A wavelength division multiplexing (WDM) access network using high-speed free-space optical (FSO) communication for the distribution link is proposed. This Paper investigates terrestrial atmospheric of WDM-FSO communication systems operating under the influence of turbulence-induced scintillation, beam spreading, optical interchannel crosstalk, amplified spontaneous emission noise and pointing errors.On-off keying-non–return-to-zero and digital pulse position modulation are the modulation schemes used for the calculations.