A study on gain modulation dynamics of 80 nm-band high-power Raman amplifier

Abstract

We have studied the gain modulation characteristics of 80nm-band high-power backward-pumped Raman amplifier. We found that flat gain madulation r o p o k *as obtained mer the-enure rignil bandwidth b) ~ntenrq-modulating thc longestuarelenmh Dum0 livht <JUI;C at a frcaurnc! .. .....Recent demonstrations ha\< rhoun that the use of dirtnbacd Raman amplification (DR4) 15 the kc) to achme seamless ultrawide sign31 bandwidth [I-31. In gmcral, u,hcn ne use many such optical ampltficr, in ciscadc to configure a multt.repealer s)stcm, such as transoceanic sptems, remote ,upenisor) of each repeater IC one of the cmcial technological IWCI for practical applicitions In transoceanic s\slems usmi EDFA rcocatcrs one

Flat-Gain Fiber Raman Amplifiers Using Equally Spaced Pumps

“…Therefore, in the case of a fixed central wavelength, the pump wavelengths are chosen and fixed, while in the case of the optimized central wavelength, the wavelength spacing is fixed, but the pump wavelengths are strictly determined by the central wavelength, which is optimized by the genetic algorithm. Although the wavelengths could have any value, we chose them to be evenly spaced for consistency with experimental work to date [4], [5]. Choosing the pumps to be evenly spaced simplifies the design and aids initial coupling into the systems in the experiments [11].…”

“…Hence, it is often used in practice. In fact, a recent experiment has demonstrated 80 nm of flat gain using four equally spaced Raman pumps [5]. Another potential drawback of the method outlined in [2] and [3] is that the optimal wavelengths chosen by the algorithm may not be commercially available.…”

Gain modulation dynamics of a Raman amplified WDM system using time-division multiplexed pumps

“…The shorter wavelength pumps transfer energy to the longer wavelength pumps due to Raman interactions thus providing larger gains to the longer wavelength signals. The CW pump power values are now adjusted to get a flatter [3] gain (pumps-adjusted). Next, TDM pumping is employed and pump powers determined to achieve similar gain as CW multiple pumping (TDM).…”

“…The bandwidth of the transfer process depends on the pumping scheme and has been studied for counter and co-pumped Raman amplifiers employing a single signal and pump [1,2]. The gain modulation dynamics is more complex for Wavelength Division Multiplexed (WDM) systems and has been shown experimentally [3] to be dependent on the choice of pump wavelength chosen for the modulation of supervisory signals, Raman on-off gain and the bandwidth of the supervisory signals.…”