Optical Modulator Module Impedance Matching Design
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Solution Overview
Problem
Existing optical modulator modules face challenges in achieving high-frequency characteristics while maintaining mounting performance, particularly due to limitations in space and impedance mismatching, which degrade reflecting and transmitting characteristics at high-speed modulation bands.
Innovation Solution
The optical modulator module incorporates a conductive package with electrical continuity to the ground electrode, a substrate with signal and ground electrodes, and a lead pin connecting the signal electrode to the substrate, optimizing the layout to ensure proper impedance matching and grounding without the need for spacers, thereby enhancing high-frequency performance and mounting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If surface-mounting type components are used to improve mounting performance, then ease of operation is improved, but high-frequency characteristics deteriorate due to impedance mismatching and space limitations
Solution Approach 1:
A flexible substrate is introduced as an intermediary component between the optical modulator and the rigid circuit board. This flexible substrate acts as a mediator that can adapt to both the mounting requirements and the high-frequency signal transmission needs, resolving the contradiction between ease of mounting and high-frequency performance
Solution Approach 2:
The characteristic impedance of the flexible substrate is specifically designed to be 50Ω, matching the standard high-frequency interface. By changing and optimizing the impedance parameter of the connecting medium, the patent achieves both easy surface-mounting compatibility and excellent high-frequency characteristics without degradation
2Reliability
If spacers are interposed between package and flexible substrate to alleviate impedance mismatching, then high-frequency characteristics are improved, but device complexity and space requirements increase
Solution Approach 1:
The patent removes the spacer component from the structure entirely. Instead of adding a spacer to achieve impedance matching, the flexible substrate itself is designed with the appropriate impedance characteristics, extracting the unnecessary intermediary component and simplifying the overall structure
Solution Approach 2:
The flexible substrate serves multiple functions simultaneously: it provides mechanical support, enables surface-mounting connectivity, and maintains 50Ω impedance for high-frequency signals. This multi-functionality eliminates the need for separate spacer components, reducing structural complexity while achieving impedance matching
3Ease of manufacture
If lead pin is solder-connected parallel on the signal electrode pad, then ease of manufacture is improved, but space constraints are worsened due to limited mounting area
Solution Approach 1:
The flexible substrate allows the lead pin connection to be made in a different spatial dimension and orientation. Instead of being constrained to parallel surface mounting that consumes horizontal space, the flexible nature enables connections that utilize vertical and angled dimensions, reducing the footprint on the circuit board
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 allows for improved high-frequency characteristics and mounting performance while reducing space constraints, maintaining desired impedance values and suppressing degradation of S parameters, even at high-speed modulation bands like 20 Gbps and 40 Gbps.
Implementation Method 1
a conductive package configured to accommodate the optical modulator and have electrical continuity with the ground electrode of the optical modulator
Implementation Method 2
have a ground electrode on a first surface thereof electrically connected to the package by solder or a conductive adhesive
Implementation Method 3
a lead pin configured to electrically connect the signal electrode of the optical modulator to the signal electrode of the substrate
Data Source
AI summary
Disclosed is an optical modulator module including an optical modulator configured to have a signal electrode and a ground electrode; a conductive package configured to accommodate the optical modulator and have electrical continuity with the ground electrode of the optical modulator; a substrate configured to have a ground electrode on a first surface thereof electrically connected to the package by solder or a conductive adhesive and have a signal electrode on another surface thereof; and a lead pin configured to electrically connect the signal electrode of the optical modulator to the signal electrode of the substrate.