Optical Transmitter Assembly Vertical Coupling
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Solution Overview
Problem
Conventional silicon photonics (SiP) chips cannot generate light at typical optical communication wavelengths and require external light sources, necessitating an optical transmitter assembly that can efficiently couple light from a semiconductor laser diode into the chip while protecting the diode and preventing back reflections.
Innovation Solution
An optical transmitter assembly comprising a substrate with a laser diode, a turning mirror, and a polarization processing element, where the laser diode and polarization processing element are positioned on opposing sides of the substrate, and the turning mirror redirects the light beam through the substrate for vertical coupling into a planar integrated circuit, with a microlens for collimation or focusing and a cavity for housing polarization components to prevent back reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical transmitter assembly is designed to protect the laser diode from environmental factors and back reflections, then the reliability of the system is improved, but the device complexity increases due to additional protective components and enclosures
Solution Approach 1:
The patent combines multiple protective functions (environmental protection and back reflection prevention) into a single integrated optical transmitter assembly structure. The enclosure houses both the laser diode protection and the optical isolator, merging protective elements into one unified device that couples light vertically into the SiP chip.
Solution Approach 2:
The optical isolator acts as an intermediary component that prevents back reflections from reaching the laser diode while allowing forward light propagation. This mediator component protects the laser diode without requiring direct physical barriers between the diode and the optical path.
2Reliability
If expensive polarization processing components are installed in the optical transmitter assembly, then the performance and reliability are improved, but the manufacturing cost increases
Solution Approach 1:
The optical transmitter assembly is segmented into modular components, with the polarization processing element as a separate installable component. This allows selective installation of expensive polarization components only when needed for specific applications, rather than including them in all assemblies, thereby reducing overall manufacturing costs while maintaining performance where required.
Solution Approach 2:
The patent allows the optical transmitter assembly to be manufactured and tested without the polarization processing element initially installed. This preliminary action enables quality assurance and functionality verification before the expensive polarization component is added, reducing the risk of damage during assembly and allowing cost optimization based on actual performance requirements.
3Area of stationary object
If the optical transmitter assembly uses a compact design with small footprint, then the area occupied is reduced, but the ease of manufacturing and assembly becomes more difficult
Solution Approach 1:
The patent employs vertical coupling of light into the SiP chip, transitioning from traditional lateral coupling to a vertical dimension. This dimensional change allows for a compact footprint on the chip surface while maintaining adequate space for the laser diode, enclosure, and optical components in the vertical stacking arrangement, thus reducing overall area without significantly complicating manufacturing.
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 assembly effectively couples light into the SiP chip, protects the laser diode from environmental and back reflections, and reduces the footprint and cost by allowing for selective installation of expensive polarization components only after testing, enhancing coupling efficiency and reducing the risk of damage.
Implementation Method 1
a turning mirror provided at the first face of the substrate and configured to re-direct the light beam to propagate through the substrate emerging from the second face
Implementation Method 2
a first microlens disposed between the LD and the turning mirror and configured to at least partially collimate or focus the light beam
Implementation Method 3
a polarization processing element may be disposed in a cavity in the supporting substrate
Data Source
AI summary
The invention relates to an optical transmitter assembly (OTA) for vertical coupling of light into a chip, and to a method for manufacturing the OTA. The OTA includes a laser diode, a microlens and a turning mirror mounted at a top face of a supporting substrate within a sealed enclosure, and an optical component, such as an optical isolator, a polarizer, or a microlens disposed in a substrate cavity that opens to the back face of the substrate. The optical component may be placed into the cavity after the enclosure is sealed.