Passive Waveguide Grounding in Monolithic Optical Integration
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Solution Overview
Problem
Existing semiconductor optical integrated devices face challenges in suppressing the flow of leakage current from forward-biased optical devices into mirrors, which leads to broadening of the spectrum width.
Innovation Solution
A semiconductor optical integrated device is designed with a passive waveguide portion between the forward-biased optical device and the semiconductor laser, and a ground electrode on the lower surface of the semiconductor substrate, effectively routing the leakage current to the ground and preventing its entry into the mirror.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a forward-biased optical device is monolithically integrated with a semiconductor laser, then device functionality and compactness are improved, but leakage current flows into the mirror causing spectrum width broadening
Solution Approach 1:
A passive waveguide portion is introduced as an intermediary component between the forward-biased optical device and the semiconductor laser. This passive waveguide serves as a physical barrier that blocks leakage current from the forward-biased device from reaching the mirror, while still allowing optical signals to pass through. The passive waveguide portion includes a passive waveguide electrode electrically connected to ground, creating an electrical barrier without compromising optical functionality.
Solution Approach 2:
The waveguide structure is segmented into distinct functional portions: an active waveguide portion for light propagation, and a passive waveguide portion for current blocking. This segmentation allows the system to simultaneously achieve compact integration and leakage current suppression by dividing the waveguide into zones with different electrical properties.
2Area of stationary object
If the forward-biased optical device is placed close to the semiconductor laser for compact integration, then device size is reduced, but leakage current easily enters the mirror
Solution Approach 1:
The passive waveguide portion acts as an intermediary structure that enables close proximity integration while maintaining current isolation. It provides both optical guidance and electrical blocking functions, allowing the forward-biased optical device to be positioned near the laser without compromising reliability.
Solution Approach 2:
The passive waveguide electrode is electrically connected to ground, creating an equipotential region that prevents potential differences from driving leakage current into the mirror. This grounding strategy ensures that even when devices are closely integrated, electrical isolation is maintained through the grounded passive waveguide structure.
Data Source
AI summary
A semiconductor optical integrated device in which a forward-bias optical device and a semiconductor laser are monolithically integrated on a semiconductor substrate, includes: a passive waveguide portion that is arranged between the forward-bias optical device and the semiconductor laser; and a ground electrode that is arrange on a lower surface of the semiconductor substrate. Further, the semiconductor laser includes a mirror having a length on a side closer to the forward-bias optical device, the forward-bias optical device includes a forward-bias optical-device electrode on a side opposite to a side in contact with the semiconductor substrate, the passive waveguide portion includes a passive waveguide electrode on a side opposite to a side in contact with the semiconductor substrate, and the passive waveguide electrode is electrically connected to the ground electrode.