US 12,476,711 B2
In-phase (I) / quadrature (Q) correlation dither for modulator quadrature control
Shahab Oveis Gharan, Ottawa (CA); Yves Beaulieu, Nepean (CA); Douglas McGhan, Ottawa (CA); and Kim Byron Roberts, Ottawa (CA)
Assigned to CIENA CORPORATION, Hanover, MD (US)
Filed by CIENA CORPORATION, Hanover, MD (US)
Filed on Jun. 2, 2023, as Appl. No. 18/328,027.
Prior Publication US 2024/0405880 A1, Dec. 5, 2024
Int. Cl. H04B 10/516 (2013.01)
CPC H04B 10/516 (2013.01) 21 Claims
OG exemplary drawing
 
1. A device, comprising:
a modulator configured to output an optical signal; and
a control system configured to cause the modulator to create two orthogonal output dimensions, in-phase (I) and quadrature (Q), based on two inputs xI and xQ derived from a digital input signal, by:
performing controlled introduction of a correlation between the two inputs xI and xQ for the modulator, wherein the controlled introduction corresponds to use of a controlled correlated term from the input xI to the input xQ, or from the input xQ to the input xI, that is filtered out via a digital filter, and wherein the controlled correlated term enables detection of any frequency-dependent non-orthogonality within dimension I radio frequency (RF) drive signals and within dimension Q RF drive signals or within I and Q arms of the modulator; and
detecting a resulting output power of the modulator to facilitate operation of the modulator.