Silicon Photonic Chip Alignment Using Passive Optical Tap Feedback
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Solution Overview
Problem
Conventional active optical alignment methods for silicon photonically-enabled integrated circuits are costly, cumbersome, and inefficient, often requiring complex and time-consuming processes that introduce asymmetry.
Innovation Solution
The system employs passive optical taps with feedback loops to grating couplers, enabling active alignment of silicon photonically-enabled integrated circuits without powering them, using product-independent design rules and passive optical components like splitters and surface grating couplers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional active optical alignment methods are used, then alignment can be achieved, but the process becomes costly, cumbersome, and time-consuming
Solution Approach 1:
The patent incorporates alignment markers directly into the silicon photonic chip fabrication process, so that alignment features are pre-prepared during manufacturing rather than requiring complex alignment procedures during assembly. This preliminary action eliminates time-consuming alignment operations while maintaining precision.
Solution Approach 2:
The patent introduces optical alignment markers as intermediary elements that facilitate the alignment process. These markers serve as mediators between the optical components and the silicon photonic chip, enabling accurate alignment through optical detection of marker positions without requiring complex mechanical alignment procedures.
2Measurement precision
If conventional active optical alignment methods are used, then alignment can be achieved, but the process becomes complex and introduces asymmetry
Solution Approach 1:
Alignment markers are integrated into the chip fabrication process, pre-establishing reference features that simplify the alignment process. This eliminates the need for complex alignment procedures and reduces asymmetry in the alignment approach.
Solution Approach 2:
The patent uses uniform optical alignment markers that can be applied consistently across all chips and components, creating a homogeneous alignment process. This reduces complexity by standardizing the alignment approach and eliminating asymmetric or ad-hoc alignment procedures.
3Ease of operation
If optical impedance elements are used for alignment, then alignment is facilitated, but the element must be switched between transmissive and non-transmissive states
Solution Approach 1:
The patent extracts the alignment function from the main optical impedance elements and implements it through separate alignment markers. This separation allows the impedance elements to maintain their primary function while alignment is achieved through the dedicated markers, reducing the complexity of switching states.
Solution Approach 2:
Alignment markers serve as intermediary elements that facilitate alignment without requiring the main optical impedance elements to switch between transmissive and non-transmissive states. The markers provide a dedicated alignment pathway that simplifies the operation of the primary optical components.
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 allows for cost-effective, scalable, and accurate active optical alignment, independent of specific product designs, facilitating both packaging and testing of silicon photonically-enabled integrated circuits while ensuring alignment stability.
Implementation Method 1
An optical tap may be provided in an optical waveguide of the silicon photonically-enabled integrated circuit. The optical tap may be configured to direct a portion of an optical signal received by the waveguide to an alignment marker.
Implementation Method 2
The optical tap may be configured to direct a portion of an optical signal received by the waveguide to an alignment marker. The alignment marker may be configured to emit an optical signal.
Data Source
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AI summary
Methods and systems for optical alignment to a silicon photonically-enabled integrated circuit may include aligning an optical assembly to a photonics die comprising a transceiver by, at least, communicating optical signals from the optical assembly into a plurality of grating couplers in the photonics die, communicating the one or more optical signals from the plurality of grating couplers to optical taps, with each tap having a first output coupled to the transceiver and a second output coupled to a corresponding output grating coupler, and monitoring an output optical signal communicated out of said photonic chip via said output grating couplers. The monitored output optical signal may be maximized by adjusting a position of the optical assembly. The optical assembly may include an optical source assembly comprising one or more lasers or the optical assembly may comprise a fiber array. Such a fiber array may include single mode optical fibers.