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We propose and experimentally demonstrate an ultraefficient broadband photonic channelizer. By polarization-division multiplexing the received signal and using dual-output Hartley image-reject receiving topology, $4N$ channels can be generated with only ($N +1$)-line signal optical frequency comb (OFC) and $N$ -line local oscillator (LO) OFC, and the frequency interval of the OFC is reduced to half of the typical value. With the use of the integrated dual-polarization coherent detection receiver (DP-CDR), the required quadrature optical hybrid (QOH) and the balanced photodetectors (BPDs) are reduced to half. The system size is reduced and stability is improved. Besides, assisted with a digital signal processor (DSP) algorithm, the IQ imbalance can be compensated, and approximately, ideal image rejection can be realized. A proof-of-concept experiment is carried out. A 2–14-GHz wideband signal is successfully divided into 12 channels with 1-GHz bandwidth by applying four-line signal OFC and three-line LO OFC. The image rejection ratio (IRR), channel isolation (CI), and spurious-free dynamic range (SFDR) are also measured and discussed. [ABSTRACT FROM AUTHOR]

Nonlinear distortion and chromatic dispersion are two long-standing limiting factors of radio-over-fiber (ROF) links. Here, we proposed an ROF link with both the two problems mitigated simultaneously. Furthermore, a tunable optical carrier-to-sideband ratio (CSR) can also be implemented in this simple system to improve the gain and the noise figure (NF) of the link. All these three factors are optimized in a simple ROF link which shows increased performance of the system. The scheme is based on a single dual-polarization Mach–Zehnder modulator (DPol-MZM). One bias voltage of the Dpol-MZM is employed to mitigate the nonlinear distortion. The polarization direction and the phase relationship of the modulated polarization multiplexed signal are used to adjust the CSR and suppress the dispersion, respectively, by adjusting a polarization controller (PC). In the experiment, 3–30-GHz RF signal is transmitted without power fading. A two-tone signal with the frequencies of 12.5 and 12.505 GHz is employed to verify the optimization of three main parameters of the ROF link [link gain, NF, and spurious-free dynamic range (SFDR)] where the link gain, NF, and SFDR are improved by 11.9, 5.8, and 14.5 dB, respectively, compared with conventional quadrature biased link based on one Mach–Zehnder modulator for 50-km single-mode fiber (SMF) transmission. Meanwhile, 100-Mbaud 16 quadrature amplitude modulation (QAM) signals centered at 12.5 and 14.7 GHz are used to verify the transmission performance. After dispersion compensation, nonlinear optimization, and CSR optimization, error vector magnitude (EVM) is improved from 17.03% to 2.97%. [ABSTRACT FROM AUTHOR]

A novel photonic microwave and millimeter-wave (mm-wave) mixer with simultaneous third-order intermodulation distortion (IMD3) suppression and dispersion-induced power fading compensation is proposed and experimentally demonstrated. In our proposed scheme, a dual-polarization quadrature phase shift-keying (DP-QPSK) modulator is used to modulate RF/IF and LO signals. The bias voltages of the main modulators are adjusted to compensate dispersion-induced power fading. When the polarization state of the modulated signal and the attenuation of the RF signal are properly adjusted, IMD3 distortion can be suppressed. In the experiment, relatively flat microwave and mm-wave signals from 11 to 35 GHz are obtained through 4- and 50-km fiber transmission, while the measured spurious free dynamic range (SFDR) is $112.9~{\mathrm {dB}} \cdot \text{Hz} ^{4/5}$. In addition, an up-converted 16 quadrature amplitude modulation (16 QAM) vector signal with a carrier frequency of 19.3 GHz is obtained and the measured constellation diagrams and error vector magnitudes are given after transmission over different fiber lengths (back to back, 4 and 50 km). [ABSTRACT FROM AUTHOR]

Microwave I/Q up-converter is widely used in modern electronic systems to achieve single-sideband (SSB) up-conversion and vector modulation. However, due to the frequency-dependent mixer and quadrature coupler, conventional electronic I/Q up-converters suffer limited operating bandwidth. In this paper, a photonic microwave I/Q up-converter is proposed using a polarization-division multiplexing modulator. The I/Q up-conversion channels are built in all-optical methods without any frequency-dependent devices, so a wide operating bandwidth is obtained. Balanced detection is also realized to reduce the noise figure. In the experiment, SSB signals with wide operating bandwidth (14–40 GHz), high sideband and carrier suppression (>20 dB), and large spurious-free dynamic range (110.4 Hz2/3) are generated. 16 and 64 quadrature amplitude modulation vector signals with data rates of 400 and 600 Mb/s at 40-GHz carrier frequency are also demonstrated. Furthermore, subharmonic I/Q up-conversion with similar performance is also realized using the same structure, which can well reduce the frequency requirement of the local oscillator signal and the drive circuits. [ABSTRACT FROM AUTHOR]

Zero-intermediate frequency (IF) receiver features the advantages of compact structure and agile operating frequency, but faces the problems of local oscillator (LO) leakage, direct current (dc) offset, even-order distortion, and in-phase/quadrature (I/Q) imbalance. In this paper, a photonic microwave I/Q mixer for zero-IF receiver is proposed based on a single integrated polarization multiplexing Mach–Zehnder modulator (PDM-MZM). Thanks to its all-optical operation and LO power optimization, an I/Q phase imbalance below 0.9°, an isolation ratio below −30 dB, and a typical conversion gain of −2.3 dB are achieved over an ultra-wide operating frequency from 10 to 40 GHz. Combined with the balanced detection techniques, the dc offset and even-order distortions are well suppressed, and the typical third-order spurious free dynamic range is 107.9 dB $\cdot $ Hz ^{2/3} . Using the proposed photonic I/Q mixer, the vector signals with various modulation formats, carrier frequencies, and data rates (200–700 Mb/s) are directly demodulated to I/Q basebands, and the error vector magnitude and the bit rate error are measured with the power range from −25 to 15 dBm. Subharmonic vector I/Q demodulation is also experimentally demonstrated. The proposed all-optical, ultra-wideband and high-efficient microwave I/Q mixer is suitable for a zero-IF receiver and may find potential applications in electronic systems such as wideband wireless communications, frequency-hopping radar, or multiband satellite transponder. [ABSTRACT FROM PUBLISHER]

A frequency-multiplying optoelectronic oscillator (OEO) with a tunable multiplication factor to generate a frequency-quadrupled, sextupled, or octupled microwave signal without using an optical filter is proposed and experimentally demonstrated, for the first time to the best of our knowledge. In the proposed OEO, a polarization modulator (PolM), a polarization controller (PC), and an optical polarizer (Pol) function jointly as a Mach–Zehnder modulator (MZM). Microwave oscillation is achieved in the OEO by feedbacking the intensity-modulated signal to the PolM after photodetection, and the oscillation frequency is determined by the center frequency of an electrical bandpass filter (EBPF) in the loop. A frequency-multiplied microwave signal is generated by a joint use of the PolM and a second modulator to generate two sidebands at the \pm second, \pm third, or \pm fourth orders with the sidebands at other orders fully suppressed. By beating the two sidebands at a second photodetector (PD), a frequency-quadrupled, sextupled, or octupled microwave signal is generated. An experiment is performed. A fundamental microwave signal at 9.957 GHz is generated in the OEO loop, which is multiplied to generate a frequency-quadrupled, sextupled, or octupled microwave signal at 39.828, 59.742, or 79.656 GHz, respectively. The phase-noise performance of the frequency-multiplying microwave signal is also investigated. [ABSTRACT FROM PUBLISHER]