Millimeter-wave Signal Generation Research Articles

基于光载波抑制调制的可调谐高倍频毫米波信号发生器

基于光载波抑制调制的可调谐高倍频毫米波信号发生器

Optical single sideband millimeter-wave signal generation and transmission using 120° hybrid coupler

We propose a novel 60 GHz optical single sideband (OSSB) millimeter-wave (mm-wave) signal generation scheme using 120° hybrid coupler based on external integrated Mach–Zehnder modulator (MZM). The proposed scheme shows that the bit error ratio (BER) performance is improved by suppressing the +2nd-order sideband. Meanwhile, the transmission distance is extended as only the optical +1st-order sideband is modulated by using 5 Gbit/s baseband signal while the carrier is blank, owing to the elimination of walk-off effect suffered from fiber dispersion. The simulation results demonstrated that the eye diagrams of the generated 60 GHz OSSB signal keep open and clear after 100 km standard single-mode fiber (SSMF). In addition, the proposed scheme can achieve 2 dB receiver sensitivity improvements than the conventional 90° hybrid coupler when transmitted over 100 km SSMF at a BER of 10−9.

Pre-coding assisted generation of a frequency quadrupled optical vector D-band millimeter wave with one Mach-Zehnder modulator.

We propose QPSK millimeter-wave (mm-wave) vector signal generation for D-band based on balanced precoding-assisted photonic frequency quadrupling technology employing a single intensity modulator without an optical filter. The intensity MZM is driven by a balanced pre-coding 37-GHz QPSK RF signal. The modulated optical subcarriers are directly sent into the single ended photodiode to generate 148-GHz QPSK vector signal. We experimentally demonstrate 1-Gbaud 148-GHz QPSK mm-wave vector signal generation, and investigate the bit-error-rate (BER) performance of the vector signals at 148-GHz. The experimental results show that the BER value can be achieved as low as 1.448 × 10-3 when the optical power into photodiode is 8.8dBm. To the best of our knowledge, it is the first time to realize the frequency-quadrupling vector mm-wave signal generation at D-band based on only one MZM without an optical filter.

Silicon microring modulator-based RF mixer for millimeter-wave phase-coded signal generation.

Phase-coded radio frequency (RF) pulses are widely adopted for radar systems as an effective signal format to enable high-range resolution. However, generating such signals conventionally requires high-speed electronics and complex RF circuitry that impose burdens on the system cost and power consumption. In particular, modern radar systems desire features such as high frequencies, e.g., in the millimeter-wave region, high compactness, and high system flexibility, which pose great challenges for the conventional all-electronics solutions. In contrast, integrated microwave photonics opens a way to solutions that are able to provide those features simultaneously, together with potential for full integration and low cost fabrication. Here, we present an integrated microwave photonic method of a binary-phase-coded millimeter-wave signal generation. The core device is a silicon microring modulator with a device size of 0.13 mm×0.32 mm and a modulation bandwidth of 23 GHz. Using RF seed frequencies of 17.5 GHz and 20 GHz, respectively, we experimentally demonstrated the generation of binary-phase-coded signals at 35 GHz and 40 GHz using our proposed approach, the performance of which was verified by a pulse compression ratio of 94 and 106, respectively. The result of this work points to the realization of a chip-scale flexible millimeter-wave signal generator.

Simultaneous Generation of Microwave, Millimeter-Wave, and Terahertz Photonic Signal Based on Two-Color Semiconductor Laser Subject to Single-Beam Optical Injection

In this paper, dual-mode semiconductor laser is presented and demonstrated experimentally based on multimode Fabry–Perot laser diode with a built-in cavity. The spacing of both emission modes can be tuned by adjusting the bias current and operating temperature of active region. The generated dual-mode resonance can give rise to terahertz (THz) photonic signal with more than 300 GHz frequency. Under an external injection mode launched into the two-color semiconductor laser condition, it is possible to simultaneously generate photonic signals with various frequencies, ranging from less than 10 GHz to several THz, by selecting a proper resonance mode as the reference mode of injection beam. In this study, photonic signal including microwave (MW), millimeter-wave (mm-wave), and THz wave whose frequency range is from a few gigahertz to more than 0.5 THz are given, and the corresponding optical spectrum and electrical spectrum for low-frequency MW signal as well as simulated electrical spectrum for high-frequency mm-wave and THz wave signal are presented and discussed in detail.

