Patent ID: 7613399

Claim:
An optical transmission system in which data is multilevel-coded and the multilevel-coded data is transmitted, comprising: an optical transmitter including: a driving section for converting the data to a first multilevel code and a second multilevel code, a difference between the first multilevel code and the second multilevel code being previously assigned to the data; a first light emitting section for outputting a first multilevel optical signal having intensity corresponding to the first multilevel code; and a second light emitting section for outputting a second multilevel optical signal having intensity corresponding to the second multilevel code; and an optical receiver including: a first photo-detecting section for receiving the first multilevel optical signal and converting the first multilevel optical signal to a first electrical signal; a second photo-detecting section for receiving the second multilevel optical signal and converting the second multilevel optical signal to a second electrical signal; and a decoding section for decoding the data which is previously assigned to a difference between the first electrical signal and the second electrical signal.