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In this paper, we discuss the impact of finite extinction ratio of modulator on the photonic time stretch (PTS) system and address concise expressions of all harmonics for modulation with a single arm Mach-Zehnder modulator (MZM) and a push pull MZM separately. The 3dB bandwidth of the system is investigated based on the theoretical analysis. Both experimental and numerical results are presented to...
An amplified feedback DFB laser with extended modulation bandwidth is experimentally demonstrated in this paper. All the three sections of laser cavity, including DFB section, phase section and amplified feedback section, have the same active layer, which can avoid the butt-joint re-growth process. The gratings in both DFB section and amplified feedback section are fabricated by the Reconstruction...
In the context of the augmented demand for high capacity and uninterrupted communication links, radio-over-fiber technology provides advantage in terms of reduced power dissipation and broad operational frequency bandwidth. In such a link, a vertical-cavity surface-emitting laser plays an important role as an optical source, due to its real-time RF modulation capability, and consequently, the understanding...
An IR-UWB indoor positioning is proposed in the paper that combines the algorithm of Time-of-Arrival (TOA) and band-gap modulations. The positioning is referenced by three UWB locators that have different band-gap and deployed in a right triangle. An object can determine its position by identifying pulse backscattered on locators and each locator's signatures through recognizing the exact segment...
An integrated capacitance sensor interface is proposed with three programmable gain stages to measure femto-farad capacitance. The capacitance sensor interface is a differential measurement set-up to measure the change in capacitance over a fixed nominal capacitance. The programmable gain stages are used to change the gain settings to operate for a wide-range capacitance measurement. The implemented...
This paper presents a sub-pA current read-out interface that consists of a series connection of a low-noise current amplifier and a second-order continuous-time Delta-Sigma modulator. Contrary to the approach to the current amplification by means of a series connection of a charge integrator and differentiator, no reset and thus no interruption of the current-to-digital conversion needs to be performed...
This paper presents a low-noise, low-power CMOS interface circuit for MEMS gyroscope readout ASIC. Our interface circuit is composed of a continuous-time delta-sigma modulator, an anti-aliasing filter, and an on-chip reference generator. By using a low-pass delta-sigma modulator instead of a band-pass delta-sigma modulator, a frequency matching circuit is unnecessary which enables wideband operation...
In this paper, the state of the art and progress towards building a complete plasmonic front-end for Terahertz communications is described. The discussed system architecture, whose components rely on the properties of graphene and III/V semiconductors, is able to generate, modulate, radiate and, reciprocally, detect and demodulate THz signals with multi-GHz bandwidths, needed for next generation communication...
This paper focuses on the design and analysis of multi-stage noise-shaping (MASH) sigma-delta modulators. Fundamentals and properties of MASH modulators are discussed. A detailed methodology on analyzing continuous-time MASH (CT-MASH) modulator based on the impulse invariant transformation is also described. Two fabricated design examples are discussed: a 130 nm CMOS CT-MASH 4-0 employing a digital...
A passive delta-sigma ADC with a voltage-controlled-oscillator (VCO) quantizer is presented. By employing the VCO quantizer, a single-bit quantizer is replaced with a multi-bit quantizer while an extra order of noise-shaping was provided. The proposed architecture does not need very large capacitors as compared to the conventional passive delta-sigma ADC. Furthermore, it also does not require external...
Optical Network Virtualization has gained attention in recent years mainly from industry due to its direct application to Optical Data Centers. One of the main challenges involved in optical virtualization deals with the efficient mapping of virtual resources onto physical resources, specially when considering the intrinsic constraints of the elastic optical layer based on O-OFDM such as optical spectrum...
Low Power Wide Area Networks (LPWAN) are expected to interconnect a high number of simple and inexpensive devices. The ability to control transmission parameters including modulation scheme and output power, enables reduction of the deployment costs, improvement of the network reliability, in terms of error performance under suboptimal conditions, and could contribute to the reduction of the maintenance...
We present the first waveguide electro-absorption modulator in germanium-on-silicon material platform at 3.8 μm wavelength, based on free-carrier injection into a straight waveguide. The fabricated 1 mm long device has modulation depth of >35 dB at 7 V.
Novel technologies based on pulse amplitude modulation (PAM) are studied for a high-speed visible light communication (VLC) system. In this paper, we summarize the latest progress on high-speed PAM-VLC systems including phase shifted Manchester coding, Nyquist filter, weighted pre-equalization, multi-band access, and hybrid time-frequency domain equalization, which supporting VLC high data-rate and...
This article discusses the implementation of a wide band vectorial digital modulator and a tool to evaluate the Bit Error Rate. This modulator is capable of generate a wide band (up to 6.3 MHz) 16-QAM modulation in baseband. A second functionality programmed in the tool and reported in this article evaluates the Bit Error rate in order to measure the received signal quality. Results are validated...
The development of advanced InP-based transmitter PICs of increasing complexity and integrating periodically capacitive-loaded (CL) Travelling Wave Electrode (TWE) Mach-Zehnder modulators is reported and discussed in examples.
In this work, we investigate the performance specifications of the components comprising the suggested intra- and inter-Data Centres (DCs) systems according to DIMENSION project. More specifically, we deal with the performance specifications of the laser sources and the respective modulators. The intra-DC system employs a novel Directly Modulated Laser (DML) grown on Silicon Photonics (SiPh) and targets...
In this paper, various trade-offs for the design of short-range optical interconnects for on-board communication in a high-performance computer (HPC) will be discussed. Energy consumption and bandwidth requirements of the components, which are used for the realization of an optical link in future highly adaptive energy-efficient computers, will be estimated based on the energy consumption and bandwidth...
The Manet or Mobile Ad-Hoc Networks are capable of forming wireless networks with different topologies. The radios which form the network uses a specific band, data rate and frequency. The paper focuses on the implementation of intelligent Mobile Ad-hoc NETwork (iMANET) in which wireless networks are established using reconfigurable radios so that intelligent networks can be formed. The nodes involved...
A high-speed traveling wave electro-absorption modulator based on grapheme-micro fiber is designed. Graphene modulates the optical transmission intensity by changing its fermi level under different applied voltages. Graphene has an extremely high carrier mobility which has a potential electrical bandwidth of 500 GHz. However, the bandwidth of the state-of-art graphene based modulator is limited by...
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