Photonic Vector Signal Research Articles

Generation of (3, 1) Vector Signal Based on Probabilistic Shaping Technology without Precoding

In this paper, we introduce the probabilistic shaping (PS) technique to the normal (3, 1) vector signal and simulate the generated PS (3, 1) photonic vector signal on an optical transmission system. The PS (3, 1) photonic vector signal is generated by a radio frequency (RF) signal at 12 GHz driving a Mach–Zehnder modulator- (MZM-) based optical carrier suppression (OCS) doubling, and the PS (3, 1) photonic vector signal is not precoding. The PS (3, 1) photonic vector signal and the normal (3, 1) photonic vector signal are used to transmit in 5 km, 10 km, and 20 km single-mode fibers (SMF), respectively. The simulation results demonstrate that the bit error ratio (BER) of the PS (3, 1) vector signal is less than the forward error correction (FEC) threshold of 3.8 × 10−3, and the BER performance is better than that of the normal (3, 1) vector signal at 4 Gbit/s and 8 Gbit/s transmission rates.

Adaptive Reed–Solomon coding and envelope detection of photonic vector signal in V-band radio over fiber system

In this paper, a millimeter-wave radio-over-fiber (RoF) system based on adaptive Reed–Solomon (RS) coding scheme and envelope-detector-based (ED-based) down-conversion for 16-quadrature amplitude modulation (16-QAM) vector signal are proposed and experimentally investigated, which makes the ROF systems simpler, lower-cost and more robust to the phase noise of the generated millimeter-wave signals compared with the conventional system. The transmission of RS-coded 16-QAM vector signals with the bit rate of 2-Gb/s and 4-Gb/s at 60-GHz over 20-km standard single mode fiber (SSMF) and 2-m wireless distance are successfully achieved. RS coding module is adaptively performed via the last received codeword error rate (CER) estimated by the output of the first RS encoder. The experimental results show that the post-FEC bit error rate (BER) of 1×10−8 can be obtained by adaptive RS coding scheme with the flexible and optimum code rate and redundancies.

Photonic Vector Signal Generation Based on OEO and Optical Coherent QPSK Modulation

A novel scheme for photonic vector signal generation based on a self-starting optoelectronic oscillator (OEO) and optical coherent quadrature phase-shift keying (QPSK) modulation is proposed and experimentally demonstrated. The optical output sidebands of the OEO are employed for optical heterodyne mixing, where one first-order sideband is modulated by QPSK baseband data using a dual-parallel Mach–Zehnder modulator, followed by coherent detection so as to directly generate frequency-doubled K-band vector signals. In the experiment, a 19.9 GHz QPSK modulated vector signal with a bit rate of 100 Mb/s is generated when the OEO operates at 9.95 GHz. The generated signal is back demodulated with error vector magnitude (EVM) less than 7%.

Photonic RF vector signal generation with enhanced spectral efficiency using precoded double single-sideband modulation.

In this study, a novel photonic vector signal at frequency (RF) bands generation scheme based on the beating of double single sidebands (SSBs) is proposed and experimentally demonstrated. The double SSBs carry separate constant- or multi-amplitude quadrature-amplitude-modulation vector signals are generated from a single I/Q modulator. By adopting phase and amplitude precoding, different constellations can be generated, such as 3-ary phase-shift keying (PSK), 4-PSK, 7-PSK, 8-PSK, and so on. In this work, 10-Gbaud 7-PSK vector signal generation at 20 GHz enabled by two precoded 4-PSK SSB signals via a single I/Q modulator is theoretically and experimentally investigated. Compared to a single-drive Mach-Zehnder modulator or conventional I/Q modulator-based photonic vector signal generation scheme, the spectrum efficiency can be doubled. Differential coding is also implemented at the transmitter side for accurate demodulation of 7-PSK into two 4-PSK signals. The bit-error ratio for 10-Gbaud 7-PSK vector signals can be under hard-decision forward-error-correction threshold of 3.8×10-3 after 10 km standard single-mode fiber transmission.

Photonic frequency-quadrupling and balanced pre-coding technologies for W-band QPSK vector mm-wave signal generation based on a single DML

We propose a novel scheme for high-frequency quadrature phase shift keying (QPSK) photonic vector signal generation based on a single directly modulated laser (DML) employing photonic frequency quadrupling and balanced pre-coding technologies. In order to realize frequency quadrupling, a wavelength selective switch (WSS) is intruded in our experiment. The intruded WSS combined with DML can not only realize high-frequency vector signal generation but also simplify the architecture. We experimentally demonstrate 1-or 2-Gbaud QPSK vector signal generation at 88GHz based on our proposed scheme. The generated 1-Gbaud balanced pre-coded QPSK vector signal is transmitted 0.5-m wireless distance with the bit-error-ratio (BER) below hard-decision forward-error-correction (HD-FEC) threshold of 3.8×10−3. To our knowledge, this is the first time to demonstrate W-band mm-wave vector signal based on a single DML with quadrupling frequency and pre-coding technologies.

