Operational stability of a spectrally encoded optical CDMA system using inexpensive transmitters without spectral control

We show that an 8 x 155.52 Mb/s optical code-division multiple-access system applying periodic spectral encoding can be operated with poor quality optical filters and only loosely specified optical sources while still achieving bit-error rates (BER) = 10(-10) for each transmitter in asynchronous operation, It is experimentally found that BER < 10(-9) is maintained, if the optical receiver filter periodicity is changed by up to +/-0.27%. From this finding we deduce that the optical transmitter filters do not need to be actively temperature controlled within the range -40 degrees C to +85 degrees C. This robustness is qualitatively understood from a simple crosstalk model depicted in the letter.