Optical receiver front-end for multilevel signalling

A front-end optical receiver in 0.6 m BiCMOS technology is introduced to maintain equally spaced levels and constant output signal swing for multilevel signals at different input optical powers. The symbol error rate measurements for 4-PAM signals show a better sensitivity than with a conventional optical receiver. It is believed that this is the first time that complete performance characteristics for an optical receiver front-end designed especially for multilevel data transmission have been reported.