Photonic Vector Signal Generation Employing a Single-Drive MZM-Based Optical Carrier Suppression Without Precoding

We propose and investigate a novel and simple photonic vector signal generation scheme at radio frequency bands enabled by a single-drive Mach–Zehnder modulator-based optical carrier suppression without precoding techniques and optical filter, which can reduce the complexity of transmitter digital signal processing. The generation and reception of 16/20/22-Gbaud quadrature-phase-shift-keying vector signals at 16/20/22 GHz are experimentally demonstrated, respectively. The measured bit-error ratio for 16 G-baud QPSK vector signals after transmitting over 10-km standard single mode fiber can be under 7% hard-decision forward-error-correction threshold of 3.8 × 10−3. Moreover, compared to the conventional precoding scheme, the receiver sensitivity can be enhanced by 4 dB at both back-to-back and after 10-km SSMF transmission cases, which demonstrates the feasibility of this proposal, and show its potential promising application in radio over fiber system.

W-band OFDM photonic vector signal generation employing a single Mach-Zehnder modulator and precoding.

We present a simple radio-over-fiber (RoF) link architecture for millimeter-wave orthogonal frequency division multiplexing (OFDM) transmission using only one Mach-Zehnder modulator (MZM) and precoding technique. In the transmission system, the amplitudes and the phase of the driving radio-frequency (RF) OFDM signal on each sub-carrier are precoded, to ensure that the OFDM signal after photodetector (PD) can be restored to original OFDM signal. The experimental results show that the bit-error ratios (BERs) of the transmission system are less than the forward-error-correction (FEC) threshold of 3.8 × 10(-3), which demonstrates that the generation of OFDM vector signal based on our proposed scheme can be employed in our system architecture.

Photonic vector signal generation at W-band employing an optical frequency octupling scheme enabled by a single MZM

We propose photonic vector signal generation at millimeter-wave (mm-wave) bands enabled by a single Mach–Zehnder modulator (MZM) and phase-precoding technique, which can realize photonic frequency multiplication of the precoded microwave vector signal used for the drive of the single MZM. We also experimentally demonstrate the generation of quadrature-phase-shift-keying (QPSK) modulated vector signal at W-band adopting photonic frequency octupling (×8) based on our proposed scheme. The MZM is driven by a 12-GHz QPSK modulated precoded vector signal. Up to 4-Gbaud QPSK-modulated electrical vector signal at 96GHz is generated and then delivered over 3-m wireless transmission distance.

High-frequency photonic vector signal generation employing a single phase modulator

In this paper, we propose a novel and simple method to generate millimeter-wave vector signals using only one phase modulator (PM) and phase-precoding technique, in which the precoded microwave vector signal is used for the drive of the single PM. We experimentally demonstrate that this concept of the generation of quadrature-phase-shift-keying-modulated vector signal can be employed in our radio-over-fiber (RoF) system architecture based on our proposed scheme. By this scheme, we simplify the configuration and reduce the cost of the RoF system.

Photonic vector signal generation employing a novel optical direct-detection in-phase/quadrature-phase upconversion

This work demonstrates the feasibility of the generation of an RF direct-detection vector signal using optical in-phase/quadrature-phase (I/Q) upconversion. The advantage of the proposed transmitter is that no electrical mixer is needed to generate the RF signal. Therefore, I/Q data of RF signals are processed at baseband at the transmitter, which is independent of the carrier frequency of the generated RF signal. A 10 Gb/s 16 quadrature amplitude modulation signal is experimentally demonstrated. Following transmission over a 50 km single-mode fiber, the power penalty is negligible. Moreover, I/Q imbalance of the proposed transmitter is studied and compensated by digital signal processing, which is both numerically and experimentally verified.

Photonic vector signal generation at microwave/millimeter-wave bands employing an optical frequency quadrupling scheme

To the best of our knowledge, a novel photonic architecture to generate vector signals at microwave/millimeter-wave bands employing an optical frequency quadrupling technique based on an external dual-parallel modulator is proposed for the first time. A 312.5 MSym/s quadruple phase-shift keying signal at 25 GHz is experimentally demonstrated using properly precoding driving signal at 6.25 GHz, and optical power penalty is negligible following 50 km single-mode fiber transmission.