Patent ID: 9172471
Filing Date: 2015-10-27
Classification: H04B

Abstract:
1. A system for suppressing even-order distortion in a photonic link, comprising: a laser light source for generating a laser light output; a Mach-Zehnder modulator (MZM) having a first input coupled to the laser light output, a second input for receiving an RF input signal, a third input for applying a DC bias voltage to the MZM, and an optical signal output, and a dc-voltage-biased photodiode having an input coupled to the optical signal output and a modulated RF signal output, and where the MZM DC bias voltage is set at a value away from a quadrature point such that an even-order distortion amplitude generated by the MZM due to an MZM transfer function combined with a photodiode response given by where φ dc =πV dc /V π,dc −a 2 is second order Taylor series coefficient of the photodiode, V dc is the DC voltage applied to the input of the MZM, V π,dc is the DC half-wave voltage of the MZM, and I dc,q is the DC photocurrent at the quadrature point is equal to an even-order distortion amplitude from the photodiode and 180 degrees out of phase so as to cancel the photodiode even-order distortion.