Patent ID: 8649690

Claim:
A method for maintaining a consistent local-oscillator-power-to-primary-signal-power ratio, the method comprising: receiving voltages for a plurality of optical signal components from a combined optical signal (SIG) and local oscillator (LO) signal; determining individual factors for the plurality of optical signal components; averaging the individual factors that results in an averaged output; determining whether the averaged output is less than a minimum reference value for a variable optical attenuator; determining whether the averaged output is greater than a maximum reference value for the variable optical attenuator; changing a value associated with the averaged output to the minimum reference value, due to determining that the averaged output is less than the minimum reference value; changing a value associated with the averaged output to the maximum reference value, due to determining that the averaged output is greater than the maximum reference value; and generating a new value associated with the averaged output to be transmitted to the variable optical attenuator.