Quantum dot multi-wavelength lasers for Tbit/s coherent communications and 5G wireless networks -INVITED

We will present the design, growth, fabrication, electronic control and packaging of the InAs/InP quantum dot (QD) multi-wavelength lasers (MWLs) developed by AEP of NRC in Canada. Their key technical specifications include L-I-V curves, optical and RF beating spectra, relative intensity noise (RIN), and optical phase noise of each individual wavelength channel, as well as timing jitter are investigated. Data bandwidth transmission capacity of 5.376 Tbit/s and 10.3 Tbit/s respectively in the PAM-4 and 16-QAM modulation formats are demonstrated by only using a single QD MWL chip. We have also developed a novel monolithic InAs/InP QD dual-wavelength (DW) DFB laser as a compact optical beat source to generate millimeter-wave (MMW) signals. Because of using a common cavity, highly coherent and correlated optical modes with optical linewidth as low as 15.83 kHz, spectrally pure MMW signals around 46.8 GHz with a linewidth down to 26.1 kHz were experimentally demonstrated. By using this QD DW-DFB laser, a 1Gbaud (2Gbps) MMW over-fiber transmission link is demonstrated with PAM-4 signals. The results show that the demonstrated device is suitable for high speed high capacity MMW fiber-wireless integrated fronthaul of 5G networks.

An L-band monolithic InAs/InP quantum dot mode-locked laser with femtosecond pulses

We have developed an InAs/InP quantum dot (QD) gain material using a double cap growth procedure and GaP sublayer to tune QDs into the L-band. By using it, a passive L-band mode-locked laser with pulse duration of 445 fs at the repetition rate of 46 GHz was demonstrated. The 3-dB linewidth of the RF spectrum is less than 100 KHz. The lasing threshold injection current is 24 mA with an external differential quantum efficiency of 22% and an average output power of 27 mW. The relationship between pulse duration and 3-dB spectral bandwidth as a function of injection current was investigated.

Studies on antioxidative activity of some C-glycosylflavones

Ten flavonoid C-glycosyl derivatives: orientin (1), isoorientin (2), vitexin (3), isovitexin (4), isovitexin 7,2"-di-O-glucoside (5), isovitexin 7-O-galactoside-2"-O-glucoside (6), two different 6,8-di-C-hexosylapigenins (7, 8), and two different 6-C-hexosyl-8-C-pentosylapigenins (9, 10) have been either produced from flavonoid fractions from Adonis vernalis L. (1, 2) and Crataegus species (3, 4), or isolated from Stellaria media (L.) Vill. (5-10) to study their antioxidative properties. These were found only for two compounds: orientin (1) and isoorientin (2).