US 12,386,211 B2
Silicon optical phase shifter with a series of P—N junctions
Jianfeng Ding, New York, NY (US)
Assigned to Nokia Solutions and Networks Oy, Espoo (FI)
Filed by Nokia Solutions and Networks Oy, Espoo (FI)
Filed on Oct. 20, 2022, as Appl. No. 17/970,020.
Prior Publication US 2024/0134215 A1, Apr. 25, 2024
Prior Publication US 2024/0231132 A9, Jul. 11, 2024
Int. Cl. G02F 1/025 (2006.01); G02F 1/015 (2006.01); G02F 1/21 (2006.01); G02F 1/225 (2006.01)
CPC G02F 1/025 (2013.01) [G02F 1/0152 (2021.01); G02F 1/212 (2021.01); G02F 1/2257 (2013.01); G02F 2203/50 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An apparatus, comprising:
an optical phase shifter comprising:
a planar optical waveguide having a silicon optical core and a geometry of a rib waveguide, wherein dimensions of the silicon optical core as the rib waveguide include a rib width and a core thickness; and
a pair of biasing electrodes located along opposite sides of a segment of the silicon optical core;
wherein the segment of the silicon optical core comprises a series of p-n junctions, the series extending in a direction transverse to an optical propagation direction of an optical signal and across the rib width of the silicon optical core in a segment of the planar optical waveguide including the segment of the silicon optical core;
wherein at least two of the p-n junctions are configured to be reverse biased by applying a voltage across the biasing electrodes;
wherein the optical phase shifter is configured to control a phase of the optical signal propagating through the planar optical waveguide by changing carrier densities at the at least two of the p-n junctions, due to varying the voltage, to alter a refractive index of the planar optical waveguide;
wherein the at least two of the p-n junctions comprise two reverse-biased p-n junctions offset from a lateral center of the silicon optical core in the segment thereof, and a single reverse-biased p-n junction aligned with the lateral center.