E. Alkhazraji

Far L-band Single Channel High Speed Downstream Transmission using Injection-locked Quantum-dash Laser for WDM-PON

We demonstrate an externally modulated single channel 64 Gbit/s DP-QPSK transmission based on injectionlocked Fabry-Pérot broadband quantum-dash laser at far L-band ~1621 nm wavelength. A receiver sensitivity of -16.7 dBm has been observed after 10 km SMF transmission, with power penalty of ~2 dB, under the FEC threshold. We also propose that these novel quantum-dash laser diode could be a route towards next generation 100Gbit-PONs as a unified upstream and downstream transmitters.

Tunable Vivaldi antenna design for frequency scanning

In this paper, a tunable antipodal Vivaldi antenna is presented for frequency scanning in UWB applications. The upper and lower patches of tapered slot antenna (TSA) consist of two different gradient edges from which frequency scanning function is obtained. Microstrip line of 50 Ω impedance is used for feeding the antenna. The tuning is achieved by varying the DC biasing of Ferrite substrate. The main beam of the E-plane radiation patterns at single operating frequency of 8 GHz, are -40°, 15 °, and -10 °, respectively, which clearly shows the frequency scanning function of the antenna.

Broadband Lasing Characteristics of a Chirped InAs/InP Quantum-Dash Laser

We investigate the temperature dependent spectral characteristics of an InAs multi-stacked quantum-dash-inwell laser. The multi-stack active medium optical transitions are dispersed by varying the thickness of AlGaInAs barrier layers. The analysis is carried out via a Fabry-Perot 700 μm long-cavity laser with a ridge width of 2 μm at different temperatures. A lasing bandwidth of >40 nm is observed at room temperature with total optical power of >150 mW. Moreover, broadening of lasing spectrum is observed with increasing the temperature, due possibly to a thermionic assisted emission and to optical pumping, enabling a full exploitation of the inhomogeneous optical transitions within the active region which indicates an increase in the available states in the active region. Therefore, proper optimization of the multi-stack active medium is required to fully utilize these optical transitions while maintaining high quantum efficiency, and proper bandgap engineering the device structure.

RFID antenna design for circular polarization in UHF band

A miniature half cross dipole antenna for defense and aerospace RFID applications in UHF band is presented. The dipole printed line arms are half crossed shape on top of dielectric substrate backed by reactive impedance surface. The antenna fed by a coaxial cable at the gap separating the dipole arms. Our design is intended to work at 2.42 GHz for RFID readers. The radiation pattern obtained has HPBW of 112, return loss of 22.24 dB and 90 MHz bandwidth.