A dual loop optoelectronic oscillator (OEO) is able to effectively suppress the sidemodes in each single loop. In this paper, a dual-loop OEO scheme reported. By utilizing polarization-beam splitter and combiner, two loops are directly joined optical domain without adding any active electrical device. The laser's phase-to-intensity noise discussed. We present free-running experimental results, which show phase of -109 dBc/Hz at 10kHz away from carrier (12 GHz) Q value 10 <sup...

Abstract In order to explore high efficiency microwave absorption materials, heteronanostructured Co@carbon nanotubes-graphene (Co@CNTs-G) ternary hybrids were designed and produced through catalytic decomposition of acetylene at the temperature (400, 450, 500 550 °C) over Co 3 O 4 /reduced graphene oxide (Co /RGO). By regulating reaction temperatures, different CNT contents Co@CNTs-G could be synthesized. The investigations indicated that as-prepared exhibited excellent properties, their...

Abstract In order to clearly understand the intrinsic microwave absorption properties of carbon nanomaterials, we proposed an efficient strategy synthesize high purity metal-free nanotubes (CNTs) over water-soluble K 2 CO 3 particles through chemical vapor decomposition and water-washing process. The comparison results indicated leftover catalyst caused negative effects in CNTs, while enhanced performance could be observed CNT sample. Moreover, that tuned by content. Therefore, provided a...

A new photonic approach of microwave waveform generator based on time-domain synthesis is proposed and experimentally demonstrated, in which two single-drive Mach-Zehnder modulators biased at quadrature point are severed as optical pulse carvers various waveforms can be generated by carving overlapping field envelopes. The theoretical analysis simulation developed. In experiment, a square with 50% duty cycle, triangular full sawtooth (or reversed-sawtooth) cycle generated. Furthermore,...

Resistive devices composed of one-dimensional nanostructures are promising candidates for the next generation gas sensors. However, large-scale fabrication nanowires is still challenging, which restricts commercialization such devices. Here, we report a highly efficient and facile approach to fabricating poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanowire chemiresistive sensors by nanoscale soft lithography. Well-defined sub-100 nm fabricated on silicon substrate,...

A multiband bandpass microwave photonic filter (MPF) whose passband number and position can be selected is theoretically analyzed experimentally demonstrated. The proposed MPF based on a wide-band optical source (WBOS) two-order high-birefringence fiber loop mirror (HB-FLM), which serves as slicing filter. Two segments of (HBF) with the lengths 3 m 6 are used in HB-FLM, three typical spectral periods or their combinations independently achieved by simply adjusting polarization controllers...

In this paper, α-Fe2O3 nanoparticles (NPs)-reduced graphene oxide (RGO), α-FeOOH nanorods (NRs)-RGO and porous NRs-RGO could be selectively synthesized by hydrothermal method. The investigations indicated that the obtained NPs, NRs were either attached on surface of RGO sheets or coated uniformly sheets. And as-prepared nanohybrids exhibited excellent microwave absorption performance, which was proved to ascribed quarter-wavelength matching model. optimum reflection loss (RL) values for...

A new photonic scheme for various waveforms generation has been proposed and demonstrated. In the scheme, two cascaded single-drive LiNbO3 Mach-Zehnder modulators serve as pulse shaper polarization-dependent character of is fully exploited utilized. By arranging polarization states incident light, different spectra are achieved on orthogonal components respectively. Finally, desired can be obtained by superimposing photocurrents signals a photodetector. The detailed theoretical analyses...

A compact optical magnetic field sensor based on a fiber laser oscillator circuit merged with Sagnac loop that contains polarization-maintaining (PMF) and magnetostrictive rod is proposed. The combination of the PMF-Sagnac oscillation significantly increases signal-to-noise ratio reflection spectrum in system, which mixed includes interference fringes lasers. For proposed an erbium-doped amplifier used to provide gain, dispersion compensating compensate for PMF inserted as microwave filter,...

