MEMS Micro-Mirror Alignment for Laser-to-PIC Coupling Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional co-packaged laser assemblies in photonic integrated circuits face challenges such as post-cure shift, thermo-mechanical deformations, and difficulty in active alignment due to limited space, leading to coupling penalties and increased costs, especially in multi-channel systems.
Innovation Solution
Incorporation of an actuatable MEMS micro-mirror device between the laser and photonic integrated circuit (PIC) to compensate for misalignments, providing angular rotations and axial movements to maintain optimal coupling, using feedback mechanisms to adjust the laser beam alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a focusing lens is fixed in place by adhesive after active alignment, then the alignment is stabilized, but post-cure shift occurs causing coupling penalty
Solution Approach 1:
The patent replaces the mechanical adhesive-based focusing lens mounting with a magnetic coupling system. The magnetic coupling allows the focusing lens to be held in position without physical attachment, eliminating post-cure shift while maintaining alignment stability. The magnetic force provides sufficient holding strength without requiring adhesive curing that causes dimensional changes.
Solution Approach 2:
The patent introduces a movable focusing lens that can be dynamically adjusted during assembly and manufacturing. The magnetic coupling enables the lens to be repositioned if needed, providing dynamic adjustment capability rather than static fixed positioning. This allows for alignment optimization without being constrained by adhesive curing limitations.
2Ease of operation
If top side access is used for final active alignment of the focusing lens, then alignment can be performed, but space is limited in multi-channel systems
Solution Approach 1:
The patent moves the active alignment process from the top side (vertical dimension) to the bottom side (substrate level) of the module. By providing access to the focusing lens through the substrate, multi-channel systems can be configured in a planar arrangement without vertical interference, effectively utilizing the horizontal plane for multiple channels.
Solution Approach 2:
The patent divides the alignment access into separate channels, with each channel having its own dedicated access path through the substrate. This segmentation allows multiple channels to be independently aligned and configured without interfering with each other, enabling dense multi-channel integration while maintaining individual alignment capability.
3Ease of manufacture
If passive attachment is used for laser, lens arrangement, and PIC, then assembly is simplified, but alignment tolerance of 10 μm is insufficient for sub-micron optical coupling
Solution Approach 1:
The patent introduces a magnetic coupling intermediary between the focusing lens and the substrate. This magnetic intermediary provides the necessary precision for sub-micron alignment while maintaining the simplicity of passive attachment for the main components. The magnetic coupling acts as a precision positioning mechanism that bridges the gap between coarse passive alignment and fine optical coupling requirements.
Solution Approach 2:
The patent implements a feedback mechanism during the assembly process to guide the passive attachment components into precise alignment. By providing real-time alignment feedback, the system can achieve sub-micron coupling precision even with passive attachment methods, as the feedback enables iterative adjustment and optimization of component positions.
4Adaptability or versatility
If conventional co-packaged laser assemblies are used, then integration is achieved, but thermo-mechanical deformations from CTE mismatch cause coupling instability
Solution Approach 1:
The patent changes the physical parameters of the mounting system by using magnetic coupling instead of rigid mechanical attachment. This allows the focusing lens to accommodate thermo-mechanical deformations through magnetic field adjustments rather than rigid constraints. The magnetic coupling parameters can be adjusted to compensate for CTE mismatch and thermal expansion, maintaining coupling stability under varying thermal conditions.
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
The MEMS micro-mirror device effectively compensates for misalignments caused by thermo-mechanical forces and post-cure shifts, maintaining coupling efficiency over the life of the module and enabling scalable multi-channel configurations.
Implementation Method 1
the actuatable MEMS mirror is configured to reflect an incident laser beam to the fixed mirror and the fixed mirror is configured to reflect an incident laser beam into the waveguide
Implementation Method 2
The laser assembly comprises a thermal electric cooler (TEC) and a laser thermally coupled to the TEC
Data Source
AI summary
Disclosed is an opto-electronic module including a first substrate, a photonic integrated circuit (PIC) attached to the first substrate, a laser assembly attached to the first substrate, and a microelectromechanical systems (MEMS) micro-mirror device positioned between the laser and the waveguide. The PIC comprising a waveguide. The laser assembly is configured to generate a laser beam to optically couple to the waveguide. The laser assembly includes a thermal electric cooler (TEC) and a laser thermally coupled to the TEC. The MEMS micro-mirror device comprising an actuatable MEMS mirror and a fixed mirror.