Optical Single Sideband Signal Research Articles

Photonics-Based Microwave Switching Using Optical Single Sideband Wavelength Conversion in a Semiconductor Optical Amplifier

Photonics-based microwave switching using optical single sideband (OSSB) wavelength conversion in a semiconductor optical amplifier (SOA) is proposed and demonstrated. By using the joint four-wave mixing and self-phase modulation effects in the SOA, the scheme can simultaneously realize the OSSB signal generation and photonic microwave switching, which can minimize the switching crosstalk, since the OSSB signal occupies the least optical bandwidth. This method is also simple as only a single SOA is required. Photonic switching of a 200-Mb/s 16-QAM signal centered at 20 GHz is performed. The signal after switching is an OSSB signal, which has a 22.65- or 17.85-dB sideband suppression ratio for switching based on wavelength down- or up-conversion, respectively. An investigation with the switched signals to combat the dispersion-induced power fading effect for radio over fiber application is also taken. Performance dependence of the optical pump and probe powers, the optical probe-pump power ratio, the modulation depth of the probe signal, and the SOA bias current are also investigated and analyzed.

A novel radio-over-fiber system with dual millimeter-wave signals generated simultaneously

A novel radio-over-fiber (RoF) system with V-band and W-band millimeter-wave (MMW) signals is proposed. We begin our simulation by first utilizing a 20GHz local oscillator (LO) to drive a dual-parallel Mach-Zehnder modulator (DP-MZM) and generate two quadruple-frequency-interval coherent optical carriers. And then we use a dual-drive Mach-Zehnder modulator (DD-MZM) to load signal data and realize an optical single side-band (OSSB) modulation. Following these transmitted signals, we add a 50km single-mode fiber (SMF) for signal transmission and a photonics detector (PD) for signal self-heterodyning detection. Thanking to the mitigated chromatic dispersion (CD) effect of OSSB signals, the eye opening in the eye diagram is observed even after the transmission over 50km of the SFM spool. The power penalties of the generated V-band 60GHz and the W-band 100GHz MMWs at a 10−9 bit-error-rate (BER) are 1.7dB and 2.5dB, respectively.

Optical single sideband signal generation relying on a single‐drive Mach–Zehnder modulator for radio over fibre communications

Optical single sideband (OSSB) signals are conventionally generated using a dual-drive Mach–Zehnder modulator (MZM) or by using a single-drive MZM in conjunction with a fibre Bragg grating filter. In this study, the authors propose and mathematically characterise a novel radio over fibre downlink in which an OSSB signal is generated using a single-drive, rather than dual-drive, MZM without any additional filter. Additionally, their proposed scheme can achieve optical upconversion of the electronic signal. Furthermore, in addition to cost advantages, the proposed scheme's bit error ratio (BER) performance is better than the classical OSSB signal generation scheme.

Phase-coherent orthogonally polarized optical single sideband modulation with arbitrarily tunable optical carrier-to-sideband ratio.

We propose and experimentally verify a novel approach to achieve phase-coherence orthogonally polarized optical single sideband (OSSB) modulation with a tunable optically carrier-to-sideband ratio (OCSR). In our scheme, the orthogonally polarized OSSB signal is achieved using a dual-polarization quadrature phase shift keying (DP-QPSK) modulator without an optical band-pass filter (OBPF). Therefore, the proposed method is wavelength independent. The DP-QPSK modulator includes two parallel QPSK modulators locating on its two arms. The upper QPSK modulator of the DP-QPSK modulator is driven by two quadrature sinusoidal microwave signals and works at the frequency shifting condition whose bias voltages are optimized to suppress the optical. The lower QPSK modulator of that works at the maximum transmission point and the optical carrier is not modulated. The OCSR is continuously tunable by simply adjusting the bias voltages of the lower modulator. The frequency shifting optical signal from the upper QPSK modulator and the optical carrier from the lower QPSK modulator are combined together at the output of the DP-QPSK modulator. The optical carrier and sideband are polarized orthogonally. The generated OSSB signals could be used to shift and code the phase of the microwave signal and generate ultra-wideband (UWB) microwave pulse. The proposed method is analyzed and experimental demonstrated.

