US 12,081,271 B2
Digital tone-based apparatus and method for measuring the frequency response of coherent optical transmitters
Amir Rashidinejad, Ottawa (CA); and Wenbo Gao, Allentown, PA (US)
Assigned to Infinera Corporation, San Jose, CA (US)
Filed by Infinera Corporation, San Jose, CA (US)
Filed on Dec. 30, 2022, as Appl. No. 18/091,870.
Application 18/091,870 is a division of application No. 17/375,575, filed on Jul. 14, 2021.
Claims priority of provisional application 63/051,815, filed on Jul. 14, 2020.
Prior Publication US 2023/0146826 A1, May 11, 2023
Int. Cl. H04B 10/548 (2013.01); H04B 10/50 (2013.01); H04B 10/58 (2013.01)
CPC H04B 10/548 (2013.01) [H04B 10/503 (2013.01); H04B 10/58 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A method, comprising:
generating electrical signal indicative of an amplitude modulated (AM) tone;
supplying the electrical signals to digital-to-analog circuitry, which outputs a plurality of analog signals;
providing the analog signals to driver circuitry, which outputs a plurality of drive signals;
supplying the drive signals to a modulator including a Mach-Zehnder modulator;
outputting light from a laser;
modulating the light output from the laser with the modulator to provide a modulated optical signal, the modulated optical signal including a plurality of optical subcarriers, such that each of the plurality of optical subcarriers has a particular frequency;
collectively applying the AM tone to each of the plurality of optical subcarriers, the AM tone having a fixed amplitude modulated (AM) frequency at a first known carrier frequency component at a first period of time and a second known carrier frequency component at a second period of time;
measuring a power of a modulated optical signal generated based at least in part on the AM tone at the first period of time and at the second period of time; and
normalizing measured power to obtain an amplitude response.