Patent ID: 7573923

Claim:
A laser drive circuit comprising: a laser including a drive current input configured to receive a drive current and an optical output configured to provide a modulated optical signal in response to the drive current, the laser having a threshold current such that low limit clipping occurs when the drive current to the laser falls below the threshold current; and a current clamp including an input configured to receive at least a RF signal and an output configured to provide a clamped current to the drive current input of the laser, the RF signal including negative peaks produced by a relatively large swing in drive current in a negative direction and including corresponding positive peaks produced by a corresponding relatively large swing in drive current in a positive direction, wherein the low limit clipping occurs in the laser when the negative peaks of the RF signal fall below the threshold current of the laser, the current clamp being configured to clamp the current of the RF signal to a high limit current such that the clamped current provided to the drive current input of the laser provides high limit clipping of the positive peaks corresponding to the negative peaks that cause the low limit clipping to occur in the laser, wherein the modulated optical signal includes high limit clipping substantially symmetrical to the low limit clipping that occurs in the laser.