Circuit design of a loss of signal for four-channel parallel 5Gbps/ch optical receiver

We present a circuit design of a loss of signal (LOS) for four-channel parallel optical receivers which have promising applications in the future high performance computing systems. This LOS includes a sensitive amplifier, a peak detect circuit and a comparator. The LOS is placed between a trans-impedance amplifier and a limiting amplifier, so as to achieve the advantages of low power consumption compared to the structure where LOS follows the limiting amplifier. Cadence Virtuoso simulations demonstrate that the whole optical receiver circuit works well when the input current amplitude of optical receiver is between 40µApp and 200µApp. When the input current amplitude is below 20µApp, the limiting amplifier and the buffer stop working because the LOS turning them down. The simulation results show that the LOS circuit with DC consumption of 15.14mW could work in 5Gbps high performance computing data transmission systems, achieving 62.6% power saving when the input signal of optical receiver is below 20µApp.