Signal to Noise Ratio Penalty Analysis for Radio over Free Space Optical Systems

Due to ever-increasing demand for capacity and quality in wireless communication links, lead to inspire researchers to innovate new design methodologies and concepts over wireless systems and networks with the ultimate aim of achieving a next-generation network. These researches must ensures data rates similar to those offered by optical fiber systems but at the fraction of its deployment cost. Among the emerging technologies is the new innovative radio on freespace optics system, referred to as Radio over Free Space Optics (RoFSO), which is the main interest of this paper. RoFSO systems have been recognized as a promising wireless interconnecting technology. Such system combines the radio over fiber (RoF) technology comprising heterogeneous wireless services and Fiber Space Optics (FSO) link. In this paper, an analytical time-domain model is presented to analyze the radio over free space optical (RoFSO) systems considering scintillation effect with the log-normal distribution. This analytical model uses a dual-drive MachZehnder modulator (DD-MZM) and photodetector (PD) for optical single sideband (OSSB) signals.

Power optimized OSSB modulation to support multi-band OFDM services along hybrid long-reach WDM-PONs

In this paper, optical single sideband (OSSB) transmission of multi-services based on orthogonal frequency division multiplexing (OFDM) with different signal constellations is investigated through numerical simulation, when the modulation efficiency obtained with a dual-electrode Mach–Zehnder modulator (DE-MZM) is optimized by biasing it below its quadrature point. Furthermore, in order to overcome the intermodulation distortion resulting from modulation efficiency optimization, it is demonstrated that driving each electrical signal with a different electrical power is an effective solution for the signals considered. As result of the optimization, successful delivery after 130km of a hybrid OSSB signal composed by a custom 16-quadrature amplitude modulation (QAM) OFDM gigabit Ethernet (GbE) signal, a 20MHz 64-QAM LTE signal and three independent OFDM-UWB channels of the first group of ECMA-386 is demonstrated, with negligible power penalty.

The Dual-Electroabsorption Modulated Laser, a Flexible Solution for Amplified and Dispersion Uncompensated Networks Over Standard Fiber

We propose here a monolithically integrated dual RF access electroabsorption-modulated laser called D-EML for the generation of optical single-sideband signal for both nonreturn to zero and orthogonal frequency division multiplexing formats. The benefits of optical single-sideband over double sideband in terms of resilience against chromatic dispersion effects are presented for high-bit rate intensity modulation/direct detection transmissions over standard single mode fiber in the C-band. Both simulation and experimentation exhibit transmission distance enhancement in the case of dual modulation of the D-EML, i.e., in optical single-sideband configuration, making this optical source an interesting solution because of its low-cost, low-size, and reasonable-power consumption.

Optical Single Sideband Modulation With Tunable Optical Carrier-to-Sideband Ratio

A novel approach to realize optical single sideband (OSSB) modulation with tunable optical carrier-to-sideband ratio (OCSR) is proposed and demonstrated based on cascaded polarization modulators (PolMs). In the proposed scheme, OSSB polarization modulation is first obtained by driving two cascaded PolMs with two RF signals that are 90 ° out of phase. Then, by placing a polarizer after the PolMs, an OSSB-modulated signal with a tunable OCSR is obtained by adjusting the polarization direction of the polarizer. An experiment is carried out. An OSSB signal with a tunable OCSR from -26 to 46 dB is achieved. The operation bandwidth covers the frequency range of 5-35 GHz.

Simple ku‐band radio over fiber system with high‐dispersion tolerance using a polymer‐based microring resonator filter

AbstractThis article presents an optical single sideband (SSB) signal generation in radio over fiber system using a polymeric microring resonator as an optical notch filter, alleviating the fiber chromatic dispersion‐induced carrier fading problem. With this technique, optical SSB radio frequency (RF) signal with a RF frequency of 14.35 GHz carrying 40‐Mbps quadrature phase shift keying vector signal is generated. This signal is transmitted over 25‐km standard single‐mode fiber successfully, and the received signal error vector magnitude is 5.8% rms. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1129–1133, 2014

Optical single sideband modulation using fiber nonlinearity and injection locked technology in radio‐on‐fiber systems

