High-speed photonic power-efficient ultra-wideband transceiver based on multiple PM-IM conversions

We experimentally demonstrate a novel photonic ultra-wideband (UWB) transceiver with pulse spectral efficiency of 50.97% and transmission speed up to 3.125 Gb/s. The UWB generator only consists of a highly nonlinear fiber (HNLF) and a commercial arrayed-waveguide grating (AWG). By using the concept of multiple cross-phase modulation in the HNLF and multiple phase modulation to intensity modulation conversions in the AWG, a power-efficient UWB pulse is combined with incoherent summation of two asymmetric monocycle pulses with inverted polarities. Benefiting from the ultra-fast response of fiber nonlinearities in the HNLF, onoff keying encoded UWB signals generated at 781.25 Mb/s, 1.5625 Gb/s, and 3.125 Gb/s are all error-free transmitted through a 22.5-km single-mode fiber (SMF) with power penalties lower than 1 dB. The bit-error rate is directly measured on down-converted baseband signals by using optical full rectification and electrical low-pass filtering technologies. The measured electrical spectra before and after 22.5-km SMF link transmission both fully comply with the spectral mask specified by the U.S. Federal Communications Commission (FCC) without power attenuation. © 2006 IEEE.published_or_final_versio

Ultrawideband Systems and Networks: Beyond C + L-Band

In the evolution of optical networks, enhancement of spectral efficiency (SE) enhancement has been the most cost-efficient and thus the main driver for capacity enhancementincrease for decades. As a result, the development of optical transport systems has been focused on the C -and L -bands, where silica optical fiber exhibits the lowest attenuation, and erbium-doped fiber amplifiers provide an efficient solution forto compensatinge for the optical loss. With a gradual maturity in the SE growth, however, the extension of the optical bandwidth beyond the C + L -band is expected to play a significant role in the future capacity upgrades of optical networks and, thus, attracting increasing research interests. In this article, we discuss the merits and challenges of ultrawideband optical transport systems and networks beyond conventional bands

Ultra-wideband CMOS power amplifier for wireless body area network applications: a review

A survey on ultra-wideband complementary metal-oxide semiconductor (CMOS) power amplifiers for wireless body area network (WBAN) applications is presented in this paper. Formidable growth in the CMOS integrated circuits technology enhances the development in biomedical manufacture. WBAN is a promising mechanism that collects essential data from wearable sensors connected to the network and transmitted it wirelessly to a central patient monitoring station. The ultra-wideband (UWB) technology exploits the frequency band from 3.1 to 10.6 GHz and provides no interference to other communication systems, low power consumption, low-radiated power, and high data rate. These features permit it to be compatible with medical applications. The demand target is to have one transceiver integrated circuit (IC) for WBAN applications, consequently, UWB is utilized to decrease the hardware complexity. The power amplifier (PA) is the common electronic device that employing in the UWB transmitter to boost the input power to the desired output power and then feed it to the antenna of the transmitter. The advance in the design and implementation of ultra-wideband CMOS power amplifiers enhances the performance of the UWB-transceivers for WBAN applications. A review of recently published CMOS PA designs is reported in this paper with comparison tables listing wideband power amplifiers' performance

Devices and Fibers for Ultrawideband Optical Communications

Wavelength-division multiplexing (WDM) has historically enabled the increase in the capacity of optical systems by progressively populating the existing optical bandwidth of erbium-doped fiber amplifiers (EDFAs) in the C-band. Nowadays, the number of channels—needed in optical systems—is approaching the maximum capacity of standard C-band EDFAs. As a result, the industry worked on novel approaches, such as the use of multicore fibers, the extension of the available spectrum of the C-band EDFAs, and the development of transmission systems covering C- and L-bands and beyond. In the context of continuous traffic growth, ultrawideband (UWB) WDM transmission systems appear as a promising technology to leverage the bandwidth of already deployed optical fiber infrastructure and sustain the traffic demand for the years to come. Since the pioneering demonstrations of UWB transmission a few years ago, long strides have been taken toward UWB technologies. In this review article, we discuss how the most recent advances in the design and fabrication of enabling devices, such as lasers, amplifiers, optical switches, and modulators, have improved the performance of UWB systems, paving the way to turn research demonstrations into future products. In addition, we also report on the advances in UWB optical fibers, such as the recently introduced nested antiresonant nodeless fibers (NANFs), whose future implementations could potentially provide up to 300-nm-wide bandwidth at less than 0.2 dB/km loss

