Patent ID: 8165474

Claim:
A modulated optical system with anti-clipping, the system comprising: a laser including a RF input configured to receive a multichannel RF signal, a bias input configured to receive a bias current, and an optical output configured to provide a modulated optical signal in response to the multichannel RF signal and the bias current, the multichannel RF signal including a superposition of multiple carriers; envelope follower circuitry configured to receive the multichannel RF signal, to detect an envelope of the multichannel RF signal and to generate an anti-clipping signal that follows at least a portion of the envelope of the multichannel RF signal, wherein the envelope follower circuitry is configured to clamp the anti-clipping signal at an anti-clipping limit when the power of the multichannel RF signal falls below a power level, wherein the envelope follower circuitry comprises a precision rectifier circuit including at least one input and output, the precision rectifier circuit being configured to receive the multichannel RF signal, to detect the envelope of the multichannel RF signal and to produce the anti-clipping signal on the output, wherein the precision rectifier circuit is further configured to receive an anti-clipping limit signal on the input with the multichannel RF signal, wherein the anti-clipping limit signal is indicative of the anti-clipping limit, and wherein the anti-clipping signal produced on the output of the precision rectifier is prevented from falling below the anti-clipping limit; and bias control circuitry coupled to the envelope follower circuitry and to the bias input of the laser, the bias control circuitry being configured to vary the bias current provided to the laser in response to the anti-clipping signal such that at least one negative voltage spike in the RF signal is prevented from causing clipping in the laser.