Pengxiao Li

Photonic-assisted multi-channel compressive sampling based on effective time delay pattern

In this paper, a photonic-assisted multi-channel compressive sampling scheme is proposed with one pseudo-random binary sequence (PRBS) source and Wavelength Division Multiplexing-based time delay. Meanwhile, the restricted isometry property of sensing matrix determined by the optimized time delay pattern is analyzed. In experiment, a four-channel photonic-assisted system with 5-GHz bandwidth was set up, where four-channel PRBS signals were generated by adding fiber-induced constant time delays to four-wavelength modulated PRBS signal, and a signal composed of twenty tones was recovered faithfully with four analog-to-digital converters (ADCs) with only 120-MHz-bandwidth.

Gigabit/s Photonic Generation, Modulation, and Transmission for a Reconfigurable Impulse Radio UWB Over Fiber System

We propose and demonstrate a flexible and high-speed impulse radio ultrawideband (IR-UWB) over fiber system using various modulation schemes. Two kinds of fully Federal Communication Commission (FCC) compliant UWB pulses are produced, which is based on the incoherent summation of multiple monocycle pulses with inverse polarities, proper time delays, and different weights. Theoretically, their spectral power efficiency can achieve 33.9% and 47.4%, respectively, which is much higher than that of the conventional monocycle and doublet pulses. A good agreement between the theoretical and experimental results for the generation of designed UWB pulses is also observed. Moreover, electrically reconfigurable multiple modulation formats such as on-off keying (OOK) modulation, binary phase shift keying (BPSK) modulation, pulse shape modulation (PSM), and pulse position modulation (PPM) are implemented experimentally. Furthermore, the UWB signals with OOK, BPSK, and PPM are transmitted over a combined wired (single-mode fiber) and wireless link. The transmission performance of the newly generated UWB pulses is then evaluated by electrical spectra, eye diagrams, and bit-error-rate measurements. For all the modulation formats, a forward-error-correction (FEC)-limit error-free operation is obtained, and the power penalties of transmission are less than 1 dB.

Silicon-on-insulator narrow-passband filter based on cascaded MZIs incorporating enhanced FSR for downconverting analog photonic links

A silicon-on-insulator (SOI) narrow-passband filter based on cascaded Mach-Zehnder interferometers (MZIs) is theoretically simulated and experimentally demonstrated, indicating that the free spectral range (FSR) of the proposed filter can be significantly enlarged by increasing the number of the MZI stages. A filter using three-stage cascaded MZIs structure is successfully realized in the experiment and a 3-dB bandwidth of about 1.536 GHz and FSR about 13.5 GHz have been achieved. The performance of a downconverting analog photonic link (APL) employing the designed filter for microwave signal processing is also measured and a spurious free dynamic range (SFDR) as high as 104.1dB-Hz(2/3) is observed.

An all-fiber continuously time-dispersion-tuned picosecond optical parametric oscillator at 1 μm region

We report the experimental demonstration of a fully fiber-integrated picosecond optical parametric oscillator. The gain is provided by a 50-meters homemade photonic crystal fiber in the ring cavity. A time-dispersion-tuned technique is used to allow the oscillator to select the oscillating wavelength adaptively and synchronize with the pump pulse train. The output wavelength of the oscillator can be continuously tuned from 988 to 1046 nm and from 1085 to 1151 nm by adjusting the pump wavelength and the time-dispersion-tuned technique simultaneously.

Photonic Generation and Transmission of 2-Gbit/s Power-Efficient IR-UWB Signals Employing an Electro-Optic Phase Modulator

We experimentally demonstrate a power-efficient ultrawideband (UWB) generation scheme using an electro-optic phase modulator. The generated UWB pulses are fully Federal Communication Commission compliant with high power efficiency of 52.6%. Furthermore, 2-Gbit/s on-off keying modulated modified UWB triplet signals are transmitted over 20 km optical fiber link without any obvious spectra or pulse shape distortions, and error-free transmission is achieved with power penalties less than 1.5 dB.

Linearized photonic if downconversion of analog microwave signals based on balanced detection and digital signal post-processing

A novel linearized photonic downconversion technique based on balanced detection and digital signal post-processing is proposed and experimentally demonstrated. The overall system performance benefits from carrier suppression operation and balanced detection. The dynamic ranges of both the X- and K-band links are also investigated. After compensated in the digital domain, the downconverted IMD3 components are significantly suppressed by more than 21 dB, corresponding to about 10 dB and 7.4 dB improvement in SFDR for the X- and K-band analog microwave photonic link, respectively.

Photonic Downconversion and Linearization of Microwave Signals from the

A linearized photonic radio frequency (RF)-to-intermediate frequency (IF) conversion system is proposed and experimentally demonstrated based on balanced detection and digital signal postcompensation. The optical carrier suppression and remodulation scheme is employed to significantly reduce the local oscillator frequency requirements and common mode optical phase noises. Photonic IF downconversion is enabled by using a reconfigurable multiport optical processor and balanced coherent detection of the spectrally separated lower and upper first-order sidebands of the phase modulated signals. Moreover, the digital linearization technique is used to suppress the third-order intermodulation components by more than 21 dB and an improvement of the spurious free dynamic range as large as 7 dB for RF signals ranging from 8–20 GHz is also achieved.

X

Analog photonic link (APL) is attractive for its potential high performance of larger dynamic range, tunability, and immunity to electromagnetic interference (EMI). An APL based on the Aulter-Townes splitting (ATS)-effect-induced dual-band filter for optical carrier suppression (OCS) and the SOI signal processor has been proposed and experimentally demonstrated. The bandwidths of the two passbands are approximately 780 MHz, and the interval could be tuned from 8 GHz to more than 80 GHz in simulation. The extinction ratio is larger than 20 dB, which can provide a 20-dB suppression of the optical carrier and higher order sidebands to obtain clean optical carrier and local oscillator (LO) for modulation and down-conversion. The down-conversion APL based on the proposed dual-band OCS filter at X-band has been presented, and the spurious free dynamic range (SFDR) of the link is measured to be as high as 102.2  dB-Hz(2/3).

- to

A compact quality factor (Q)-enhanced bandpass filter based on the electromagnetically induced transparency (EIT)-like effect between two-ring resonators was proposed and experimental demonstrated. The enhancement in Q can be 2-3 orders of magnitude compared to the single ring bandpass filter, and a 27 times enhanced bandpass filter with a bandwidth of approximately 4.8 GHz was successfully realized. A downconversion analog photonic link (APL) based on the proposed filter has been presented and the spurious free dynamic range of the link was as high as 103.9 dB-Hz(2/3).

K\!

We firstly propose one system configuration for generating three kinds of modulation formats used in high-speed ultra-wide-band (UWB) over fiber application. 2Gbps UWB signal transmission over 20km single mode fiber without any compensation is experimentally demonstrated.