W-Band Vector Millimeter-Wave Signal Generation Based on Phase Modulator With Photonic Frequency Quadrupling and Precoding

We experimentally demonstrate W-band vector millimeter-wave (mm-wave) signal generation and its air space transmission, from constant-modulus quadrature phase shift keying modulation to multimodulus 8-ary quadrature amplitude modulation/16-ary quadrature amplitude modulation (8QAM/16QAM) modulation, employing a photonic frequency-quadrupling scheme enabled by a single phase modulator and precoding technique. As far as we know, it is the first time to realize W-band 8QAM/16QAM vector mm-wave signal generation based on a single phase modulator with photonic frequency multiplication. We also investigate by numerical simulation and experiment the effect of the radio-frequency (RF) driving peak-to-peak voltage of the phase modulator on the performance of the generated vector mm-wave signal, and find that there exists an optimal RF driving peak-to-peak voltage for the best performance of the generated vector mm-wave signal, which agrees well with our theoretical analysis.

Full-duplex radio-over-fiber system with tunable millimeter-wave signal generation and wavelength reuse for upstream signal.

A full-duplex radio-over-fiber system is proposed, which provides both the generation of a millimeter-wave (mm-wave) signal with tunable frequency multiplication factors (FMFs) and wavelength reuse for uplink data. A dual-driving Mach-Zehnder modulator and a phase modulator are cascaded to form an optical frequency comb. An acousto-optic tunable filter based on a uniform fiber Bragg grating (FBG-AOTF) is employed to select three target optical sidebands. Two symmetrical sidebands are chosen to generate mm waves with tunable FMFs up to 16, which can be adjusted by changing the frequency of the applied acoustic wave. The optical carrier is reused at the base station for uplink connection. FBG-AOTFs driven by two acoustic wave signals are experimentally fabricated and further applied in the proposed scheme. Results of the research indicate that the 2-Gbit/s data can be successfully transmitted over a 25-km single-mode fiber for bidirectional full-duplex channels with power penalty of less than 2.6 dB. The feasibility of the proposed scheme is verified by detailed simulations and partial experiments.

Optimization of Precoding Phase Distribution for Frequency-Multiplication Vector Signal Generation

Generation of optical vector millimeter-wave (mm-wave) signal based on Mach–Zehnder intensity modulator with frequency multiplication can reduce bandwidth requirement of optical and electrical components. A phase precoding scheme with constellation optimization is experimentally demonstrated in one 144-GHz mm-wave signal generation system with frequency sextupling. The bit-error-ratio (BER) performance at one BER of 3.8 × 10–3, hard-decision forward-error-correction threshold, is improved by over 3 dB using this novel scheme for 4-Gbaud quadrature-phase-shift-keying signal at D-band (110–170 GHz).

Probabilistic shaping for ROF system with heterodyne coherent detection

We investigate and compare the performance of normal and probabilistic shaping (PS) 16-ary quadrature amplitude modulation (16QAM) in a photonic vector millimeter-wave (mm-wave) signal generation system adopting heterodyne coherent detection. And we obtain a better bit-error ratio (BER) performance in the PS 16QAM scheme compared to the normal 16QAM scheme in the simulation. We also for the first time experimentally demonstrate the feasibility of PS-polarization-division-multiplexing 16QAM in a photonic vector mm-wave signal generation system employing heterodyne coherent detection. We obtain the same BER in PS and normal schemes with the PS scheme providing a higher bit rate. Then we experimentally carry out the performance investigation of PS in a 16QAM-modulated radio over fiber system with 40 m wireless transmission.

Simultaneous generation of 40, 80 and 120 GHz optical millimeter-wave from one Mach-Zehnder modulator and demonstration of millimeter-wave transmission and down-conversion

We demonstrate multi-frequency QPSK millimeter-wave (mm-wave) vector signal generation enabled by MZM-based optical carrier suppression (OCS) modulation and in-phase/quadrature (I/Q) modulation. We numerically simulate the generation of 40-, 80- and 120-GHz vector signal. Here, the three different signals carry the same QPSK modulation information. We also experimentally realize 11Gbaud/s QPSK vector signal transmission over 20km fiber, and the generation of the vector signals at 40-GHz, 80-GHz and 120-GHz. The experimental results show that the bit-error-rate (BER) for all the three different signals can reach the forward-error-correction (FEC) threshold of 3.8×10−3. The advantage of the proposed system is that provide high-speed, high-bandwidth and high-capacity seamless access of TDM and wireless network. These features indicate the important application prospect in wireless access networks for WiMax, Wi-Fi and 5G/LTE.

