Patent ID: 11870407
Assignee: NEOPHOTONICS CORPORATION
Field: Optics (Instruments)
Classification: CPC H  G | IPC G  H

Claim 0:
1. A method comprising:
transmitting a dither signal and a data signal to radio frequency (RF) electrodes of a Mach-Zehnder Modulation (MZM) phase modulator to enable calculation of a voltage drift, the MZM phase modulator comprising:
an optical input waveguide,
an optical output waveguide, and
MZM arms extending therebetween,
wherein each of the MZM arms includes an RF electrode, of the RF electrodes, and a resistive heater;

receiving, from a variable gain amplifier (VGA), via an analog-to-digital converter (ADC), and based on calculation of the voltage drift, a signal;
determining, based on the signal, a voltage bias by integrating a time derivative voltage bias as a function of time,
wherein the function is proportional to a sum of a product of unsealed dither values and a mean bias intensity, and
wherein the sum runs over points of a buffer based on a frequency of the ADC and a frequency of the dither signal; and

applying the voltage bias to the resistive heater to produce an optical phase shift that corrects the voltage drift.