Optical Transmission Module With GRIN Coupling for Low-Loss Alignment
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Solution Overview
Problem
Conventional optical transmission technology faces challenges with poor optical coupling efficiency and signal loss due to manufacturing tolerances, air gaps, and intersecting wires causing interference.
Innovation Solution
The optical transmission module incorporates a substrate with an optical transmission channel and refractive portions, featuring first reflective surfaces and progressive refractive indices. This design includes an optical transmitter and receiver with wire bonding connections, and optionally, a light guide mechanism to improve alignment and signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the light emitting surface and I/O pads are arranged at the same side of the optical transmitter, then the structure is simplified and manufacturing is easier, but manufacturing tolerances cause misalignment between the light emitting surface and the optical waveguide, resulting in poor optical coupling efficiency and signal loss
Solution Approach 1:
The patent introduces an optical coupling structure (including lens arrays, waveguides, or reflective surfaces) as an intermediary component between the light emitting surface and the optical waveguide. This intermediary compensates for misalignment caused by manufacturing tolerances by providing optical path correction and positioning adjustment mechanisms, thereby maintaining high coupling efficiency while preserving the simplified side-arranged configuration.
Solution Approach 2:
The patent employs adjustable parameters such as the refractive index of coupling materials, the focal length of lens arrays, and the positioning depth of the light emitting surface to optimize optical coupling. By changing these parameters, the system can compensate for manufacturing variations and achieve precise alignment without requiring extremely tight manufacturing tolerances.
2Ease of operation
If an air gap exists between the optical waveguide board and the optical transmitter, then assembly is easier and thermal management is improved, but the divergence angle of light increases, resulting in high loss and low optical coupling efficiency
Solution Approach 1:
The patent introduces an optical coupling structure as an intermediary that bridges the air gap between the optical waveguide board and the optical transmitter. This intermediary includes components such as lens arrays, gradient index (GRIN) lenses, or reflective surfaces that capture divergent light from the transmitter and redirect it into the waveguide, thereby reducing optical loss while maintaining the benefits of the air gap for assembly and thermal management.
Solution Approach 2:
The patent employs curved optical surfaces such as spherical or aspherical lens surfaces to focus and redirect divergent light. The curved surfaces are designed to match the divergence angle of light from the transmitter, converting the divergent beam into a focused beam that couples efficiently into the waveguide, thereby reducing optical loss while preserving the air gap configuration.
3Reliability
If wires are connected between the optical transmitter and driver, then electrical connection is established, but the wires intersect with each other causing signal interference and poor transmission effect
Solution Approach 1:
The patent implements differential signaling and localized shielding around wire pairs to reduce electromagnetic interference. By providing each wire pair with dedicated shielding and using differential voltage signaling, the system minimizes the impact of intersecting wires and external interference, thereby maintaining reliable electrical connection while reducing signal interference.
Solution Approach 2:
The patent employs three-dimensional wire routing and stacking techniques to reduce wire intersections. By routing wires in multiple layers and using vertical interconnects, the system minimizes the number of wire crossings and reduces electromagnetic coupling between adjacent wires, thereby reducing signal interference while maintaining reliable electrical connection.
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 achieves low loss and good signal transmission effects by enhancing optical coupling efficiency through precise alignment and guiding of transmission signals, while reducing noise interference from wire connections.
Implementation Method 1
The optical transmission channel includes two first reflective surfaces respectively inclined to the thickness direction
Implementation Method 2
Each of the two refractive portions is provided with a progressive refractive index which is progressively increased or progressively decreased in the thickness direction
Data Source
AI summary
An optical transmission module is provided, including: a substrate, a transmitting side and a receiving side. The substrate defines a thickness direction and includes a optical transmission channel and two refractive portions located at two opposite sides of the optical transmission channel, and each of the two refractive portions is provided with a progressive refractive index progressively increased or decreased in the thickness direction. The transmitting side includes an optical transmitter and a driver, and the optical transmitter is electrically connected with the driver by wire bonding. The receiving side includes an optical receiver and a transimpedance amplifier, and the optical receiver is electrically connected with the transimpedance amplifier by wire bonding. At least one of the optical transmitter and the optical receiver includes a light transmission face and a conductive surface, and each said light transmission face faces toward one of the two refractive portions.