ABSTRACTWe propose a transmission system based on stimulated Brillouin scattering (SBS) effect and injection locked distributed‐feedback (DFB) laser to achieve optical single sideband (OSSB) modulation. These two kinds of technologies fall on frequency band approximately nearby 10.8 GHz to enhance OSSB signal. The first step drives radio frequency signal into modulator and uses SBS effect to enhance right sideband. The second step based on injection locked DFB laser achieves OSSB modulation. After 25‐km single mode fiber transmission, we can observe the sideband power ratio > 15.81 dB and performances for bit error rate analysis with power penalty about 5.2 dB at 10−8. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:274–278, 2014

Optimization of optical single sideband configurations for radio over fiber transmission and multi-type data communication over a DWDM link

Two new optical single side band (OSSB) configurations for radio frequency (RF) transmission of data are proposed based on the structures that have been designed for baseband digital data transmission. The performances of these schemes are evaluated based on the relevant eye diagrams and bit error rate (BER). The proposed configurations are studied and analyzed mathematically. Eye diagrams and BER’s indicate an acceptable performance for the suggested structures. Feasible settings for the RF electrical power of the links are considered and the link performance for each setting is evaluated. A 4-dense wavelength division multiplexing (4-DWDM) link is considered for transmitting different types of data over a single mode fiber (SMF). Baseband digital data in the format of OSSB and RF-OSSB signals are transmitted over a 4-DWDM link. Furthermore, the link performance is considered for different electrical power settings of OSSB signal in order to achieve efficient transmission for DWDM network.

A Novel Approach to Realizing SSB Modulation With Optimum Optical Carrier to Sideband Ratio

A novel approach to realizing single sideband (SSB) modulation with optical carrier to sideband ratio (OCSR) of 0 dB, which is optimum for maximizing the transmission performance of a radio-over-fiber system, is proposed and experimentally demonstrated based on a strong optical injection-locked distributed feedback (DFB) laser. Tunable OCSR with optimum value of 0 dB is achieved by tuning the injection ratio and the detuning frequency precisely. A simulation is carried out to confirm the optimum OCSR. Gain properties of the DFB laser under strong optical injection are also measured for the first time to our knowledge. Doubled frequency of the LO signal is obtained without any filter. The generated optical SSB signal of 20 GHz is transmitted over 60-km single-mode fiber experimentally; results show it is almost not affected by the fiber chromatic dispersion.

Performance optimization of radio-on-fiber systems employing erbium doped fiber amplifier for optical single sideband signals considering intermodulation distortion

The performances of radio on fiber (RoF) systems with a dual-electrode Mach-Zehnder modulator and an erbium-doped fiber amplifier (EDFA) are optimized by numerical equations including the third order intermodulation (IM3) as well as amplified spontaneous emission (ASE) noise. We investigate a signal-to-noise-and-distortion ratio (SNDR) considering fiber dispersion with respect to an input signal power and an EDFA gain in both noise-dominant and third order intermodulation (IM3)-dominant cases. We also verify that the numerical analysis results are well matched with those of a commercial simulator, VPItransmissionMaker. In the analysis results, the optimum input signal power for the maximum SNDR of a RoF system with EDFA was reduced over 8 dB compared with that without EDFA. The dramatic reduction of IM3 power at a receiver was resulted from this decrement of input signal power. Thus, the maximum SNDR of the system with EDFA was obtained over 17 dB at 40 km fiber compared with that of the system without EDFA. In addition, the results showed that the SNDR was efficiently improved by EDFA in the noise-dominant case, while the SNDR improvement was negligible by EDFA in the IM3 dominant case.

Received Power performance in downlink architecture of Radioover-Fiber Transmission system using OSSB Techniquedue to chromatic dispersion and laser linewidth

The In this paper, we studied the RoF system and analyzed the received power performance in downlink architecture of RoF system. The RoF system employs a Mach-Zehnder modulator (MZM) and a phase shifter to externally generate an optical single sideband (OSSB) signal since the OSSB signal is tolerable for power degradation due to a chromatic fiber-dispersion effect. The received power performance is analyzed by calculating a factor called Power Penalty. It is shown that Power penalty is increased exponentially as the differential delay increased with the distance due to chromatic dispersion with the change in laser linewidth

Perfectly Orthogonal Optical Single-Sideband Signal Generation Based on Stimulated Brillouin Scattering

We experimentally demonstrate a perfectly orthogonal optical single-sideband signal generation technique using stimulated Brillouin scattering. By using both the Brillouin gain and loss, a perfectly orthogonal optical single-sideband signal is achieved. In addition, the modulation depth of the single-sideband signal is adjustable by separately tuning the gain and loss for the optical carrier.