Four-amplitude shift keying-single sideband millimeter-wave signal generation with frequency sextupling based on optical phase modulation

We have proposed and demonstrated a scheme to generate a frequency-sextupling amplitude shift keying (ASK)-single sideband optical millimeter (mm)-wave signal with high dispersion tolerance based on an optical phase modulator (PM) by ably using the−4th-order and +2nd-order sidebands of the optical modulation. The ASK radio frequency signal, superposed by a local oscillator with the same frequency, modulates the lightwave via an optical PM with proper voltage amplitudes, the +2nd-order sideband carries the ASK signal with a constant slope while the −4th-order sideband maintains constant amplitude. These two sidebands can be abstracted by a wavelength selective switch to form a dual-tone optical mm-wave with only one tone carrying the ASK signal. As only one tone bears the ASK signal while the other tone is unmodulated, the generated dual-tone optical mm-wave signal has high dispersion tolerance.

Millimeter-Wave Signal Generation With Tunable Frequency Multiplication Factor by Employing UFBG-Based Acousto-Optic Tunable Filter

In this paper, a simple and cost-effective millimeter-wave (mm-wave) signal generator with tunable frequency multiplication factor (FMF) by employing the uniform fiber Bragg grating based acousto-optic tunable filter (UFBG-AOTF) is proposed and demonstrated. A dual-driving Mach–Zehnder modulator (MZM) is used to generate multisidebands. The UFBG-AOTF can select the target sidebands. A tunable FMF of even times can be achieved by adjusting the frequency of the applied acoustic wave on the UFBG. Two homemade UFBG-AOTFs are used in a basic radio-over-fiber (RoF) system, resulting in the generation of mm-waves with the FMF of 2 and 4, separately. Moreover, higher FMFs of 6, 8, and 10 are also obtained by simulation. It turns out that after the data transmitting through the SMF of 25 km, the corresponding power penalties are less than ${\rm{3.8 dB}}$ by employing the two homemade FBG-AOTFs. Numerical analysis, simulations, and some experiments are carried out to investigate the mechanism.

Generation of Multiple-Frequency Optical Millimeter-Wave Signal With Optical Carrier Suppression and No Optical Filter

We propose and experimentally demonstrate the generation of a multiple-frequency optical millimeter-wave (mm-wave) signal an without optical filter at the transmitter side. Forty, 80, and 120-GHz multiple-frequency optical mm-wave signals are generated simultaneously in our experiment. After 20 km standard single-mode fiber transmission, high-quality eye diagrams with large opening and high stability are obtained at these frequency bands.

Photonic generation of background-free millimeter-wave ultra-wideband signals (Invited Paper)

We review the recent progress of photonic generation of millimeter wave (MMW)-ultra-wideband (UWB) signals. To fully satisfy the standard defined by the Federal Communications Commission (FCC), the baseband signal (background signal) and the residual local oscillator (LO) signal should be well controlled. We discuss several schemes in this work for generating background-free MMW-UWB signals that are fully compliant with the FCC requirement.

Millimeter-wave signal generation for a wireless transmission system based on on-chip photonic integrated circuit structures

We demonstrate and compare two different photonic-based signal sources for generating the carrier wave in a wireless communication link operating in the millimeter-wave range. The first signal source uses the optical heterodyne technique to generate a 113 GHz carrier wave frequency, while the second employs a different technique based on a pulsed mode-locked source with 100 GHz repetition rate frequency. The two optical sources were fabricated in a multi-project wafer run from an active/passive generic integration platform process using standardized building blocks, including multimode interference reflectors which allow us to define the structures on chip, without the need for cleaved facet mirrors. We highlight the superior performance of the mode-locked sources over an optical heterodyne technique. Error-free transmission was achieved in this experiment.

Single-sideband W-band photonic vector millimeter-wave signal generation by one single I/Q modulator.

We propose a new scheme to generate single-sideband (SSB) photonic vector millimeter-wave (mm-wave) signal adopting asymmetrical SSB modulation enabled by a single in-phase/quadrature (I/Q) modulator. The driving signal for the I/Q modulator is generated by software-based digital signal processing (DSP) instead of a complicated transmitter electrical circuit, which significantly simplifies the system architecture and increases system stability. One vector-modulated optical sideband and one unmodulated optical sideband, with different sideband frequencies, located at two sides of a significantly suppressed central optical carrier, are generated by the I/Q modulator and used for heterodyne beating to generate the electrical vector mm-wave signal. The two optical sidebands are robust to fiber dispersion and can be transmitted over relatively long-haul fiber. We experimentally demonstrate the generation and transmission of 4-Gbaud 80-GHz quadrature-phase-shift-keying-modulated (QPSK-modulated) SSB vector mm-wave signal over 240-km single-mode fiber-28 without optical dispersion compensation.

