US 12,298,650 B2
Method of measuring electro-optic characteristic of a traveling wave mach-zehnder modulator and device for same
Ming Yang Jung, Kaohsiung (TW); Lan-Chou Cho, Hsinchu (TW); and Stefan Rusu, Sunnyvale, CA (US)
Assigned to TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Hsinchu (TW)
Filed on Jun. 8, 2022, as Appl. No. 17/835,414.
Prior Publication US 2023/0400745 A1, Dec. 14, 2023
Int. Cl. G02F 1/225 (2006.01); G01B 9/02055 (2022.01); G02B 6/12 (2006.01); G02F 1/01 (2006.01); G02F 1/21 (2006.01)
CPC G02F 1/2255 (2013.01) [G01B 9/0207 (2013.01); G02B 6/12004 (2013.01); G02F 1/0121 (2013.01); G02F 1/212 (2021.01); G01B 2290/60 (2013.01); G02B 2006/12061 (2013.01); G02B 2006/12142 (2013.01); G02B 2006/1215 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of characterizing a traveling-wave Mach-Zehnder modulator (TWMZM), the method comprising:
providing a test TWMZM including a phase modulator with first and second optical waveguides and a radio frequency (RF) transmission line electrically coupled with the first and second optical waveguides, a first instance of an optical splitter optically coupled to input light to first ends of the first and second optical waveguides, and a first instance of an optical combiner optically coupled to combine light from second ends of the first and second optical waveguides;
providing a reference TWMZM including a vestigial phase modulator that is shorter than the phase modulator of the test TWMZM with vestigial first and second optical waveguides and a vestigial RF transmission line electrically coupled with the vestigial first and second optical waveguides, a second instance of the optical splitter optically coupled to input light to first ends of the vestigial first and second optical waveguides, and a second instance of the optical combiner optically coupled to combine light from second ends of the vestigial first and second optical waveguides;
acquiring an electrooptic measurement of a test structure including the test TWMZM and a first instance of electrical pads connected to drive the RF transmission line of the test TWMZM;
acquiring an electrooptic measurement of a reference structure including the reference TWMZM and a second instance of the electrical pads connected to drive the vestigial RF transmission line of the reference TWMZM; and
determining an electrooptic characteristic of the test TWMZM by operations including removing a contribution of the first instance of electrical pads to the electrooptic measurement of the test structure by subtracting the electrooptic measurement of the reference structure from the electrooptic measurement of the test structure.