Optical Modulator Floating Conductor RF Loss
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Solution Overview
Problem
Optical modulators face RF loss and mechanical durability issues due to excitation of substrate modes, which are exacerbated by reducing substrate thickness to avoid resonant dips outside the operating frequency range.
Innovation Solution
Incorporating a floating conductor between substrates to suppress RF dielectric and parallel-plate modes, allowing for a thinner effective thickness to reduce parasitic losses while maintaining mechanical rigidity through a thicker mechanical thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If substrate thickness is reduced to shift RF loss and resonances to higher frequency, then RF loss is reduced and resonances move outside operating frequency range, but mechanical durability and mechanical rigidity are reduced
Solution Approach 1:
The substrate is segmented into multiple thinner substrate layers (first substrate layer, second substrate layer, third substrate layer) separated by floating conductors. This segmentation allows each layer to be thin enough to suppress RF dielectric modes and parallel-plate modes (reducing RF loss) while the stacked structure with floating conductors provides the necessary mechanical rigidity and durability.
Solution Approach 2:
Floating conductors are introduced as intermediary elements between the substrate layers. These floating conductors serve dual purposes: they electrically suppress parasitic RF modes by creating capacitive coupling that shifts resonance frequencies, and they mechanically connect the thin substrate layers to maintain structural integrity and rigidity.
2Object-generated harmful factors
If substrate thickness is reduced to suppress parasitic RF modes, then RF dielectric modes and parallel-plate modes are suppressed, but mechanical rigidity is reduced making manufacture more difficult
Solution Approach 1:
The substrate is divided into multiple thin layers with floating conductors in between. Each thin layer individually suppresses parasitic RF modes while the composite stacked structure maintains the mechanical rigidity needed for manufacturing and handling.
Solution Approach 2:
The substrate structure becomes a composite of multiple substrate layers and floating conductor layers. This composite structure combines the electromagnetic properties of thin layers (suppressing parasitic modes) with the mechanical properties of the stacked assembly (providing rigidity and ease of manufacture).
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses parasitic RF losses and maintains mechanical durability, ensuring the optical modulator operates within its intended frequency range with improved manufacturability.
Implementation Method 1
The laminated substrate may include a conductor layer to suppress radio frequency (RF) dielectric modes and parallel-plate modes within the laminated substrate
Implementation Method 2
The laminated substrate may include a conductor layer to suppress radio frequency (RF) dielectric modes and parallel-plate modes within the laminated substrate
Implementation Method 3
RF power in the fundamental electromagnetic mode of the set of coplanar waveguides can couple to the substrate modes, which may cause RF loss and/or resonant dips in an optical modulator frequency response
Data Source
AI summary
An optical modulator may include at least one ground electrode. The optical modulator may include at least one signal electrode parallel to the at least one ground electrode. The optical modulator may include at least one waveguide parallel to the at least one ground electrode and the at least one signal electrode. The optical modulator may include a first substrate disposed underneath the at least one ground electrode and the at least one signal electrode relative to a surface of the optical modulator. The optical modulator may include a second substrate disposed underneath at least a portion of the first substrate relative to the surface of the optical modulator. The optical modulator may include a floating conductor disposed between the first substrate and the second substrate.