A noteworthy technological advancement in optical fiber transmission systems is the optical fiber communication system. It has a transmitter, medium, and detector modules within it. A laser is utilized as a carrier of light signals at the transmitter end. Achieving huge data in the form of Gb/s along with long-distance transmission is what is needed in long-haul communication. There are different techniques to meet this huge data rate of optical fiber communication systems, such as using HOA, a gain flattening filter, and fiber Bragg gratings (FBG). Quadrature Amplitude Modulation (QAM), Optical Amplifiers, and DWDM MUX at the transmitter and DWDM DEMUX receiver at the receiver module. This research work focuses on the design and analysis of C+L band gain flattening. The C-band, or conventional band, supports wavelengths from 1530nm to 1565nm. Whereas, the long band (L band) supports the wavelength window from 1565nm to 1625nm. In the digital modulation schemes, QAM is used for symbol generation due to its higher spectral efficiency, efficient bandwidth, and robustness to interference and noise compared to other digital modulation techniques.Performance metrics for the C band, L band, and C+L band have been explicitly studied and analyzed. With the system generic modal designed, the gain variation under varying input laser power has been recorded at -10 dBm and is approximately 21.6140207 % from 14.144527 dB to 17.201728 dB for the L band wavelength window. At 60 km OFC distance, we recorded the highest gain in the C band wavelength window. In percentile, the corresponding variation is roughly 18.79783463 % from 13.251122 dB user 1 to 15.742046 dB user 16.With varying values, the hybrid optical amplifier for 32 users, which includes the Raman optical amplifier,the gain varies 19.951204 dB to 25.310008 dB tends to vary the gain flatness 26.8595519 %.The best gain flatness, therefore, is found in hybrid optical amplifiers. Using the designed system, the BER versus distance, gain vs. EDFA length, OSNR versus distance, bit errors versus distance, and more parameters will be analyzed and demonstrated. Key Words: EDFA, GAIN , NOISE FIGURE, SOA, GFF, DWDM