Gain flattened and C/L band amplified spontaneous emission noise re-injected L-band EDFA

Explosive increase in internet services put peer pressure on conventional band grid (1530–1570 nm) and therefore L-band wide wavelength grid is required to cater the ever-increasing demands. In this work, accentuation is given to enhance the gain flattening of ultradense (25 GHz) L-band WDM system using single stage EDFA amplifier when ultralow power is launched from 16 and 32 channels. High gain and gain flattening is achieved by incorporating three fiber Bragg gratings (FBGs) for amplified spontaneous noise reinjection. Maximum Amplified spontaneous emission (ASE) is emerged at 1565 nm for the 1575.69–1579 nm input wavelengths (16 channels) and 1572.58–1579 nm (32 channels) at −55 dBm ultra low carrier powers. To optimize different parameters of L-band EDFA, different physical parameters such as core radius, EDF link lengths, and launched powers are varied, and results are analyzed in terms of lateness. Maximum gain is found out to be 34.12 dB at optimal physical parameters of the EDF with gain flatness of ±0.45 dB in case of 16 channels and ±1.41 in case of 32 channels.

EDFA gain flattening optimization with long period fiber gratings in WDM system

This paper highlights a proposed optimized gain flatness technique for nonuniform gain spectrum of the erbium-doped fiber amplifier (EDFA) by introduction of long period fiber gratings (LPFG). In this analysis, EDFA gain spectrum has been evaluated between 1525 and 1600 nm with −20 dBm input signal power. Attenuation peaks of LPFG are optimized with a grating period of 240 µm and grating length of 30000 µm in the wavelength range of 1.1–1.8 μm, to compensate the peak gain of EDFA. Results have shown that EDFA peak gain of 35.94 dB is achieved at 1532.89 nm wavelength. This 35.94 dB peak gain is flattened up to 2.65 dB using long period fiber gratings. Also, less than ±0.3 dB gain flatness is achieved between 1528 and 1560 nm wavelength. The proposed less complex technique can be used to modify the grating parameters during fabrication in order to produce the loss peak at desired wavelength, which is efficient to flatten EDFA gain peak.