Increased transmission capacity for a fiber-optic link

An optical communication system, comprising:

• an optical fiber;
• an optical transmitter, coupled to the optical fiber, the optical transmitter adapted to encode a composite optical signal based at least two, independent input signals;
• and
• an optical receiver, coupled to the optical fiber, the optical receiver adapted to decode the composite optical signal to reproduce the at least two, independent input signals as output signals.

An optical transmitter, including:

• a first input adapted to receive serial, digital data from a first source,
• at least one additional input adapted to receive serial, digital data from at least one additional source,
• an encoder circuit, coupled to the first and the at least one additional inputs, that produces an output signal with a selected level based on the serial, digital data from the first and the at least one additional sources, and
• an optical modulator, coupled to the encoder circuit, that produces a pulse amplitude modulated optical signal based on the levels of the signal from the encoder circuit and that provides the pulse amplitude modulated optical signal to an optical output for transmission.

An optical transmitter, including:

• a first input adapted to receive serial, digital data from a first source,
• at least one additional input adapted to receive serial, digital data from at least one additional source,
• an encoder circuit, coupled to the first and the at least one additional inputs, that encodes the serial, digital data from the first and the at least one additional sources into an electrical signal, and
• an optical modulator, coupled to the encoder circuit, that produces a pulse amplitude modulated optical signal based on the electrical signal from the encoder circuit and that provides the pulse amplitude modulated optical signal to an optical output for transmission.

An optical receiver, comprising:

• an optical input, adapted to be coupled to an optical fiber;
• an optical detector, coupled to the optical input, that receives a pulse amplitude modulated optical signal and produces an electrical signal with selected levels based on the pulse amplitude modulated signal;
• a decoder circuit, coupled to the optical detector, that produces a first and at least one additional serial, digital data stream based on the electrical signal from the optical detector,
• a first output and at least one additional output, coupled to the decoder circuit, the first and the at least one additional output provide the first and the at least one additional digital, serial data stream, respectively.

A method for encoding serial, digital data, the method comprising:

• receiving a first serial, digital data stream;
• receiving at least one additional serial, digital data stream;
• producing an encoded signal with levels based on the first and the at least one additional serial, digital data streams;
• producing a pulse amplitude modulated optical signal based on the levels of the encoded signal;
• transmitting the pulse amplitude modulated optical signal.

A method for transmitting a plurality of serial, digital data streams over an optical fiber link, the method comprising:

• receiving the plurality of serial, digital data streams;
• producing a pulse amplitude modulated optical signal based on the plurality of serial, digital data streams;
• and
• transmitting the pulse amplitude modulated optical signal.

A method for decoding a plurality of serial, digital data streams from an optical signal, the method comprising:

• receiving the optical signal, wherein the optical signal is a pulse amplitude modulated signal;
• converting the optical signal to an electrical signal;
• comparing the electrical signal with a plurality of levels;
• and
• generating the plurality of serial, digital data streams based on the comparison with the plurality of levels.

An optical transmitter, including:

• a first input adapted to receive serial, digital data from a first source,
• at least one additional input adapted to receive serial, digital data from at least one additional source,
• an encoder circuit, coupled to the first and the at least one additional inputs, that produces an output signal with a selected level based on the serial, digital data from the first and the at least one additional sources, and
• an optical modulator, coupled to the encoder circuit, that produces a composite optical signal based on the levels of the signal from the encoder circuit and that provides the composite optical signal to an optical output for transmission.