Bandgap Temperature Sensor for Photonic Integrated Circuit Thermal Stabilization
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Solution Overview
Problem
Photonic integrated circuits with semiconductor optical waveguides are vulnerable to thermal perturbations due to their high thermo-optic coefficients, leading to instability and wavelength drifts, which is detrimental for applications requiring precise temperature control.
Innovation Solution
Incorporating an integrated bandgap temperature sensor comprising two p/n junctions within the optical layer of the photonic integrated circuit, which produces an electrical signal indicative of temperature and is used to drive a temperature control element to stabilize the optical waveguide against thermal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If semiconductor materials with high refractive index are used in optical waveguides to enable tighter bends and smaller circuits, then the device size and integration density are improved, but the sensitivity to temperature variations worsens due to high thermo-optic coefficients
Solution Approach 1:
The patent implements a feedback control system where a temperature sensor continuously monitors the temperature of the semiconductor optical waveguide and feeds this information to a control element (such as a thermal actuator or tuning mechanism). This closed-loop feedback enables real-time compensation for temperature-induced refractive index changes, maintaining stable optical performance despite environmental temperature variations, thus resolving the contradiction between using high-index semiconductor materials and achieving temperature stability.
2Manufacturing precision
If semiconductor fabrication processes are used to create photonic integrated circuits, then manufacturing precision and integration capability are improved, but sensitivity to thermal perturbations worsens due to the inherent properties of semiconductor materials
Solution Approach 1:
The patent introduces a temperature sensor and control mechanism as an intermediary system between the semiconductor optical waveguide and the environment. This intermediary continuously measures the actual temperature of the waveguide and activates thermal compensation mechanisms to counteract thermal perturbations, thereby protecting the semiconductor-based photonic circuit from thermal sensitivity while preserving the benefits of semiconductor fabrication precision.
3Productivity
If micro-ring resonators are used for high-speed modulation and wavelength filtering, then functional performance is improved, but vulnerability to thermal perturbations worsens due to phase sensitivity and high thermo-optic coefficients
Solution Approach 1:
The patent applies feedback control specifically to micro-ring resonators by integrating temperature sensors that monitor the resonator temperature and control elements that adjust the refractive index or physical dimensions of the resonator. This feedback mechanism compensates for thermal drift in the resonant wavelength, enabling high-speed modulation and precise wavelength filtering to maintain stable operation across temperature variations, thus resolving the contradiction between functional performance and thermal stability.
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 solution effectively stabilizes the optical micro-ring resonator and allows for precise wavelength tuning, reducing the sensitivity to environmental temperature variations and ensuring stable operation across a wide temperature range.
Implementation Method 1
a temperature sensor based on dual p/n junctions and configured for producing an electrical signal that is indicative of a temperature of the PIC
Implementation Method 2
a temperature control element in thermal communication with the at least one optical waveguide, the temperature control element configured to adjust a temperature of the at least one optical waveguide
Data Source
AI summary
An optical device that includes means for thermal stabilization and control is described. The optical device can be a ring resonator, or another device that requires accurate control of the phase of the optical signal. In an example involving an optical resonator, a thermal stabilization system includes a temperature sensor, a control circuit, and a heater local to the resonator. The temperature sensor can be a bandgap temperature sensor formed of a pair of matched p/n junctions biased in operation at different junction currents.