Optical Module Monolithic Integration for Compact Footprint
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Solution Overview
Problem
Existing optical modules face challenges in size reduction, cost increase, and difficulty in achieving external electrical connection due to the lateral alignment of optical parts and the need for multiple manufacturing steps, which complicates the integration of semiconductor lasers with silicon photonics devices.
Innovation Solution
An optical module design where a semiconductor optical device with an active layer and mirror are monolithically integrated, allowing light to exit through a side opposite the electrode, with a sub-mount and spacer configuration that enables easy electrical connection and reduced manufacturing steps by forming wiring patterns only on specific surfaces, facilitating external electrical access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If optical parts are laterally aligned to ensure optical distance, then optical connection is achieved, but the dimension of the light source increases
Solution Approach 1:
The patent transitions from lateral alignment (horizontal dimension) to vertical stacking (vertical dimension) by placing the laser above the ball lens and using a reflection mirror to redirect light downward. This dimensional change achieves the required optical path length without increasing the horizontal footprint of the device.
2Manufacturing precision
If multiple manufacturing steps are added to align optical axes, then optical alignment precision is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines multiple optical components (laser, ball lens, reflection mirror) and their alignment functions into a single integrated optical module assembly. The reflection mirror serves dual purposes: redirecting light and providing a mounting surface for precise alignment, thereby reducing the number of separate manufacturing steps required.
Solution Approach 2:
The reflection mirror acts as an intermediary element that facilitates optical axis alignment between the laser and ball lens. By providing a defined reflection surface and mounting interface, it enables precise optical coupling without requiring complex direct alignment procedures between the laser and lens.
3Volume of moving object
If optical parts are integrated to reduce size, then device compactness is improved, but ease of external electrical connection deteriorates
Solution Approach 1:
The patent segments the device into distinct functional layers: the optical module (laser, ball lens, mirror) is separated from the substrate, with electrical connections established through wire bonds that connect the laser electrode on the optical module to pads on the substrate. This segmentation allows compact optical integration while maintaining accessible electrical connection points.
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 design allows for a compact, cost-effective optical module with simplified manufacturing and efficient external electrical connection, enhancing the integration of semiconductor optical devices with silicon photonics while maintaining high coupling efficiency and heat dissipation.
Implementation Method 1
a mirror that reflects light having exited out of the active layer toward a side opposite the electrode
Implementation Method 2
The grating coupler is an optical part that uses Bragg reflection to convert the propagating direction of light with which the surface is irradiated into a direction in a plane of the device, focusing the light
Data Source
AI summary
An optical module includes a semiconductor optical device in which an active layer located at one side, an electrode located at the same side, and a mirror that reflects light toward the side opposite the electrode are monolithically integrated, a sub-mount having one surface on which a first wiring pattern is formed, a substrate in which an optical waveguide and a grating coupler are formed in a surface layer of the substrate, a spacer having an upper surface on which a second wiring pattern is formed, and a wire. The sub-mount is mounted on the spacer. The first wiring pattern on the sub-mount faces part of the second wiring pattern on the spacer and is electrically connected thereto. The second wiring pattern on the spacer includes a pad being disposed in a region exposed from the sub-mount and being bonded to the wire.