Widely tunable wavelength exchange in anomalous-dispersion regime

We demonstrate the 10-Gb/s wavelength exchange with two pumps in the anomalous-dispersion region. Results show that performance degradation caused by Raman gain is avoided so that a nearly complete exchange can be achieved. In this letter, we also investigate the tunability of wavelength exchange for the first time to the best of our knowledge. Complete wavelength exchange is achieved with tuning range >15 nm. A bit-error rate of <10-9 is maintained with power penalties of ∼2 dB using 27-1 pseudorandom bit sequence (PRBS). © 2007 IEEE.published_or_final_versio

A comprehensive study on the dynamic range of wavelength exchange and its impact on exchanged signal performance

Effects of the incomplete signal exchange on the dynamic range performance of type II wavelength exchange (WE II, i.e. both pumps are in anomalous dispersion region) are investigated analytically and experimentally. The dynamic range here is defined as the tolerable operational range of the signal power to maintain a nearly complete WE performance. We studied the case of equal signal powers (balanced signal powers) as well as the case of unequal signal powers (imbalanced signal powers). It is demonstrated that the beating between exchanged signal and residual one and the extinction ratio degradation due to the existence of residual power at original channel is the major source of the signal quality degradation after WE II. The experimental results demonstrated dynamic range ∼17 dB with bit-error rate (BER) < 10-9 could be maintained with power penalty of <2 dB in the case of balanced signal powers. In the case of imbalanced signal powers, the dynamic range was <8 dB with the power penalty incurred of ∼2 dB in the worst case. © 2009 IEEE.published_or_final_versio

Dynamic range of wavelength exchange in highly nonlinear dispersion-shifted fiber

We investigate the signal dynamic range of wavelength exchange using 10Gb/s 231-1 PRBS. Data exchanging between two wavelengths is achieved with signal dynamic range ∼20dB. Bit-error-rate of <10-9 is maintained with power penalties of <2dB. © 2008 Optical Society of America.published_or_final_versio

Performance of Wavelength Exchange in Anomalous-dispersion Region

link_to_OA_fulltex

Gain optimization of Raman-mediated fiber optical parametric amplifiers

Fiber optical parametric amplifiers (OPAs) and Raman amplifiers (RAs) are both based on the third-order nonlinear susceptibility of glass fibers. Recently, there have been some efforts to combine these two nonlinear phenomena in order to extend the amplification and wavelength conversion windows to the S-band, or to lower the required parametric pump power in order to achieve the same signal gain. We propose a new technique utilizing these two amplication principles in a single piece of highly-nonlinear dispersion-shifted fiber (HNL-DSF). We call this Raman-mediated fiber OPA (RM-OPA), which is different from the previous Raman-assisted OPA (RA-OPA) work. The previously investigated RA-OPA required an extra Raman pump with power around 1 W, on top of the erbium-doped fiber amplifier (EDFA) required to amplify the OPA pump. Therefore, Raman amplification was simply employed as a power booster for the OPA pump, i.e. RA "assists" OPA. On the other hand, our new approach does not require an extra EDFA as pre-amplifier, and the single piece of HNL-DSF provides both RA and OPA effects. In other words, there is essentially no parametric amplification without the presence of the Raman pump. While combining RA and OPA have been investigated both analytically and experimentally before, it involved only introducing some extra Raman terms in the nonlinear Schrödinger equations (NLSE) additively, which is sufficient for the case when one pump is used to amplify the signal (and idler) through both RA and OPA. However, the situation is significantly different here, where the parametric pump is amplified by the RA, while the OPA gain varies along the gain medium as the parametric pump power itself is a function of the distance along the HNL-DSF. In this paper, we will present an approximate analytical model for this RM-OPA, in a co-propagating configuration. Through certain simplifying assumptions, we produce closed-form equations allowing intuitive insights into the RM-OPA operation, given the coupling amongst the parametric pump, Raman pump, signal and idler. These equations provide a framework for optimizing such kind of fiber amplifiers. Important RM-OPA design guidelines are also discussed.link_to_subscribed_fulltex

High Extinction Ratio of Switched Packets by Two-Stage Four Wave Mixing in Highy Nonlinear Dispersion-Shifted Fiber

link_to_OA_fulltex

All-optical packet switching by pulsed-pump wavelength exchange in a highly nonlinear dispersion-shifted fiber

We demonstrate experimentally for the first time successful switching of packets based on wavelength exchange with two pulsed pumps located at the anomalous-dispersion region. Simultaneous packet switching between different wavelengths at same timeslot is achieved. © 2007 Optical Society of America.link_to_subscribed_fulltex

Wavelength exchange using two pumps in anomalous Regime

We investigate the wavelength exchange with two pumps at the anomalous-dispersion region. Results show that performance degradation caused by Raman effect is avoided in this configuration such that symmetric power transfer and nearly-complete exchange can be achieved.link_to_subscribed_fulltex

Wavelength exchange with enhanced extinction ratio in highly nonlinear dispersion-shifted fiber

We demonstrate a simple approach to enhance the extinction ratio of wavelength exchange with a polarization-diversity technique. Over 25 dB of extinction ratio is attained with 6 dB improvement over that of the conventional configuration. © 2007 Optical Society of America.link_to_subscribed_fulltex

“Remind-to-Move” for promoting upper extremity recovery using wearable devices in subacute stroke : a multi-center randomized controlled study

202303 bckwAccepted ManuscriptRGCPublishe