RF delay line for segmented optical waveguide modulator
AssigneeNokia Solutions and Networks Oy
InventorsDouglas Gill, Juthika Basak, Asres Seyoum, Matthew Streshinsky
Life of this patent
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Abstract
A segmented optical modulator includes two optical modulator segments located along a main face of a photonic chip, and two RF transmission lines connected to drive a corresponding one of the two optical modulator segments. A signal electrode of one of the transmission lines includes a segment that is vertically capacitively coupled to a plurality of spaced ground-connected metallic elements disposed in sequence along a length of the segment above or below thereof so as to be capacitively coupled thereto.
Claims18
An apparatus, comprising:
- a photonic chip having a planar top face and comprising a segmented optical modulator having a plurality of optical waveguide modulation segments, the optical waveguide modulation segments being located along the top face and being optically connected in series;
- and
- a vertical stack, at least, including:
- a first layer comprising a plurality of separate metallic radio frequency (RF) transmission lines therein, the plurality of separate metallic RF transmission lines being electrically connected in parallel such that each one of the plurality of separate metallic RF transmission lines carries a separate copy of an RF input signal with each separate metallic RF transmission line being connected to a separate, corresponding one of the plurality of optical waveguide modulation segments such that each separate metallic RF transmission line drives only the separate, corresponding one of the plurality of optical waveguide modulation segments to which it is connected;
- a second layer extending along and separate from the first layer and comprising at least two separate distributed metallic structures therein, each one of the at least two distributed metallic structures being capacitively coupled to an adjacent one of the plurality of separate metallic RF transmission lines to set a propagation time delay for the input RF signal carried by the capacitively coupled metallic RF transmission line, such that each one of the at least two distributed metallic structures only affects the propagation time delay of the input RF signal driving the corresponding one of the optical waveguide modulation segments to which the capacitively coupled metallic RF transmission line is connected;
- and
- an electrical insulating layer located between the first and second layers.
A segmented optical modulator comprising:
- a photonic chip having a planar top face and comprising:
- an optical modulator including two optical waveguide modulation segments located along the top face and optically connected in series;
- first and second radio frequency (RF) transmission lines comprising respective signal electrodes and being connected in parallel to carry respective separate copies of an RF input signal to separately drive the two optical waveguide modulation segments therewith, the signal electrodes of the first and second RF transmission lines being physically separate from each other;
- and
- a plurality of spaced apart and ground-connected metallic segments aligned along a segments of the signal electrode of the second RF transmission line, being capacitively coupled thereto and being located between the planar top face and the second RF transmission line to shield the segment of the second RF transmission line from environment above the planar top face of the photonic chip.
Dependencies are inferred from the claim text.