DPPM FSO communication systems impaired by turbulence, pointing error and ASE noise

Performance analyses, using a modified Chernoff bound on the bit error rate, are given for an optically preamplified digital pulse position modulation (DPPM) free-space optical (FSO) communication system impaired by pointing error and atmospheric turbulence combined, in addition to the amplified spontaneous emission noise arising from the optical amplification. An improvement of about 7-9 dB (depending on the turbulence level) can be potentially achieved using the DPPM scheme over an equivalent on off keyed nonreturn-to-zero based FSO system.