US 12,283,986 B2
Optical wavemeter
Marcel Zeiler, Boeblingen (DE); and Bernd Nebendahl, Ditzingen (DE)
Assigned to KEYSIGHT TECHNOLOGIES, INC., Santa Rosa, CA (US)
Filed by Keysight Technologies, Inc., Santa Rosa, CA (US)
Filed on Mar. 28, 2023, as Appl. No. 18/127,184.
Application 18/127,184 is a continuation in part of application No. 17/874,513, filed on Jul. 27, 2022, granted, now 12,174,509.
Application 17/874,513 is a continuation in part of application No. 16/943,056, filed on Jul. 30, 2020, granted, now 11,536,610, issued on Dec. 27, 2022.
Claims priority of provisional application 62/928,704, filed on Oct. 31, 2019.
Prior Publication US 2023/0239046 A1, Jul. 27, 2023
Int. Cl. G02B 6/293 (2006.01); H04B 10/079 (2013.01); H04B 10/61 (2013.01)
CPC H04B 10/07957 (2013.01) [G02B 6/2935 (2013.01); G02B 6/29352 (2013.01); H04B 10/07955 (2013.01); H04B 10/614 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus for determining an wavelength and a power of an input optical signal, the apparatus comprising:
a first optical splitter adapted split power of the input optical signal into a first output optical signal and a second output optical signal;
a second optical splitter connected to a first arm of the first optical splitter, and adapted to split the first output optical signal into a third output optical signal and a fourth optical signal;
a third optical splitter connected to a second arm of the first optical splitter, and adapted to split the second output optical signal into a fifth output optical signal and a sixth optical signal;
a first Mach-Zehnder Interferometer (MZI) having a first free spectral range (FSR);
a second Mach-Zehnder Interferometer (MZI) having a second FSR, wherein the first MZI has a first optical path length (OPL) difference, and the second MZI has a second optical path length (OPL) difference, which is greater than the first OPL difference;
a processor; and
a memory which stores instructions, which when executed by the processor, cause the processor to: recover a first phase for the first MZI; recover a second phase for the second MZI; subtract the first phase from the second phase to provide a phase difference; determine an unwrapped phase difference as a function of wavelength; determine a coarse wavelength; determine a first wavelength for the first MZI and a second wavelength from the second MZI; and average the first and second wavelengths to determine the wavelength of the input optical signal.