system consisting of one broadband light source (BLS), two optical interleavers (ILs), one intensity modulator, and one phase modulator is proposed and experimentally demonstrated. The downstream light is optically promoted from 10Gbps/25GHz microwave (MW) data signal to 10Gbps/100GHz and 10Gbps/50GHz millimeter-wave (MMW) data signals in fiber-wireless convergence, and intensity-modulated with 50-550 MHz CATV signal. For up-link transmission, the downstream light is phase-remodulated with 10Gbps/25GHz MW data signal in fiber-wireless convergence. Over a 40-km single-mode fiber (SMF) and a 10-m radio frequency (RF) wireless transport, bit error rate (BER), carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple-beat (CTB) are observed to perform well in such full-duplex CATV/wireless-over-fiber lightwave transmission systems. This full-duplex 100-GHz/50-GHz/25-GHz/550-MHz lightwave transmission system is an attractive alternative. This transmission system not only presents its advancement in the integration of fiber backbone and CATV/wireless feeder networks, but also it provides the advantages of a communication channel for higher data rates and bandwidth.

Hybrid CATV/16-QAM-Digital CATV/16-QAM-OFDM in-building network over passive optical network and gradient index-plastic optical fiber/visible light communication transport

We propose and experimentally demonstrate a hybrid CATV/16-QAM-Digital CATV/16-QAM-OFDM in-building network over a 40-km single-mode fiber and graded index-plastic optical fiber/10-m visible light communication. The application of external injection technology with the addition of an optoelectronic feedback that raises the resonance frequency of the laser diode results in increased system transmission capability. Good performances of carrier-to-noise ratio, composite second-order, and composite triple-beat are obtained for the CATV signal. A low bit-error-rate value is achieved for the 16-QAM-Digital CATV/16-QAM-OFDM signal.

A Hybrid CATV/16-QAM-OFDM In-House Network Over SMF and GI-POF/VLC Transport

This letter proposes and experimentally demonstrates a hybrid cable television (CATV)/16-quadrature amplitude modulation (QAM)-orthogonal frequency-division multiplexing (OFDM) in-house network over a combined 40 km single-mode fiber, 1.43 km photonic crystal fiber, and 30 m graded index-plastic optical fiber/5 m visible light communication transport. Good performances of carrier-to-noise ratio, composite second-order, and composite triple-beat are obtained for the CATV signal. A low bit error rate value is achieved for the 16-QAM-OFDM signal.

Broadband Distortion Cancellation Technique in GaAs HJFET and GaN FET Cascode Amplifier

This paper describes broadband distortion cancellation technique in the cascode configuration composed of GaAs heterojunction field-effect transistor (HJFET) for the first stage and AlGaN/GaN heterojunction FET (HJFET), for the final stage to realize broadband low-distortion cable television (CATV) power amplifier. The device structures of GaAs HJFET and GaN FET were optimized using the Volterra distortion analysis on a load-line. The transconductance gm-profile on a load-line of the first-stage GaAs HJFET was designed to obtain the gain expansion at near Class-A operation to cancel the gain compression of the final-stage GaN FET. The gate-orientation of GaAs HJFET was optimized to achieve low distortion at lower current condition. The field-plate electrode structure of the final-stage GaN FET was optimized to improve the high-frequency distortion characteristics by reducing the capacitance nonlinearity on a load-line. The developed CATV power amplifier demonstrated low composite triple beat characteristics less than -72 dBc at low drain current condition of 380 mA under 53.7 dBmV at 865 MHz, 11.7-dB tilt, and 132 channels.