This paper proposes a low-frequency acoustic sensing scheme based on an in-fiber Mach-Zehnder interferometer structure. The structure utilizes the refractive index difference between fiber core and cladding, forming miniature through fusion splicing of specialty optical fibers in multi-mode-ultra-high numerical aperture-multi-mode configuration. design achieves modal recombination cladding modes, thereby effectively enhancing bending sensitivity. is then combined with polyethylene...

In this paper, a scheme for generating high-quality tunable microwave-frequency combs (MFCs) is proposed. The proposed based on an initially non-flat MFC generated by directly modulated laser operating in gain-switching status. Filtering operations are used to increase the flatness of MFC. Concretely, employing optical bandpass filter and two-tap negative-coefficient microwave photonic filter, significantly optimized. experiment, MFCs with adjustable comb spacing from 0.5 GHz 1.6 bandwidths...

The regeneration of 10 Gbit/s differential phase shift keying (DPSK) signals in a saturated fiber optic parametric amplifier (FOPA) acting as an optical intensity regenerator is investigated. properties are investigated amplitude and separately by means coherent detection constellation diagram analysis. A significant reduction the fluctuations observed measured signal-to-noise ratio (SNR) after DPSK demodulation increased up to dB. However, from analysis it found that FOPA introduces noise...

In this paper, we investigate the physical layer security (PLS) for a multiple-input single-output (MISO) non-orthogonal multiple access (NOMA) visible light communication (VLC) system, whose information is intercepted by collusive eavesdroppers. For case of known eavesdroppers' locations, precoding scheme proposed to maximize secrecy capacity system suppressing rate Then extend unknown locations. Specifically, artificial noise introduced in further suppress average To solve non-convex...

We propose a new injection-locked optoelectronic oscillator (OEO) which is locked by low frequency RF signal and without adding high speed devices. From modulated optical carrier, the injection-locking effect in Fabry-Pérot laser diode able to generate selectively amplify one order harmonic component, subsequently injected into single-loop OEO lock of oscillation modes. This process can improve quality simultaneously implement single-mode with precise frequency. In experiment demonstration,...

We propose and demonstrate a new photonic approach for triangular waveform generation. Based on an optical signal with sinusoidal envelope, injection-locking process in distributed-feedback semiconductor laser diode is employed to carry out the desired harmonic generation, then tailored synthesized by superimposition of these signals proper power ratio time delay. In this method, conventional spectral line manipulating transferred individual envelope control, which reduces technical...

Low dimension poly(3,4-ethylenedioxythiophene) poly (styrenesulfonate) (PEDOT: PSS) has been applied as resistor-type devices for temperature sensing applications. However, their response speed and thermal sensitivity is still not good enough practical application. In this work, we proposed a new strategy to improve the performance of PEDOT: PSS by combined micro/nano confinement materials doping. The effect carefully studied fabricating different sized micro/nanowires through low-cost...

Flat optical frequency comb (OFC) can be generated by using single phase modulator (PM), where combined harmonics are applied to drive the PM. However, number of lines and flatness OFC limited under this scheme. In work, we use cascaded PMs with generate flat OFC. The optimized phases modulation indices in terms amplitudes for each harmonic obtained solving optimization problem minimize fluctuation a certain lines. Both simulation experiment carried out evaluate feasibility proposed...

We propose a weak radio frequency (RF) signal detection scheme based on single-mode optoelectronic oscillator (OEO). In this scheme, the phenomenon of injection locking is avoided by using structure phase-locked loop (PLL), which guarantees that OEO works under quasi-locked condition. The PLL also stabilizes gain provided to RF detection. Consequently, maximum 59.49 dB and sensitivity −120 dBm.

All-optical manipulation of signals carried by lightwaves is attractive because controlling the light directly can be more efficient, allows a multitude signal formats, and also prove most cost effective. We implemented novel scheme for ultrafast optical switching using very small control energy that relies on use saturated fiber-optic parametric amplifier. Approximately 19 aJ (150 photons) pulse was needed 50% extinction which three to four orders magnitude smaller than in other all-optical...