Shifeng Liu

Satellite Payloads Pay Off

Software-Defined Satellite Payloads Based on Microwave Photonics! Satellite communication offers a number of distinct features that are not readily available with other means of communication, such as seamless coverage of remote and sparsely populated areas, reliable data relay for deep-space exploration, inherent multicasting and broadcasting capabilities, and reliable performance in extreme conditions (e.g., war, earthquakes, and other adverse events) [1], [2]. In recent years, the steep rise in mobile multimedia applications and increased space exploration activity have created unprecedented opportunities for innovative satellite communication. According to a report provided by the Satellite Industry Association in September 2014, the global revenue of the satellite communication industry for 2013 reached US

Photonic generation of widely tunable phase-coded microwave signals based on a dual-parallel polarization modulator

189.2 billion-60% of global space revenue and 4% of global telecommunications revenue [3]. Apple, Google, Amazon, Facebook, and many other large technology companies are currently seeking to bolster their satellite communication systems in the next five to ten years, fostering a continuous increase of revenue in this area.

Multichannel Up-Conversion Based on Polarization-Modulated Optoelectronic Oscillator

A photonic approach for the generation of a widely tunable arbitrarily phase-coded microwave signal based on a dual-parallel polarization modulator (DP-PolM) is proposed and demonstrated without using any optical or electrical filter. Two orthogonally polarized ± first-order optical sidebands with suppressed carrier are generated based on the DP-PolM, and their polarization directions are aligned with the two principal axes of the following PolM. Phase coding is implemented at a following PolM driven by an electrical coding signal. The inherent frequency-doubling operation can make the system work at a frequency beyond the operation bandwidth of the DP-PolM and the 90° hybrid. Because no optical or electrical filter is applied, good frequency tunability is realized. An experiment is performed. The generation of phase-coded signals tuning from 10 to 40 GHz with up to 10  Gbit/s coding rates is verified.

Frequency-Quadrupling Optoelectronic Oscillator for Multichannel Upconversion

Photonic microwave multichannel up-conversion based on a polarization-modulated optoelectronic oscillator is proposed and demonstrated. The scheme produces a high-quality local oscillation signal, implements photonic microwave multichannel up-conversion at arbitrary optical wavelengths, and realizes dispersion penalty compensation for multichannel radio over fiber links with different transmission distances in different channels simultaneously. An experiment is carried out. The 50-Mb/s 16 QAM signals at 3.5 and 7.5 GHz are successfully up-converted to 13.436 and 17.436 GHz, and transmitted over 20- and 15-km fibers with dispersion-induced power penalty removed in two independent channels, respectively. The phase noise curves with or without IF signals applied are superimposed, with the value being lower than -110 dBc/Hz at 10-kHz offset.

Wideband signal upconversion and phase shifting based on a frequency tunable optoelectronic oscillator

A frequency-quadrupling dual-loop optoelectronic oscillator (OEO) is proposed and demonstrated by two cascaded polarization modulators. The introduction of frequency quadrupling to the proposed OEO requires no optical filtering, which not only increases the maximal achievable frequency by four times, but also enables powerful optical signal processing functions. An experiment is carried out. A high-quality millimeter-wave signal at 39.75 GHz is generated using low-frequency devices. Photonic microwave upconversion at two wavelength channels is also demonstrated on the basis of the proposed frequency-quadrupling OEO.

Wavelength-Division Multiplexed Fiber-Connected Sensor Network for SLource Localization

Abstract. A wideband signal upconversion and phase shifting scheme based on a frequency tunable optoelectronic oscillator (OEO) are proposed and demonstrated. The OEO performs simultaneously tunable high-quality local oscillator (LO) signal generation, wideband frequency upconversion, and phase shifting within the whole 2π range. With the generated LO tuning from 9.549 to 11.655 GHz, wideband square signals are successfully upconverted to the X band. The phase of the upconverted signal is tuned from 0 to 360 deg. The phase noise of the oscillation signal is about −104  dBc/Hz at 10 kHz offset with or without the injected baseband signal.

Tunable up-converting optoelectronic oscillator based on Stimulated Brillouin Scattering

A fiber-connected source localization sensor network based on optical wavelength-division multiplexing technology is proposed and demonstrated. Thanks to the wavelength-division multiplexed architecture, the signals from the emitter received by different sensors can be identified by different optical carriers, and no clock synchronization or parameter estimation is required at the sensor nodes, which greatly simplifies the entire system. Also, since the received signals are separated in the wavelength domain, the proposed system is suitable for both pulsed and nonpulsed signal source localization, independent of the format of the emitted signal. A proof-of-concept experiment for two-dimensional localization of a wireless fidelity signal is demonstrated. Spatial resolution of less than 17 cm is achieved.

Length measurement of long optical fiber with sub-millimeter resolution

A widely tunable up-converting optoelectronic-oscillator (OEO) based on Stimulated Brillouin Scattering is proposed and demonstrated, which can convert a low-quality and low-frequency IF signal to a high-quality and high-frequency signal without introducing any high-Q electrical filter. Low-phase-noise microwave signals from 10.15 to 42.15 GHz are experimentally generated.

Ultrahigh-resolution and wideband optical vector analysis for arbitrary responses

Knowing the exact length of long optical fiber is of great importance to interferometry-based optical sensors, fiber-connected antenna arrays and other microwave photonic applications. This paper reviews recent efforts on long optical fiber length measurement with sub-millimeter resolution, including optical time domain reflectometers, optical frequency domain reflectometers, and optical backscatter reflectometers based on microwave frequency sweeping. Techniques to improve the measurement resolution and to reduce the measurement error are discussed.