High-speed transmission system for optical channels

#The present invention relates generally to apparatus and methods for high speed data transmission over optical channels, and, in particular embodiments, to transmission of data using pulse amplitude modulation, trellis coding, and equalization techniques.

#The demand for higher capacity data transmission systems continues to increase. To satisfy the ever increasing demand for more data transmission capacity higher baud rate systems such as optical channels have been used. At high baud rates some optical fibers may exhibit phenomena such as multimode transmission characteristics and intersymbol interference, which can limit the signaling rate available on that fiber. Therefore, there is a need within the art for methods and apparatus that are capable of higher baud rates, and for those which can compensate for the problems encountered with high speed data transmission.

#In one aspect of the invention, an apparatus for transmitting data on a fiber optic channel is disclosed. The apparatus comprises a trellis encoder that accepts data to be transmitted, applies a convolutional coding to a portion of the data, and produces a trellis coding of the data to be transmitted. A subset mapper accepts the trellis coding and produces a plurality of pulse amplitude modulated (PAM) symbols from the trellis coding. A Tomlinson precoder accepts the PAM symbols and applies a Tomlinson precoding the PAM symbols. A converter converts the PAM symbols into a form for coupling into a fiber channel.

#These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

#FIG. 1 is a block diagram illustrating components of an optical data communication system.

#FIG. 2 is a block diagram of a optical communication system according to an embodiment of the invention.

#The demand for higher data carrying capacity transmissions systems continues to increase. Accordingly, embodiments of the present invention relate to methods and apparatus for increasing the rate of data transmission in optical transmission systems.

#FIG. 1 is a block diagram illustrating a prior art optical data communication system.

#In FIG. 1 a data source 101 provides data to be transmitted over fiber optic channel 109. Data source 101 may be, for example, the Internet, a cable television head end, a corporate network or a variety of other data sources.