Multifunctional photonic integrated circuit for diverse microwave signal generation, transmission and processing

Microwave photonics (MWP) studies the interaction between microwave and optical waves for the generation, transmission and processing of microwave signals (i.e., three key domains), taking advantages of broad bandwidth and low loss offered by modern photonics. Integrated MWP using photonic integrated circuits (PICs) can reach a compact, reliable and green implementation. Most PICs, however, are recently developed to perform one or more functions restricted inside a single domain. In this paper, as highly desired, a multifunctional PIC is proposed to cover the three key domains. The PIC is fabricated on InP platform by monolithically integrating four laser diodes and two modulators. Using the multifunctional PIC, seven fundamental functions across microwave signal generation, transmission and processing are demonstrated experimentally. Outdoor field trials for electromagnetic environment surveillance along an in-service high-speed railway are also performed. The success to such a PIC marks a key step forward for practical and massive MWP implementations.Comment: 17 page

A 160Gb/s (4x40) WDM O-band Tx subassembly using a 4-ch array of silicon rings co-packaged with a SiGe BiCMOS IC driver

We present a 400 (8×50) Gb/s-capable RM-based Si-photonic WDM O-band TxRx with 1.17nm channel spacing for high-speed optical interconnects and demonstrate successful 50Gb/s-NRZ TxRx operation achieving a ~4.5dB Tx extinction ratio under 2.15Vpp drive

4-channel 200 Gb/s WDM O-band silicon photonic transceiver sub-assembly

We demonstrate a 200G capable WDM O-band optical transceiver comprising a 4-element array of Silicon Photonics ring modulators (RM) and Ge photodiodes (PD) co-packaged with a SiGe BiCMOS integrated driver and a SiGe transimpedance amplifier (TIA) chip. A 4 x 50 Gb/s data modulation experiment revealed an average extinction ratio (ER) of 3.17 dB, with the transmitter exhibiting a total energy efficiency of 2 pJ/bit. Data reception has been experimentally validated at 50 Gb/s per lane, achieving an interpolated 10E-12 bit error rate (BER) for an input optical modulation amplitude (OMA) of -9.5 dBm and a power efficiency of 2.2 pJ/bit, yielding a total power efficiency of 4.2 pJ/bit for the transceiver, including heater tuning requirements. This electro-optic subassembly provides the highest aggregate data-rate among O-band RM-based silicon photonic transceiver implementations, highlighting its potential for next generation WDM Ethernet transceivers. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automatic Tuning of Silicon Photonics Millimeter-Wave Transceivers Building Blocks

Today, continuously growing wireless traffic have guided the progress in the wireless communication systems. Now, evolution towards next generation (5G) wireless communication systems are actively researched to accommodate expanding future data traffic. As one of the most promising candidates, integrating photonic devices in to the existing wireless system is considered to improve the performance of the systems. Emerging silicon photonic integrated circuits lead this integration more practically, and open new possibilities to the future communication systems. In this dissertation, the development of the electrical wireless communication systems are briefly explained. Also, development of the microwave photonics and silicon photonics are described to understand the possibility of the hybrid SiP integrated wireless communication systems. A limitation of the current electrical wireless systems are addressed, and hybrid integrated mm-wave silicon photonic receiver, and silicon photonic beamforming transmitter are proposed and analyzed in system level. In the proposed mm-wave silicon photonic receiver has 4th order pole-zero silicon photonic filter in the system. Photonic devices are vulnerable to the process and temperature variations. It requires manual calibration, which is expensive, time consuming, and prone to human errors. Therefore, precise automatic calibration solution with modified silicon photonic filter structure is proposed and demonstrated. This dissertation demonstrates fully automatic tuning of silicon photonic all-pass filter (APF)-based pole/zero filters using a monitor-based tuning method that calibrates the initial response by controlling each pole and zero individually via micro-heaters. The proposed tuning approach calibrates severely degraded initial responses to the designed elliptic filter shapes and allows for automatic bandwidth and center frequency reconfiguration of these filters. This algorithm is demonstrated on 2nd- and 4th-order filters fabricated in a standard silicon photonics foundry process. After the initial calibration, only 300ms is required to reconfigure a filter to a different center frequency. Thermal crosstalk between the micro-heaters is investigated, with substrate thinning demonstrated to suppress this effect and reduce filter calibration to less than half of the original thick substrate times. This fully automatic tuning approach opens the possibility of employing silicon photonic filters in real communication systems. Also, in the proposed beamforming transmitter, true-time delay ring resonator based 1x4 beamforming network is imbedded. A proposed monitor-based tuning method compensates fabrication variations and thermal crosstalk by controlling micro-heaters individually using electrical monitors. The proposed tuning approach successfully demonstrated calibration of OBFN from severely degraded initial responses to well-defined group delay response required for the targeted radiating angle with a range of 60◦ (-30◦ to 30◦ ) in a linear beamforming antenna array. This algorithm is demonstrated on OBFN fabricated in a standard silicon photonics foundry process. The calibrated OBFN operates at 30GHz and provide 2GHz bandwidth. This fully automatic tuning approach opens the possibility of employing silicon OBFN in real wideband mm-wave wireless communication systems by providing robust operating solutions. All the proposed photonic circuits are implemented using the standard silicon photonic technologies, and resulted in several publications in IEEE/OSA Journals and Conferences

Application of Memristors in Microwave Passive Circuits

The recent implementation of the fourth fundamental electric circuit element, the memristor, opened new vistas in many fields of engineering applications. In this paper, we explore several RF/microwave passive circuits that might benefit from the memristor salient characteristics. We consider a power divider, coupled resonator bandpass filters, and a low-reflection quasi-Gaussian lowpass filter with lossy elements. We utilize memristors as configurable linear resistors and we propose memristor-based bandpass filters that feature suppression of parasitic frequency pass bands and widening of the desired rejection band. The simulations are performed in the time domain, using LTspice, and the RF/microwave circuits under consideration are modeled by ideal elements available in LTspice