W-Band Vector Signal Generation by Photonic Frequency Quadrupling and Balanced Pre-Coding

In this letter, we experimentally demonstrate the generation of W-band millimeter-wave (mm-wave) vector signal based on frequency quadrupling and balanced pre-coding technology by a single-driven Mach—Zehnder modulator (MZM). The MZM is biased at its maximum transmission point, and it is driven by a 22-GHz QPSK vector signal with balanced pre-coding. In addition, 1-/2-GBd QPSK vector signal at 88 GHz is generated after wavelength-selective-switch selection and single-ended photodiode detection. The experimental results show that, after 0.5-m wireless transmission, a bit-error-rate (BER) below than 1e-3 can be achieved. To the best of our knowledge, it is the first time to report the generation of the W-band mm-wave vector signal by using frequency quadrupling and balanced pre-coding technology.

Dual-Tone QPSK Optical Millimeter-Wave Signal Generation by Frequency Nonupling the RF Signal Without Phase Precoding

A novel dual-tone quadrature phase-shift keying (QPSK) optical millimeter (mm)-wave signal generation by frequency nonupling the radio-frequency QPSK signal via an optical phase modulator (PM) without phase precoding is proposed. To enable the generated optical mm-wave signal to resist the fiber chromatic dispersion degradation, the unmodulated −fourth-order and the QPSK-modulated +fifth-order sidebands are abstracted from the generated sidebands, considering the phase periodicity of a QPSK signal. The opto-electrical conversion efficiency is maximized by optimizing the modulation index of PM. An optical mm-wave generator along with a radio-over-fiber link is built, and the eye diagrams, constellations, and BER curves demonstrate that the frequency nonupling dual-tone QPSK optical mm-wave signal performs well. The simulated results agree well with the theoretical prediction.

Frequency-Quadrupling Vector mm-Wave Signal Generation by Only One Single-Drive MZM

We propose a novel and a simple scheme for photonic frequency-quadrupling vector millimeter-wave (mm-wave) signal generation based on only one single-drive Mach–Zehnder modulator (MZM) without optical filter. According to both our theoretical analysis and experimental demonstration, when the single-drive MZM, driven by a precoded vector radio-frequency (RF) signal, operates at its maximum transmission point and has an appropriate driving voltage, its output is mainly two second-order optical subcarriers, and can be heterodyne beat in a single-ended photodiode to realize frequency-quadrupling vector mm-wave signal generation. Unbalanced or balanced phase precoding for the driving vector RF signal can offset phase quadrupling incurred by the frequency quadrupling to ensure that the generated frequency-quadrupling vector mm-wave signal displays a regular vector modulation. Based on our proposed scheme, we experimentally demonstrate the generation of 1-GBd 40-GHz quadrature-phase-shift-keying vector mm-wave signal with the bit-error ratio less than the hard-decision forward-error-correction threshold of $3.8 \times 10^{\mathrm {{-3}}}$ . To the best of our knowledge, it is the first time to realize the frequency-quadrupling vector mm-wave signal generation based on only one single-drive MZM without optical filter.

W-Band Millimeter-Wave Vector Signal Generation Based on Precoding-Assisted Random Photonic Frequency Tripling Scheme Enabled by Phase Modulator

We propose W-band photonic millimeter-wave (mm-wave) vector signal generation employing a precoding-assisted random frequency tripling scheme enabled by a single phase modulator cascaded with a wavelength selective switch (WSS). The selected two optical subcarriers from the phase modulator output by the WSS can have several different kinds of combinations with asymmetrical orders, such as (-3, 0), (-2, 1), (-1, 2), and (0, 3). Employing our proposed precoding-assisted random frequency tripling scheme, we experimentally demonstrate 1/2-Gbd 81-GHz quadrature-phase-shift-keying (QPSK) mm-wave vector signal generation and its wireless delivery over 0.5-m air space distance. We also experimentally demonstrate that the generated mm-wave vector signal based on the minus second-order (-2nd) and first-order (1st) subcarriers, which is equivalent to that based on the minus first-order (-1st) and second-order (2nd) subcarriers, has a better bit-error-ratio (BER) performance than that based on the minus third-order (-3rd) and central (0th) subcarriers, which is equivalent to that based on the 0th and third-order (-3rd) subcarriers, when the phase modulator has a relatively small driving radio-frequency (RF) voltage, whereas an opposite result occurs when the phase modulator has a relatively large driving RF voltage, which is consistent with both our theoretical analysis and numerical simulation.