Analytical Time-Domain Model for Radio over Free Space Optical (RoFSO) Systems Considering the Scintillation Effect

An analytical time-domain model is presented to analyze a radio over free space optical (RoFSO) system considering the scintillation effect with a log-normal distribution. This analytical model uses a dual-drive Mach-Zehnder modulator (DD-MZM) and photodetector (PD) for typical optical double sideband (ODSB) and single sideband (OSSB) signals. We show the output current of PD as a function of the summation of each frequency component in time domain. Finally, we calculate the received signal power with respect to the power spectral density (PSD) and derive a closed-form average bit error rate (BER) performance.

Optical frequency tripling with improved suppression and sideband selection

A novel optical dispersion tolerant millimetre-wave radio-over-fibre system using optical frequency tripling technique with enhanced and selectable sideband suppression is demonstrated. The implementation utilises cascaded optical modulators to achieve either an optical single sideband (OSSB) or double sideband-suppressed carrier (DSB-SC) signal with high sideband suppression. Our analysis and simulation results indicate that the achievable suppression ratio of this configuration is only limited by other system factors such as optical noise and drifting of the operational conditions. The OSSB transmission system performance is assessed experimentally by the transport of 4 WiMax channels modulating a 10 GHz optical upconverted RF carrier as well as for optical frequency doubling and tripling. The 10 GHz and tripled carrier at 30 GHz are dispersion tolerant resulting both in an average relative constellation error (RCE) of -28.7 dB after 40 km of fibre.

All-optical frequency upconversion of a quasi optical single sideband signal utilizing a nonlinear semiconductor optical amplifier for radio-over-fiber applications

An all-optical frequency upconversion technique using a quasi optical single sideband (q-OSSB) signal in a nonlinear semiconductor optical amplifier (NSOA) for radio-over-fiber applications is proposed and experimentally demonstrated. An optical radio frequency signal (f(RF) = 37.5 GHz) in the form of a q-OSSB signal is generated by mixing an optical intermediate frequency (IF) signal (f(IF) = 2.5 GHz) with an optical local oscillator signal (f(LO) = 35 GHz) utilizing coherent population oscillation and cross gain modulation effects in an NSOA. The phase noise, conversion efficiency, spurious free dynamic range (SFDR), and transmission characteristics of the q-OSSB signal are investigated.

Performance Improvement of Optical Single Sideband Signal Using an Integrated Mach-Zehnder Modulator

A novel integrated Mach-Zehnder modulator consisting of three phase modulators to generate an optical single sideband with carrier signals in the radio-over-fiber system has been proposed. By adjusting the direct current voltage applied in the modulation arm, named the “direct current arm,” the power of the optical carrier in the optical single sideband signal is controllable, and the optimal carrier-to-sideband ratio of 0 dB can be achieved for any modulation index. The simulation results show that the receiver sensitivity can be greatly improved, and the radio-over-fiber system based on the proposed technique has better robustness.

Optimisation of carrier-to-sideband ratio by triple-arm Mach–Zehnder modulators in radio-over-fibre links

A novel Mach–Zehnder modulation technique based on a 1×3 multimode interference coupler and three optical phase-modulator waveguides for the generation of optical single sideband (SSB) signals in the radio-over-fibre millimeter-wave system is proposed. Two of the three modulator arms are biased by the direct current (DC) voltage and modulated by the radio frequency (RF) signal in the same way as conventional SSB modulation method to produce optical RF signals, but the third one which can be named as ‘dc arm’ is only biased by DC to change the path of the optical carrier passing through it. The interference at the output of the triple-arm modulator happens at the optical carrier frequency, which makes the power of the optical carrier in the SSB signal controllable. Optimised modulation depth between the sideband component and the carrier of the generated SSB signal could be obtained by adjusting the bias voltage applied to the ‘dc arm’. It is proposed and analysed that the novel technique could improve the sensitivity of the optical receiver significantly compared with the conventional SSB modulation scheme.