Monolithic InP PIC with On-Chip Laser Alignment Diagnostics
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Solution Overview
Problem
The existing fiber-to-PIC alignment process is cumbersome and limits production station throughput due to the need for multiple stages and complex equipment usage, such as complex lasers and external photodetectors, which increases costs and reduces efficiency.
Innovation Solution
A monolithic InP-based photonic integrated circuit (PIC) with an auxiliary photonic circuit that includes a semiconductor optical amplifier (SOA) and a laser unit, allowing for on-chip generation of laser light for alignment and diagnostics, reducing the need for external components and simplifying the alignment process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a three-stage alignment process (first light stage, active alignment stage, coupling measurement stage) is used to optimize fiber-to-PIC alignment, then alignment accuracy is improved, but production throughput is reduced and process complexity increases
Solution Approach 1:
The patent combines the first light stage and active alignment stage into a single integrated alignment process. The auxiliary photonic circuit generates laser light that automatically guides the alignment process, eliminating the need for separate manual positioning and active optimization stages. This merging reduces the number of process steps while maintaining alignment accuracy through the self-guiding laser light feature.
Solution Approach 2:
The auxiliary photonic circuit provides self-service by generating its own laser light for alignment purposes. This on-chip laser light eliminates the need for external light sources and complex alignment equipment, allowing the PIC to perform its own alignment guidance function. The system serves itself by using integrated components rather than requiring external support systems.
2Measurement precision
If external optical measurement equipment and complex lasers are used for alignment, then alignment precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the light generation function from external equipment and places it directly on the PIC chip through the auxiliary photonic circuit. By taking out the laser source from external equipment and integrating it onto the chip, the system eliminates the need for complex external optical measurement equipment while maintaining alignment precision through the on-chip laser guidance.
Solution Approach 2:
The auxiliary photonic circuit serves multiple functions: it generates laser light for alignment, provides diagnostic capabilities, and enables self-testing of the PIC. This multi-functionality replaces what would traditionally require separate external equipment for alignment, diagnostics, and testing, thereby reducing overall system complexity while maintaining or improving performance.
3Loss of energy
If multiple alignment stages with external equipment are implemented, then coupling loss optimization is improved, but manufacturing cost and time increase
Solution Approach 1:
The auxiliary photonic circuit performs preliminary action by generating laser light that pre-establishes the optimal alignment path before the actual coupling process. This preliminary light guidance allows for rapid positioning and alignment without requiring multiple iterative measurement and adjustment stages, thereby reducing both time and the number of process steps needed to achieve optimal coupling loss.
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 improves the throughput of the fiber-to-PIC alignment process by enabling efficient on-chip generation of laser light for alignment and diagnostics, reducing component count, and lowering costs while maintaining high alignment accuracy.
Implementation Method 1
a first semiconductor optical amplifier, SOA, having a first end facet that is arranged in optical communication with the third optical interface of the first optical splitter-combiner unit, and a second end facet that is arranged in optical communication with the first laser unit
Data Source
AI summary
A monolithic InP-based PIC having a first photonic assembly that has a first optical splitter-combiner unit having a first end part that is optically connected with a first optical waveguide and a second end part that is optically connected with a first main photonic circuit and a first auxiliary photonic circuit. The first auxiliary photonic circuit has a first laser unit, and a first SOA. The first SOA is configurable to be in a first operational state in which the first SOA allows optical communication between the first laser unit and the first optical splitter-combiner unit, or a second operational state in which the first SOA prevents optical communication between the first laser unit and the first optical splitter-combiner unit. An opto-electronic system including the PIC.