Jean-Marc Pierre Delavaux

Spontaneous and stimulated Brillouin scattering gain spectra in optical fibers

We study the Brillouin scattering behavior in several single-mode fibers with different waveguide characteristics in terms of their longitudinal mode structures in the gain spectrum, linewidth narrowing, and stimulated Brillouin scattering (SBS) threshold levels. Evolution from spontaneous to SBS is investigated by monitoring the Brillouin line-shape and the behavior of the longitudinal acoustooptic resonance modes that exist in the core. We compare our results with the current theory of Brillouin scattering generated from noise in the undepleted pump approximation. We also present experimentally Brillouin gain spectra in the highly depleted pump regime, where there is no analytical solution, by showing the evolution of the gain spectrum as a function of the injected laser intensity.

Eliminating SRS channel depletion in massive WDM systems via optical filtering techniques

We demonstrate that the channel depletion due to stimulated Raman scattering in massive wavelength-division-multiplexed (WDM) systems can be eliminated using high-frequency pass filters. These filters, when inserted appropriately into the transmission link, can effectively suppress the SRS power flow from the WDM channels to lower frequency noise. Numerical simulations carried out on WDM systems indicate that the channel depletion penalties can be kept below 0.25 dB even for a total channel power of 2 W.

Duty cycle ratio dependence on the performance of a Q-switched laser with an Er 3+ –Yb 3+ codoped glass waveguide

We examine the performance of a hybrid Q-switched LiNbO(3) and Er(3+)-Yb(3+) doped glass waveguide laser as a modulation function of the duty cycle ratio. As the duty cycle ratio decreases, the laser operates at higher peak power and pulse width. At low duty cycle ratio (<1%), we observe variations in the Q-switched pulse shape; while the laser produces 59-W and 200-ns pulses to a 1-kHz repetition rate for a 50% duty cycle, it yields 27-W and 100-ns pulses to a 10-kHz repetition rate for a 0.01% duty cycle.