	US 11,886,056 B2
	Electro-optical modulator using waveguides with overlapping ridges
Donald Adams, Rochester, NY (US); Prakash B. Gothoskar, Allentown, PA (US); Vipulkumar Patel, Breinigsville, PA (US); and Mark Webster, Bethlehem, PA (US)
Assigned to Cisco Technology, Inc., San Jose, CA (US)
Filed by Cisco Technology, Inc., San Jose, CA (US)
Filed on Nov. 24, 2021, as Appl. No. 17/456,468.
Application 16/789,317 is a division of application No. 15/615,290, filed on Jun. 6, 2017, granted, now 10,598,967, issued on Mar. 24, 2020.
Application 17/456,468 is a continuation of application No. 16/789,317, filed on Feb. 12, 2020, granted, now 11,226,505.
Application 15/615,290 is a continuation of application No. 14/248,081, filed on Apr. 8, 2014, granted, now 9,766,484, issued on Sep. 19, 2017.
Claims priority of provisional application 61/931,314, filed on Jan. 24, 2014.
Prior Publication US 2022/0082875 A1, Mar. 17, 2022
Int. Cl. G02F 1/025 (2006.01); G02F 1/01 (2006.01); G02B 6/132 (2006.01); G02B 6/136 (2006.01); G02F 1/225 (2006.01); G02F 1/015 (2006.01)

CPC G02F 1/025 (2013.01) [G02B 6/132 (2013.01); G02B 6/136 (2013.01); G02F 1/011 (2013.01); G02F 1/2257 (2013.01); G02F 1/0152 (2021.01)]

20 Claims

1. A device, comprising:

a first waveguide disposed on a substrate, the first waveguide comprising a ridge projecting in a first direction from the substrate and extending in a second direction of an optical path;

a dielectric layer having a lower surface disposed on an upper surface of the ridge; and

a second waveguide comprising a first, planar surface disposed on an upper surface of the dielectric layer opposite the lower surface of the dielectric layer contacting the ridge, wherein a width of the first, planar surface is greater than a width of the dielectric layer and the ridge, and wherein the first waveguide is doped a first conductivity type and the second waveguide is doped a second, different conductivity type; and

a silicon nitride layer disposed on at least three sides of the second waveguide.