Microwave frequency-hopping signal generation is one of the backbone components in modern wireless communication system. In this paper, we propose a novel photoelectric integrated approach to implement broadband microwave frequency-hopping signal generation. The coherent dual optical combs are constituted by two Mach Zehnder modulators (MZMs) and one acousto-optic frequency modulator (AOM). By using dense wavelength division multiplexing (DWDM) and single-sideband modulation with carrier suppression, the proposed method extends the input signal's frequency hopping bandwidth by six times. Due to the photoelectric hybrid structure, the proposed method can achieve precise control for using electronic technology while also providing the advantages of high bandwidth and reconfigurability through photonics. In the experiment, the frequencies of generated signals can hop ranging from 0 to 6GHz. Meanwhile, the frequency hopping signals can maintain a well signal quality with the EVM lower than 6.4%.

Image-reject radio frequency (RF) receiver is the backbone of modern RF systems, but often suffers from limited bandwidth, local oscillator (LO) leakage, even-order distortion and I/Q imbalance. A wideband photonic image-reject RF receiver based on two phase-modulators (PMs) in a Sagnac loop and an I/Q balanced detector is proposed. In the experiment, excellent I/Q amplitude balance (<0.8 dB) and phase balance (<0.7 degrees) over a wide operating frequency from 8 to 40 GHz are achieved. Due to balanced detection, the even-order distortion and dc-offset are significantly suppressed. Combined with an analog intermediate frequency (IF) quadrature coupler, the image-reject RF receiver is implemented with a spurious free dynamic range (SFDR) of 99.4 dBHz2/3 and an image rejection of 50.3 dB. An antenna remoting RF vector signal with image interference is down-converted to the IF domain. Benefiting from the significant image rejection and Sagnac loop architectonics, a good constellation diagram and a low error vector magnitude (EVM) of the desired signal are obtained.

In order to meet the requirements of large instantaneous bandwidth, wide operating frequency range, large dynamic range, and anti-interference for microwave parameter measurement in the new generation radar system and real-time signal processing system, a microwave photonic Doppler frequency shift (DFS) and angle of arrival (AOA) measurement scheme based on Mach–Zehnder modulator (MZM) and acousto-optic modulator (AOM) is proposed in this article. The designed structure can clearly identify the direction of the DFS and avoid the intermodulation distortion and low-frequency interference. In addition, the upper and lower optical sidebands are fully utilized to effectively avoid the frequency error caused by the AOM driver module and improve the measurement accuracy of the system. In the experiment, the error of the microwave DFS at an ultrawide operation frequency from 6 to 36 GHz is between ±0.15 Hz with a clear direction. The micro-DFS (mDFS) measurement is also carried out to demonstrate the advantage of low-frequency DFS measurement. It is also verified that the phase difference error is less than 1° in the AOA measurement experiment. The proposed scheme has advantages such as multifunction and anti-interference, thus having great application prospects.

A scheme for realizing a zero-intermediate frequency (IF) channelized receiver using a dual-polarization quadrature phase-shift keying (DP-QPSK) modulator and a narrow-band optical filter is proposed. The channelized system only requires one optical frequency comb to achieve zero-IF multi-channel reception of wideband signals, and the spacing of the optical frequency comb only needs to be equal to the sub-channel width, which is very easy to implement. It is found that using photonic IQ demodulation and balanced detection and reception technology can not only eliminate many disadvantages of the traditional zero-IF receiver, including local oscillator (LO) leakage, direct current (DC) offset, even-order distortion, and in-phase/quadrature (I/Q) imbalance, but also reduce the bandwidth and sample rate of the analog-to-digital converter (ADC). It is theoretically proven that the radio frequency (RF) signal with a bandwidth of 3 GHz can be divided into five sub-channels with a bandwidth of 600 MHz and finally demodulated to I/Q basebands, which are also verified with simulation.