Undercut MRR Base Cover for Thermal Isolation and Tuning
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Solution Overview
Problem
Existing silicon photonics micro-ring resonators in open-cavity photonic integrated circuits face challenges in thermal isolation and temperature control due to inefficient thermal management and inaccurate temperature sensing, which affects wavelength division multiplexing systems.
Innovation Solution
A backside etching process is employed to create cavities through the silicon substrate, buried oxide, and cladding layers, coupled with a metallic temperature sensor placed close to the micro-ring to accurately measure its temperature, and a bump and MRR layout that enhances thermal isolation without increasing footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If channels are formed around the MRR to improve thermal isolation, then thermal cross-talk is reduced, but the device complexity increases
Solution Approach 1:
The patent transitions from planar thermal isolation (channels around MRR) to three-dimensional thermal management by etching cavities through the substrate beneath the MRR. This vertical cavity structure provides superior thermal isolation without increasing the lateral footprint or device complexity, as the isolation occurs in the depth dimension rather than requiring additional lateral channels.
2Measurement precision
If existing temperature sensors are used separated from the MRR by cladding, then the sensor structure is simple, but the temperature measurement accuracy deteriorates
Solution Approach 1:
The patent introduces a thermal conductor as an intermediary material filling the cavity between the MRR and the temperature sensor. This thermal conductor bridges the thermal gap created by the cladding, enabling accurate temperature measurement by conducting heat from the MRR to the sensor without requiring direct contact or complex sensor integration.
3Ease of manufacture
If the integrated heater is formed in the center of the micro-ring, then fabrication costs are minimized, but thermal isolation becomes insufficient
Solution Approach 1:
The patent segments the thermal management function by separating the heating function (integrated heater in MRR center) from the thermal dissipation function (cavity structure). The heater remains centrally located for simple fabrication, while the cavity etched through the substrate provides thermal isolation by creating an air gap that prevents heat from conducting to the substrate, thus eliminating thermal cross-talk without complicating the heater fabrication.
4Object-affected harmful factors
If backside etching is used to create cavities, then thermal isolation is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent inverts the conventional top-down fabrication approach by implementing backside etching to create cavities from the substrate underside. This allows the cavity formation to occur independently of the MRR and sensor fabrication steps, enabling thermal isolation to be added without disrupting existing manufacturing flows. The inverted approach simplifies integration by separating the thermal management structure creation from the device layer processing.
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 improves thermal isolation and temperature control of micro-ring resonators, enabling stable temperature maintenance and efficient thermal tuning, reducing thermal cross-talk and enhancing the reliability of wavelength division multiplexing systems.
Implementation Method 1
A heater is normally integrated into the MRR to enable wavelength resonance tuning. Applying heat shifts the resonance frequency of the MRR.
Implementation Method 2
channels are formed around the MRR in order to improve thermal isolation. This allows for high temperatures to be reached, and limits thermal cross-talk.
Implementation Method 3
the existing temperature sensors are separated from the MRR by a cladding that does not have good thermal conductivity
Data Source
AI summary
Embodiments disclosed herein include optoelectronic systems and methods of forming such systems. In an embodiment, an optoelectronic system comprises a first substrate, a second substrate over the first substrate, a micro-ring resonator (MRR) over the second substrate, a heater integrated into the MRR, a cladding over the MRR, an opening through the first substrate and the second substrate to expose a bottom surface of the MRR, and a base spanning across the opening.