Broadband High-Efficiency Power Amplifier with Quasi-Elliptic Low-Pass Response

© 2013 IEEE. This paper presents a broadband high-efficiency harmonic-tuned power amplifier (PA) with quasi-elliptic low-pass responses. A combination of continuous Class-F-1 and extended continuous Class-F PA modes is employed to significantly expand the design space. A quasi-elliptic low-pass matching network is proposed, which can realize a broadband impedance matching in the predefined optimal impedance region desired by the combination of PA modes. Furthermore, two transmission zeros are generated near the passband, exhibiting high skirt selectivity and providing rapid impedance transition from the passband to the stopband. A wide stopband covering up to the third harmonic is achieved which shows good harmonic suppression. Design procedures of the proposed broadband PA are presented. To verify the proposed methodology, the broadband PA is fabricated and measured. The implemented PA achieves a bandwidth of 145.2% from 0.5 to 3.15 GHz. Over this frequency range, the drain efficiency is measured as 58-74.9% with the output power of greater than 39.03 dBm and a large signal gain ranging from 8.43 to 15.67 dB. A wide stopband is realized from 3.4 to 10 GHz, showing excellent quasi-elliptic low-pass responses. The measured adjacent leakage ratios (ACLRs) using a 20-MHz LTE signal with digital pre-distortion are below -45.06 dBc

Extended Feedback System for Coupled Sub-THz Gyro-Devices to Provide New Regimes of Operation

A new type of high-power pulsed source in the millimeter and submillimeter frequency range, utilizing the method of passive mode locking, was proposed in 2015 by the Institute of Applied Physics (IAP-RAS) in Nizhny Novgorod. This principle, well known from laser physics, allows the generation of a periodic series of powerful, coherent, ultrashort pulses. In the millimeter and submillimeter wavelength range, this can be realized using an amplifier and a saturable absorber coupled in a feedback loop. For the coupling of the two devices, a sophisticated feedback system is required. Such a system, based on simple overmoded waveguide components, was previously proposed by the authors. The present article shows how the proposed feedback system can be extended, allowing for a wide range of possible operation regimes for two coupled gyro-devices. Particularly noteworthy is the application of the modified feedback system for the realization of a two-stage amplifier in the subterahertz (sub-THz) range. Furthermore, it seems to be possible to use two helical gyro-devices coupled in the proposed way as a source of coherent pulses, as a free-running or locked continuous wave (CW) source, and as a two-stage amplifier. In all cases, no design changes of the feedback system are required

Radio over fibre distribution systems for ultra-wide band and millimetre wave applications

Short range wireless technology such as ultra-wideband (UWB) and 60 GHz millimetre wave (mm-wave) play a key role for wireless connectivity in indoor home, office environment or large enclosed public areas. UWB has been allocated at the frequency band 3.1-10.6 GHz with an emission power below -41.3 dBm. Mm-wave signals around 60 GHz have also attracted much attention to support high-speed data for short range wireless applications. The wide bandwidth and high allowable transmit power at 60 GHz enable multi-Gbps wireless transmission over typical indoor distances. Radio-over-fibre (RoF) systems are used to extend the propagation distance of both UWB and mm-wave signals over hundred of meters inside a building. UWB or mm-wave signals over fibre can be generated first at the central office before being distributed to the remote access points through optical fibre. In this work, we investigate two new techniques to generate and distribute UWB signals. These techniques are based on generating Gaussian pulse position modulation (PPM) using a gain switched laser (GSL). The simulation and experimental results have been carried out to show the suitability of employing gain switching in UWB over fibre systems (UWBoF) to develop a reliable, simple, and low cost technique for distributing UWB pulses. The second part of this work proposes two configurations for optical mm-wave generation and transmission of 3 Gbps downstream data based on GSL. We investigate the distribution of these two methods over fibre with wireless link, and demonstrate the system simplicity and cost efficiency for mm-wave over fibre systems. Both configurations are simulated to verify our obtained results and show system performance at higher bit rates. In the third part, we generate phase modulated mm-waves by using an external injection of a modulated light source into GSL. The performance of this system is experimentally investigated and simulated for different fiber links