Hongchen Yu

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.

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.

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

Ultra-broadband radiofrequency (RF) receivers are required in higher frequency-band wireless communications, radar communications or multi-band applications in radio telescopes. Such ultra-broadband receivers are inherently difficult to establish with electronics because of limits in the bandwidth of the devices. Photonic means of RF photonic receivers/frontends can overcome the bandwidth limitation in electrical receivers. One aspect that should be considered is the precise signal processing in the optical domain. Here, a full-band (from the L-band to the W-band) all-optical RF receiver based on the Si3N4 microring filter is proposed and experimentally demonstrated. The resolution and processing range of the filter are lower than 420 MHz and larger than 112.9 GHz (FSR larger than 225.78 GHz), respectively, and the out-band suppression of this filter is greater than 40 dB. The center frequency of the filter can be altered for more than one FSR by tuning the phase-shifter on top of the ring. The performance of the full-band all-optical RF-receiver has been discussed, and the spurious free dynamic range of the receiver from the L-band to the Ka-band (limited by the bandwidth of the modulator in our experiment) has been measured to be larger than 111.6 dB·Hz2/3.

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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).

K\!

Digital signal processing has achieved great success in the field of signal processing over the past several decades. However, as the bandwidth requirement increases, the power consumption and effective number of bits (ENOB) of the analog-to-digital convertor (ADC) have become bottlenecks. One solution is returning to analog and applying microwave photonic technologies, which shows potential for multiband signal processing. In this paper, a programmable integrated analog photonic signal processor based on cascaded Mach-Zehnder interferometers (MZIs) and a channelized filter has been proposed. Different shapes of the signal processor can be acquired for different applications. The highest processing resolution is 143 MHz, and the processing range of the signal processor can be higher than 112.5 GHz. An application of the signal processor for the signal extraction in a radio frequency (RF) photonic frontend operating from L-band to K-band is presented.

-Band

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).

All-Optical Full-Band RF Receiver Based on an Integrated Ultra-High-Q Bandpass Filter

Broadband Radio frequency (RF) photonic front-ends are one of the vital applications of the microwave photonics. A tunable and broadband RF photonic front-end integrating with the optoelectronic oscillator (OEO) based local oscillator has been proposed and experimentally demonstrated, in which only one phase modulator (PM) is employed thanks to the characteristic of the PM. The silicon-on-insulator based narrow-bandwidth band-pass filter is introduced for signal processing. The application condition of the proposed RF photonic front-end has been discussed and the performance of the front-end has also been measured. The SFDR at a frequency of about 7.02 GHz is measured to be 88.6 dB-Hz(2/3).

Analog photonic link based on the Aulter-Townes splitting induced dual-band filter for OCS and the SOI signal processor.

We experimentally demonstrate a line scan microscopic imaging system with 1-D frame rate of 1 GHz, which dramatically exceeds the records before. This technique has potential to capture fast process, especially non-repetitive transient phenomena.

Si 3 N 4 -Based Integrated Optical Analog Signal Processor and Its Application in RF Photonic Frontend

An all-optical orthogonal frequency-division multiplexing (OFDM) demultiplexer based on silicon-on-insulator (SOI) waveguide technology is proposed and experimentally demonstrated. Such an integrated structure performing a discrete Fourier transform (DFT) not only has the advantages of a smaller volume and better stability but can also handle more optical subcarriers by increasing the number of the cascaded Mach-Zehnder interferometer (MZI) stages. An SOI-based eight-channel OFDM demultiplexer has been successfully fabricated with a free spectrum range (FSR) of approximately 64 GHz. Eight-subcarrier optical OFDM signals with non-return-to-zero (NRZ) formats are successfully detected by the proposed demultiplexer after a 30-km fiber-link transmission. The total modulation speed is 64 Gbaud, and the bit error rate (BER) performance of each subcarrier is also measured.