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In order to find out the tradeoff between recovery time and resource overhead when a link failure occurs, we propose a software-defined based fast restoration scheme for elastic optical datacenter networks, called precomputation based restoration path (P-RP). By extending the controller functionality and OpenFlow protocol in software defined networking (SDN) technology, we establish a novel elastic...
The use of spread spectrum underlay signals has been widely proposed in cognitive radio contexts as a means to provide available spectrum for secondary users. Underlay signals are generally transmitted on a minimal interference basis to prevent disruption of the primary user(s). This paper proposes concepts for integrating the use of arbitrary, digitally modulated signals (primary) with time- and...
850-nm vertical-cavity laser diodes with copper-plated heat sinks were fabricated and tested. Vertical-cavity surface-emitting lasers with 10μm aperture diameter and 4μm of electroplated copper demonstrated a maximum −3dB modulation bandwidth of more than 16GHz and a resonance frequency of more than 11GHz at bias current of only 5.4mA, which correspond to a bias current density of only 7.5kA/cm2....
This paper presents a fully differential high-resolution analog interface circuit to apply in an inertial navigation system. By integrating an anti-aliasing filter and a second order sigma-delta modulator into a single chip, the interface circuit can achieve high-resolution with low power consumption. The prototype fabricated in a 0.25 µm CMOS process achieves a dynamic range (DR) of 94 dB, a SNDR...
We investigate the problem of dynamically routing and spectrum assignment for advance reservation anycast requests using a novel algorithm called Delayed Spectrum Allocation (DSA). We evaluate the flexible window STSD (Demands that specify start-time and duration) to further improve request blocking. Through extensive simulation results we show that anycast with flexible STSD using DSA approach can...
As the number of wireless devices, services, communication standards and respective modes of operation rapidly grows, the design of reconfigurable digital baseband processing systems for radio devices becomes more important and challenging. Long Term Evolution (LTE) is among the most relevant wireless systems in 4G communications and its waveform is OFDM-based. According to the LTE mode of operation,...
This paper presents a 40 Gbps micro-ring modulator driver IC implemented in a 130nm SiGe BiCMOS technology providing a fT,max of 250GHz. The proposed bandwidth-optimized driver IC achieves 2Vppd output signal swing required for the integrated high-impedance silicon photonics ring modulator or 1Vppd when differentially terminated with 100Ω. The complete driver including input termination and biasing...
The increasing demand for wider bandwidth in the current wireless networks and the need to work simultaneously with different networks impose many design challenges for power amplifiers (PA) design and the digital predistortion (DPD) in many aspects. The analog-to-digital converter (ADC) sampling speed for conventional DPD has to be several times the original signal bandwidth in order to cover the...
Essentially, a software-defined radio (SDR) receiver can be described as a radio divided into two different parts. One, the analog front-end, down-converts and samples an RF wireless signal. The other, a back-end implemented in software or digital hardware, processes the samples and recovers the transmitted information, whether it is audio, video, instrumentation data, or whatever else. An SDR transmitter...
The LTE-Advanced and its related market factors present many challenges for the RF power amplifier (PA) and front end designs. This paper reviews some of the emerging techniques such as dynamic supply voltage modulation, reconfigurable PA, FET stacking and power combining to solve these challenges for silicon based PAs. These techniques with advanced CMOS and SiGe technologies can benefit the future...
An EUTRAN offers Multi-Point connectivity from base station (eNB) toward the UE for reliable connection under mobility. This enhances the user experience with committed throughput. Radio resource allocation is a complex arrangement of resources in multiuser scenario, and it became more cumbersome if UE offer optional or alternative path to connect the network. Generally in network radio resources...
This paper presents an efficient way to implement On-Off keying (OOK) modulation for visible light communication (VLC) while keeping high power efficiency of illumination function. We analyze the impact of the modulation on output current variations controlled by a buck regulator. The inductor used in the power supply needs to be optimized for a low current ripple during long sequences of 1 or 0 while...
OFDM is one of the most popular used multiplexing techniques for 4G communication environment. OFDM increases the bandwidth and efficiency of the system, but it makes system too complex also. The one of the major disadvantage of this system is its high PAPR, which results some restrictions in its implementation. In this paper an approach for mathematical analysis of PAPR based on OFDM will be given.
Mach-Zehnder electro-optic modulators with MQW cores and series connected arms are fabricated using substrate removal techniques. Under 0 V bias is 1.69 V, device impedance is 57 Ω and bandwidth is 40 GHz. Device can be operated without bias using a directly connected 50 Ω source.
The properties and performance of CdSSe/ZnS colloidal quantum dot composite materials for use as InGaN LED color converters in visible light communications applications is reported. 500Mb/s optical wireless transmission is demonstrated.
Unintentional modulation (UIM), which is unavoidable and unique to individual emitters, can be used to reliably realize emitter identification. Previous identification methods extract features from either some parts of the signal, ignoring the UIM on the other parts, or immediately the whole signal, resulting in heavy computational loads. In this paper, we take the structure of UIM into consideration,...
High-speed optical transmitters with a flip-chip interconnection were developed. The flip-chip interconnection technique can provide a high modulation bandwidth and low electrical crosstalk. We achieved 8 × 50-Gbit/s simultaneous operation with an EADFB laser array module and 100-Gbit/s operation with an EADFB laser module.
We explain how to optimize the nonlinear spectrum of multi-soliton pulses by considering the practical constraints of transmitter, receiver, and lumped-amplified link. The optimization is applied for the experimental transmission of 2ns soliton pulses with independent on-off keying of 10 eigenvalues over 2000 km of NZ-DSF fiber spans.
III-nitride light emitting diodes (LEDs) have been used for many applications covering the spectrum of ultraviolet (UV) to visible light (VL). Despite of significant improvements on solid-state lighting, LEDs still suffer significant efficiency loss at high carrier density, commonly referred as "efficiency droop" [1]. However, compared to LEDs, laser diodes (LDs) have higher power per chip...
Long wavelength (LW) vertical cavity surface emitting lasers (VCSELs) are important low cost and low power consumption sources for optical interconnects in data centers, sensing and spectroscopy [1,2]. We discuss here the recent progress in the design, fabrication and industrialization of such devices made by using wafer fusion, which allows integration of GaAs-based distributed Bragg reflectors (DBRs)...
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