Receiver Optical Module Capacitor Disposing Block
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Solution Overview
Problem
High frequency signal characteristics in optical receiver modules are compromised by impedance mismatch and non-uniform wiring, especially in multi-channel waveguide photodetectors, leading to degraded 3 dB bandwidth and increased costs due to complex integration of capacitors within the photodetector or on its surface.
Innovation Solution
A capacitor disposing block is used to uniformly position capacitors relative to photodetectors, acting as a common ground and reducing impedance mismatch by ensuring consistent bonding wire lengths and shapes, thereby stabilizing the ground voltage and enhancing high frequency signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitor is integrated within a photodetector or on its surface, then high frequency signal characteristics are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent transitions from two-dimensional planar integration of capacitors on the photodetector surface to three-dimensional vertical stacking, where capacitors are positioned above the photodetector array. This dimensional change enables uniform wiring connections while simplifying the manufacturing process by avoiding complex lateral routing and large capacitor pad formations.
2Device complexity
If capacitors are disposed on the side surface of a waveguide photodetector, then integration complexity is reduced, but uniformity of high frequency characteristics across channels deteriorates
Solution Approach 1:
The patent positions capacitors in the vertical dimension above the photodetector array rather than on the lateral surface. This enables each photodetector channel to connect to its corresponding capacitor through vertically-aligned wiring, ensuring uniform bonding wire lengths and shapes across all channels while maintaining simple integration.
Solution Approach 2:
The patent employs an asymmetric vertical stacking arrangement where capacitors are positioned at specific heights above each photodetector channel. This asymmetric positioning in the vertical dimension allows for optimized wiring paths that maintain uniformity across channels while avoiding the symmetry constraints of planar layouts.
3Ease of manufacture
If wire bonding is used to connect photodetectors and capacitors, then manufacturing flexibility is improved, but impedance mismatch and signal quality degradation occur
Solution Approach 1:
The patent utilizes vertical wire bonding in the third dimension to connect photodetectors to capacitors. This vertical bonding approach shortens the bonding wire length compared to lateral connections, reduces the bonding area, and minimizes inductance effects. The vertical arrangement also improves impedance matching by reducing the loop area and optimizing the electrical path between photodetector and capacitor.
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 ensures uniform high frequency signal characteristics across channels, reduces manufacturing complexity and costs, and enhances the 3 dB bandwidth of the optical receiver module, while maintaining a stable ground for the photodetector and transimpedance amplifier.
Implementation Method 1
LC resonance may be generated by a photodetector, a capacitor and a bonding wire between the photodetector and the capacitor, by which 3 dB band width characteristics of an OE response of a module can be enhanced
Implementation Method 2
an optical receiver module receiving a signal of 10 Gbps or higher should be designed and manufactured in consideration of loss, reflection, and resonance of a high frequency signal with respect to module components
Data Source
AI summary
There is provided a receiver optical module including a photodetector having a plurality of channels, a capacitor disposing block formed on an upper portion of the photodetector, a plurality of capacitors formed on the capacitor disposing block, and an electrical wiring configured to connect the plurality of capacitors to electrodes of a plurality of channels of the photodetector, wherein the plurality of capacitors are formed on the capacitor disposing block such that distance between the capacitors and the electrodes of the corresponding channels are the same. Distortion and loss of signal characteristics of high frequency can be reduced and quality of a signal can be enhanced.