We demonstrate a femtosecond Yb:fiber laser amplification system which delivers 97 W average output power at a repetition rate of 1.08 GHz using a rod-type photonic crystal fiber. The re-compressed output pulse is 233 fs. Numerical simulation was also conducted in agreement with our experimental results.
Spatiotemporal coupling is present when the electric fields of any pulsed beams fail to separate into a product of purely spatial and temporal factors, and it affects ultimately on the propagation of the light. Here we study the effect of spatiotemporal coupling on the Hanbury Brown and Twiss (HBT) effect for the first time, with the help of our recent developed method [Opt. Express28, 32077 (2020)10.1364/OE.405726], by assuming the Gaussian statistics of partially coherent spatiotemporal pulsed sources containing the intensity and correlation coupling effect between the spatial and temporal domain. The generalized results for the spatiotemporal coupling HBT effect are investigated and through a nontrivial two-dimensional case, we numerically illustrate the influence of the spatiotemporal coupling on the HBT effect. It observes that even a very tiny coupling effect will strongly change the HBT effect at longer distances. This work will be potentially useful for the study of the HBT effect (intensity-intensity correlations) with dynamic sources having spatiotemporal coupling in both optics and other branches of physics.
Enduring the rapidly growing demand for high data rates is the main challenge for the current network providers. Super passive optical network (Super-PON), a prominent next generation Ethernet PON (NG-EPON) candidate, can suffice this exponentially increasing data rate requirements. However, to appease such requirements, it employs many transceivers and increases the power-consumption of the network. In this work, we focus on reducing the carbon footprint of Super-PON and propose power-efficient dynamic bandwidth and wavelength allocation (DBWA) algorithms, namely best fit bin-packing sleep mode aware (BF-SMA) and updated BF-SMA (UBF-SMA). The proposed algorithms use SMA for bandwidth scheduling and different bin-packing techniques for wavelength allocation. In bin-packing, the number of available wavelengths and their efficient allocation is based on the network load. For restricting the number of available wavelengths, we can switch off the non-essential transceivers at the OLT, which also helps in maximizing the wavelength utilization and increasing the power efficiency. The simulation results show that in comparison to the state-of-the-art DBWA algorithms, the proposed algorithms improve the power efficiency and reduce the average delay of a Super-PON system. Furthermore, we use Jain’s fairness index to validate the fairness of the proposed DBWA algorithms.
Collimated ultraviolet (UV) light is generated via four-wave mixing (FWM) in cesium vapor by continuously tuning the wavelength of the pump laser. Terahertz (THz) Stokes light is generated by the stimulated Raman scattering (SRS) effect in the FWM process, and its frequency is adjustable. When exciting the cesium atom to a virtual level using different combinations of pump lasers (P1 and P2), the strength distribution of UV light is asymmetric, which can be explained through a phase-matching mechanism. Furthermore, the SRS effect and phase matching influence the FWM.
