Optical Referencing With Drift Tracking for Silicon Photonics
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Solution Overview
Problem
Existing optical components require costly and complex temperature sensors for wavelength calibration and locking, which are difficult to integrate and increase size and complexity, and free space lockers are not integrable in silicon photonics chips.
Innovation Solution
A method for optical referencing using at least two optical devices with interference-based features, such as ring or disk resonators, that map drifts to an absolute wavelength scale without a temperature sensor, allowing integration within silicon photonics chips and reducing cost by eliminating the need for precise temperature sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are used for wavelength calibration and locking, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The optical reference device performs self-calibration by using its own spectral features as reference points. The system automatically tracks drift by comparing observed spectral positions with reference positions, eliminating the need for external temperature sensors or manual calibration interventions.
Solution Approach 2:
The patent replaces the mechanical/physical temperature sensor system with an optical-based drift tracking system. Instead of measuring temperature directly with sensors, the system uses optical spectral analysis to detect and compensate for wavelength drift, substituting a simpler optical measurement approach for complex thermal sensing.
2Reliability
If free space lockers are used for frequency locking, then reliability is improved, but ease of manufacture and integration worsen
Solution Approach 1:
The patent merges the frequency locking function directly into the silicon photonics chip by integrating the optical reference device and drift tracking circuitry with the laser source. This consolidation eliminates the need for separate free-space locker components and enables monolithic integration, making the system manufacturable using standard silicon photonics processes.
Solution Approach 2:
The patent introduces an optical reference device as an intermediary element that mediates between the laser source and the control system. This reference device provides stable spectral features that enable frequency locking without requiring complex free-space optical paths, facilitating integration into compact silicon photonics platforms.
3Measurement precision
If accurate temperature sensors are positioned close to optical devices, then measurement precision is improved, but size and packaging complexity increase
Solution Approach 1:
The patent replaces the physical temperature sensor with an optical-based drift detection system. Instead of placing temperature sensors close to optical devices, the system uses spectral analysis of the optical reference device to detect wavelength shifts, eliminating the need for close-proximity thermal sensing and reducing package size.
Solution Approach 2:
The optical reference device serves its own calibration function by using its intrinsic spectral features as reference points. This self-service capability eliminates the need for external temperature sensors positioned close to the device, reducing packaging complexity and size while maintaining calibration accuracy.
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
Enables cost-effective integration of wavelength meter functions in silicon photonics chips, reducing size and complexity while maintaining accurate frequency control without additional frequency locking mechanisms.
Implementation Method 1
A method is described for optical referencing in an optical system including a plurality of optical devices with variable perturbative drift rates. The plurality of optical devices include any of ring or disk resonators, Mach-Zehnder or Michelson interferometers, Fabry-Perot etalons, Bragg gratings or thin-film filters.
Data Source
AI summary
Systems and methods provide optical referencing in an optical system including a plurality of optical devices with variable perturbative drift rates. A method includes, subsequent to determining a tuning rate of one or more interrogator devices, which are tunable, and subsequent to locking the plurality of optical devices including the one or more interrogator devices, detecting a drift in spectrum of the optical system based on a perturbation; and tracking the drift based on variable perturbative drift rates of each of the plurality of optical devices which are each exposed to the perturbation.