Semiconductor Chip Output Groove for Low-Reflection Optical Mounting
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Solution Overview
Problem
Conventional semiconductor chips with integrated semiconductor optical amplifiers face challenges in achieving high output characteristics and stable operation due to issues with reflected return light and manufacturing variations, leading to decreased yield and optical loss.
Innovation Solution
The semiconductor chip incorporates a waveguide terminated inside at the output end portion with a window region and an open groove formed by dry etching, allowing for accurate alignment of the emission end face and reducing the impact of cleavage position errors, thereby minimizing reflected return light and optimizing optical output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a semiconductor optical amplifier (SOA) is integrated into a DFB laser with an EA modulator, then the optical output power is improved, but the reflected return light significantly deteriorates the operating characteristics
Solution Approach 1:
The harmful reflected return light is extracted and removed from the optical path by introducing an optical filter that selectively transmits the desired wavelength while blocking reflected light. This separates the useful optical signal from the harmful reflection, allowing high output power to be maintained without deteriorating operating characteristics.
Solution Approach 2:
An optical filter is introduced as an intermediary element between the SOA and the optical output. This mediator selectively filters out reflected return light while allowing the desired optical signal to pass through, thus protecting the operating characteristics while maintaining high output power.
2Reliability
If a window structure and bent waveguide are combined to suppress reflected return light, then the operating characteristics are improved, but the manufacturing precision is significantly affected by cleavage position errors
Solution Approach 1:
The mechanical cleavage method is replaced with a lithographically defined waveguide structure. Instead of relying on precise mechanical cleavage positioning, the waveguide geometry and optical filtering are defined by photolithography patterns, which can be manufactured with much higher precision and repeatability using standard semiconductor fabrication processes.
Solution Approach 2:
The approach changes from geometric suppression (relying on precise waveguide angles and positions) to spectral filtering (relying on wavelength-selective optical filtering). This parameter change from spatial to spectral domain allows for more robust manufacturing tolerances while achieving the same goal of suppressing reflected return light.
3Object-affected harmful factors
If the waveguide is bent to suppress reflected return light, then the reflection is reduced, but the light emission angle increases requiring larger mounting area
Solution Approach 1:
Instead of bending the waveguide to redirect light, the harmful reflected return light is extracted and removed using an optical filter. This allows the waveguide to remain straight, maintaining a compact footprint while still suppressing reflections through wavelength-selective filtering.
Solution Approach 2:
An optical filter serves as an intermediary that suppresses reflected return light without requiring changes to the waveguide geometry. This mediator enables reflection suppression while keeping the light emission angle small, thus reducing the required mounting area.
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 design enhances the yield and stability of semiconductor chips by reducing optical loss and improving mounting efficiency, allowing for higher output characteristics and reduced man-hours and occupied area in optical modules.
Implementation Method 1
an open groove formed by dry etching... minimizing reflected return light
Implementation Method 2
an open groove formed by dry etching
Data Source
AI summary
Provided is a semiconductor chip that can reduce the man-hours for mounting on an optical module, a subcarrier, or the like, and reducing the dedicated area of the subcarrier or the like. The semiconductor chip includes a waveguide that is terminated inside at an output end portion from which light is emitted, without contacting an emission end face, and a window region made of a bulk semiconductor and disposed between the waveguide and the emission end face, wherein the semiconductor chip is provided with an open groove formed in the output end portion so that the emission end face is a side wall formed by etching.