Optical Modulator Package Size Reduction via Folded Wiring
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Solution Overview
Problem
Conventional optical modulators face a challenge due to the increased size of the wiring substrate resulting from numerous wire turns, which in turn enlarges the package size, leading to inefficiencies in optical modulation and phase adjustment.
Innovation Solution
The optical modulator design incorporates a first substrate with Mach-Zehnder optical waveguides and signal electrodes, a second substrate with signal line paths, and a flexible circuit board outside the package, allowing for equivalent optical path lengths and electrical signal distribution to reduce package size by optimizing signal path lengths and using a flexible circuit board for external signal connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wires are disposed to have numerous turns on the wiring substrate to adjust phase differences among high-frequency electrical signals, then the phase adjustment capability is improved, but the size of the wiring substrate increases
Solution Approach 1:
The patent transitions from a two-dimensional planar wiring substrate to a three-dimensional structure by folding the wiring substrate. This allows the wires to achieve the necessary electrical length for phase adjustment without occupying excessive area on a single plane. The folded configuration enables the wiring substrate to fit within a compact package while maintaining the required signal path lengths.
Solution Approach 2:
The wiring substrate is designed with flexible, foldable sections that can be dynamically configured. This dynamic structure allows the substrate to adapt its shape to fit within the package constraints while maintaining the necessary wire lengths for phase adjustment. The flexibility enables the system to achieve both compact packaging and proper signal timing.
2Ease of operation
If the wiring substrate size increases due to numerous wire turns, then the phase differences among high-frequency electrical signals can be adjusted, but the package size increases
Solution Approach 1:
By folding the wiring substrate into three-dimensional space, the patent achieves the necessary wire lengths for phase adjustment without increasing the planar footprint. This vertical/dimensional arrangement allows the package to remain compact while accommodating the extended signal paths required for high-frequency phase control.
Solution Approach 2:
The folded wiring substrate is nested within the package structure, with multiple layers and sections arranged in a compact, space-efficient manner. This nesting approach allows the extended wiring paths to be contained within the package volume without increasing its external dimensions.
3Ease of manufacture
If a flexible wiring board is used as a wiring substrate, then the ease of manufacture is improved, but the wires still require numerous turns increasing the substrate size
Solution Approach 1:
The patent combines the manufacturing advantages of flexible wiring boards with a folded three-dimensional configuration. This allows the substrate to be manufactured using standard flexible PCB techniques while achieving compact dimensions through spatial folding, thus maintaining both ease of manufacture and small size.
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
This configuration enables reduced package size, maintains equivalent electrical signal timing across optical modulating units, and achieves high-speed optical responsiveness while minimizing propagation loss and band degradation.
Implementation Method 1
a first substrate that has a Mach-Zehnder optical waveguide that is formed on a substrate having an electro-optical effect
Data Source
AI summary
An optical modulator includes a package that accommodates therein a first substrate and a second substrate different from the first substrate, and outside the package, a flexible circuit board. The first substrate has plural optical modulating units disposed thereon in parallel and each including a Mach-Zehnder optical waveguide. Plural first signal line paths corresponding to the optical modulating units are disposed on the second substrate. Plural second signal line paths corresponding to the optical modulating units are disposed on the flexible circuit board. Electrical lengths of the second signal line paths are different from one another. Electrical lengths of signal paths that span from input ends of the second signal line paths corresponding to the optical modulating units to base points on signal electrodes, via the first signal line paths, are equal to one another.