Methods, circuits and optical cable assemblies for optical transmission of high-speed data and low-speed data

A circuit for providing optical communication comprising:

• a laser;
• and
• a laser driver circuit that digitally modulates an output of the laser to transmit high-speed optical data at a first bit rate;
• and
• an amplitude modulation circuit that modulates an amplitude of the laser to transmit low- speed optical data at a second bit rate simultaneously with the high-speed optical data, wherein the first bit rate is higher than the second bit rate, wherein
• the laser driver circuit and the amplitude modulation circuit applies a laser driver current ILD to the laser, and
• the laser driver circuit is configured to modulate the laser driver current ILD by adding and removing a drive current ID to and from a bias current IB to produce the high-speed optical data, and by adding and removing a delta current IΔto and from the drive current ID to produce the low-speed optical data.

An active optical cable assembly comprising:

• an optical fiber having a first end;
• a first electrical connector at the first end of the optical fiber;
• a laser disposed within the first electrical connector;
• a laser driver circuit within the first electrical connector that digitally modulates an output of the laser to transmit high-speed optical data at a first bit rate over the optical fiber in accordance with a high-speed data stream received at the first electrical connector;
• and
• an amplitude modulation circuit within the first electrical connector that modulates an amplitude of the laser to transmit low-speed optical data at a second bit rate simultaneously with the high-speed optical data over the optical fiber in accordance with a low-speed data stream received at the first electrical connector, wherein the first bit rate is higher than the second bit rate,
• wherein:
• the laser driver circuit controls the laser such that the high-speed optical data provided by the output of the laser is defined by a high optical power value PH that is above a threshold and a low optical power value PL that is below the threshold;
• and
• the amplitude modulation circuit modulates the amplitude of the output of the laser at the second bit rate such that:
• the high optical power value PH is either a first high optical power value PH1 or a second high optical power value PH2 that is greater than the first high optical power value PH1;
• and
• the low optical power value PL is either a first low optical power value PL1 or a second low optical power value PL2 that is less than the first low optical power value PL1.