SOA Light Combiner Architecture for High-Power Coherent PICs
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Solution Overview
Problem
High-power photonic integrated circuits face challenges in integrating high-power components without gain saturation and two-photon absorption effects, limiting their performance in applications like LIDAR.
Innovation Solution
Implementing a parallel semiconductor optical amplifier combiner architecture with silicon and silicon nitride waveguides for phase matching and coherent combining, using a monitor photodiode for closed-loop control to minimize current and reduce two-photon absorption, allowing for higher optical power handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single semiconductor optical amplifier is used to increase optical power, then the optical power output increases, but gain saturation effects occur limiting further power increase
Solution Approach 1:
The patent divides a single high-power amplifier into multiple parallel lower-power amplifiers. Each amplifier operates below its saturation point, and their outputs are coherently combined to achieve high total power output without individual gain saturation. This is implemented through multiple SOA channels that are phase-controlled and combined using optical couplers.
Solution Approach 2:
The patent merges outputs from multiple semiconductor optical amplifiers through coherent combining. By controlling the phase relationships between amplifiers and combining their outputs optically, the system achieves power levels that would cause saturation in a single amplifier while maintaining efficient operation of each individual amplifier.
2Power
If optical power is increased in photonic integrated circuits, then LIDAR ranging and detection performance improve, but two-photon absorption effects increase causing loss
Solution Approach 1:
The patent segments the high-power optical signal into multiple parallel channels, each carrying a fraction of the total power. This segmentation prevents any single waveguide from experiencing excessive two-photon absorption, as each channel operates at lower power levels where nonlinear losses are reduced.
Solution Approach 2:
The patent transitions from a single high-power channel to multiple parallel channels, effectively adding a spatial dimension to the power distribution. This dimensional expansion allows the system to achieve high total power while keeping individual channel powers low enough to avoid significant two-photon absorption effects.
3Power
If multiple semiconductor optical amplifiers are integrated in parallel, then higher optical power is achieved, but device complexity increases
Solution Approach 1:
The patent employs universal phase control mechanisms that can be applied across multiple amplifier channels. The same phase modulation and control techniques are reused in each channel, reducing the need for channel-specific complex circuitry and allowing scalable integration of additional amplifiers with minimal increase in overall system complexity.
Solution Approach 2:
The patent implements feedback control systems that monitor and adjust the phase and power of each amplifier channel. This feedback mechanism automatically compensates for variations and maintains optimal coherent combining conditions, reducing the need for manual calibration and simplifying the integration of multiple amplifiers by providing self-correcting operation.
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 approach enables low-loss, high-power photonic integrated circuits that can handle significantly higher optical powers than traditional designs, overcoming gain saturation and two-photon absorption limitations, and scaling to integrate multiple semiconductor optical amplifiers for enhanced performance.
Implementation Method 1
splitting the beam into a first beam and a second beam using the optical splitter
Implementation Method 2
amplifying the first beam and the second beam using a pair of semiconductor optical amplifiers
Implementation Method 3
phase shifting the first beam using a phase shifter in the photonic integrated circuit
Implementation Method 4
combining the first beam and the second beam using an optical combiner to form a combined beam
Implementation Method 5
detecting an optical coherence of the combined beam using a photodetector that measures a current of the combined beam
Data Source
AI summary
Disclosed is a coherent optical combining photonic integrated circuit that can detect and align light amplified by a scalable quantity of semiconductor optical amplifiers (SOAs). The light can be split into beams and amplified by individual SOAs in a PIC and combined via couplers in the PIC. The combined light can be measured using a photodetector and the light beams can be adjusted based the photodetector measurement to coherently combine the light to achieve high optical power from the photonic integrated circuit.