1：Experimental Design and Method Selection:

The study uses a system model with optical cross-connect (OXC) and erbium doped fiber amplifier (EDFA) for 10/40/100 Gb/s transmission line rates. Various modulation techniques (OOK, NRZ-OOK, RZ-OOK, DPSK, DQPSK, PM-QPSK, OQPSK) are analyzed for BER performance under different spontaneous emission factors (nsp = 1, 1.5, 2). Theoretical models and equations for BER and other parameters are employed.

2：5, 2). Theoretical models and equations for BER and other parameters are employed. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Simulation-based study using MATLAB; no specific sample or dataset mentioned.

3：List of Experimental Equipment and Materials:

Optical cross-connect (OXC), erbium doped fiber amplifier (EDFA), parameters such as number of wavelengths (40), line rates (10, 40, 100 Gb/s), optical bandwidth (50 GHz), input power (1 mW), ASE factor (1, 1.5, 2), amplifier gain (10 dB), channel spacing (50 GHz), BER threshold (10^-12), dispersion parameter (17 ps/nm/km), non-linear Kerr coefficient (2.2 dB (W m)^-2), fiber attenuation (0.2 dB/km), span length (60 km), Planck's constant (6.63e-34 J/Hz).

4：5, 2), amplifier gain (10 dB), channel spacing (50 GHz), BER threshold (10^-12), dispersion parameter (17 ps/nm/km), non-linear Kerr coefficient (2 dB (W m)^-2), fiber attenuation (2 dB/km), span length (60 km), Planck's constant (63e-34 J/Hz). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Simulations are carried out in MATLAB to evaluate BER for different modulation techniques under varying nsp values. The process involves setting up the system model, applying modulation schemes, and calculating BER using derived equations.

5：Data Analysis Methods:

BER is calculated using specific equations for each modulation technique. Results are plotted and compared for different nsp values to assess performance.