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A microwave photonic radar system with optical generation and de-chirping processing of broadband linear frequency modulated continuous-wave signal is proposed for high-resolution and real-time inverse synthetic aperture radar (ISAR) imaging. A K-band microwave photonic radar prototype is established and the ISAR imaging feasibility is experimentally investigated. The imaging results verify that the...
A photonic analog-to-digital converter with multiplied sampling rate based on a fiber ring is proposed and demonstrated. Using optical pulses with 100-MHz repetition rate, equivalent sampling rates with multiplication factors of 5 and 7 are experimentally achieved. The proposed approach features simple configuration with no parallel structure, which can find application in photonics-based coherent...
A compact optical-microwave phase detector is proposed and its performance is evaluated by synchronizing an 8-GHz oscillator to a 250-MHz mode-locked laser. The residual out-of-loop phase noise at 1 Hz and 100 kHz offset are −115 dBc/Hz and −146 dBc/Hz respectively. And the RMS timing jitter is 600 as when integrated from 100 kHz to 1 Hz. The proposed phase detector has a compact structure and is...
A novel optically tunable frequency-multiplying optoelectronic oscillator (OEO) to generate a high frequency microwave signal without employing an optical filter is proposed. The upper dual parallel Mach-Zehnder modulator (DP-MZM) integrated in a dual-polarization quadrature phase shift-keying (DP-QPSK) modulator is accurately biased to serve as an equivalent phase modulator (e-PM), which functions...
A broadband photonic RF channelizer with large in-band interference suppression is proposed and experimentally demonstrated based on dual optical frequency combs (OFCs) and photonic image-reject mixers (IRMs). A Ku-band RF signal with a bandwidth of 5 GHz is channelized into five sub-channels with 1-GHz instantaneous bandwidth. The in-band interference, which is a serious problem of conventional photonics-based...
A photonic linear frequency-modulated (LFM) microwave waveform generator is proposed and demonstrated using a tunable optoelectronic oscillator (OEO) based on an optically injected semiconductor laser. Frequency tunability of the OEO is achieved by controlling optical injection strength. When the sweep period of output frequency matches with the cavity round-trip time, signal quality of generated...
We design and investigate a frequency synthesizer for generating a serial of low-phase-noise frequencies from 5.9GHz to 12.9GHz using an optoelectronic oscillator (OEO) as the reference. The 10 GHz free-running OEO has an ultra-low phase noise of −136dBc/Hz at 10 kHz offset. The phase noise of the constructed frequency synthesizer at 10 kHz offset is from −135dBc/Hz to −125dBc/Hz. The spurious suppression...
A high-sensitivity phase noise measurement scheme using photonic-delay line and digital phase demodulation is proposed, which is free of complicate calibration and amplitude noise by using digital phase demodulation. In the experiment, a phase noise measurement sensitivity as high as −134 dBc/Hz@10 kHz@10 GHz is achieved applying a 2-km single mode fiber as the delay line. Besides, accurate phase...
A microwave photonic based RF interference cancellation scheme is proposed to compensate for wideband phase changes of the interference signals, in which microwave photonic phase shifter is particularly employed. In the proposed cancellation scheme, a known interferer is delayed, attenuated, phase shifted so as to be subtracted from the received signal at the output. The microwave photonic phase shifter...
In this paper, we propose the mirror-symmetric Fano-like resonances which are generated by the interference between two resonant beam from through and drop ports of an add-drop microring resonator. While the path lengths of the two beams are different, small quasi-periodic spectral responses are nested in large periodic ones. The line shapes of the resonances are mirror images about the center wavelength...
RF front-end based on microwave photonics is presented and demonstrated. A proof-of-concept RF front-end covering S-Ka bands is successfully realized. Image-reject frequency down-conversion and channelized receiving is realized. Reconfigurable photonic frequency up-conversion for RF signals emitting is also demonstrated.
A full-polarization optical spectrum analyzer is proposed based on a frequency-swept microwave-photonic source and balanced photodetection. A resolution of 0.75 MHz (6 fm) and a dynamic range of >57 dB were experimentally achieved.
We propose and demonstrate a coupled optoelectronic oscillator (COEO) based on enhanced spatial hole burning (SHB) effect in an unpumped erbium-doped fiber (EDF). A novel structure is designed to form strong standing waves in the unpumped EDF, which enables large SHB effect to improve the side-mode suppression and ensure stable operation. A proof-of-concept experiment is carried out. A 10-GHz stable...
A photonic microwave image-reject and singlesideband mixer is proposed based on a dual-polarization dualdrive Mach-Zehnder modulator. Results show that the image- and sideband-reject ratios of the proposed IRM and SSM are larger than 60 and 30 dB, respectively, and the LO leakage is largely suppressed.
A simple method for generating linearly chirped microwave waveforms (LCMWs) with ultra-large time-bandwidth product (TBWP) is proposed using an optically injected semiconductor laser. The generation of an LCMW with a TBWP as large as 1.2 × 105 (10 μs, 12 GHz) is demonstrated.
A serial photonic digital-to-analog converter (PDAC) is proposed and demonstrated. The established 4-bit PDAC has a good linearity and the effective number of bits reaches 3.49. Based on the PDAC, the generation of cosine, triangular, sawtooth, parabolic and square waveforms is implemented with good performance.
Microwave measurement refers to the acquisition of parameters of a microwave signal or the identification of properties of an object using microwave-based approaches. Thanks to the broad bandwidth and high speed provided by modern photonics, microwave measurement in the optical domain can provide better performance in terms of bandwidth and speed which may not be achievable using state-of-the-art...
A photonic approach for the generation of widely tunable phase-coded microwave signals based on a novel micro-ring polarization rotator (MRPR) is theoretically proposed. The MRPR is a micro-ring with asymmetric waveguides structure in the coupling region. The device has the characteristics of both polarization rotation and wavelength selection, which can make the carrier and sideband orthogonally...
This paper reviews and discusses the recent efforts on developing optical vector analysis based on swept optical single-sideband modulation, which can achieve the magnitude and phase responses of optical devices with sub-MHz resolution.
A microwave downconverter based on optical single-sideband modulation by a dualdrive Mach-Zehnder modulator and carrier suppression by a fiber Bragg grating is proposed and demonstrated, which implements multi-octave downconversion with suppressed mixing spurs.
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