Thermally Compensated Arrayed Waveguide Grating with Folded Paths
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Solution Overview
Problem
Existing arrayed waveguide gratings (AWGs) face challenges in maintaining signal integrity due to temperature changes, which cause shifts in the center wavelength and affect the performance of optical circuits, leading to inefficiencies in multiplexing and de-multiplexing functions.
Innovation Solution
The implementation of a thermally compensated AWG design that incorporates a pivotable mirror and actuator system, allowing for adjustments in the optical path to maintain signal integrity across temperature changes, while also reducing the physical size of the AWG through folded optical paths and efficient placement of access waveguides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional AWG design is used, then the device structure is simple, but the device footprint is large and cannot be effectively temperature compensated
Solution Approach 1:
The patent employs a pivotable mirror that can dynamically adjust its angle in response to temperature changes. The mirror assembly includes an actuator that pivots the mirror about an axis, allowing the optical path to be dynamically reconfigured to compensate for thermal effects on the AWG performance
Solution Approach 2:
The patent changes the reflection angle parameter of the mirror to compensate for temperature-induced wavelength shifts. By adjusting the mirror angle, the optical path length through the AWG is modified, thereby compensating for thermal effects and maintaining center wavelength stability
2Area of stationary object
If direct optical connection is used, then the device structure is simple, but the device footprint is large
Solution Approach 1:
The patent uses a folded optical path configuration where the optical path is bent back on itself using mirrors, effectively utilizing three-dimensional space rather than requiring a large two-dimensional footprint. This allows the optical path to be compacted while maintaining the necessary optical path length
Solution Approach 2:
The pivotable mirror assembly allows the optical path to be dynamically reconfigured, enabling compact packaging while maintaining proper optical alignment. The mirror can pivot to adjust the optical path geometry, facilitating a compact design that adapts to space constraints
3Reliability
If mirror assembly with actuator is added, then temperature compensation is achieved, but device complexity increases
Solution Approach 1:
The mirror assembly is designed to automatically respond to temperature changes through its actuator mechanism, providing self-compensation without requiring external control systems. The actuator pivots the mirror in response to thermal expansion or contraction of the mounting structure, enabling automatic temperature compensation
Solution Approach 2:
The patent utilizes thermal expansion of the mirror assembly mounting structure to drive the compensation mechanism. As temperature changes, the differential thermal expansion between different materials causes the mirror to pivot, automatically adjusting the optical path to compensate for AWG wavelength shifts
4Area of stationary object
If compact design with folded paths is used, then device footprint is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The pivotable mirror assembly provides a mechanism for fine-tuning the optical path alignment. By adjusting the mirror angle, manufacturing misalignments can be compensated, providing a feedback mechanism that corrects for tolerances in the fabrication process
Solution Approach 2:
The dynamic adjustment capability of the pivotable mirror allows for post-fabrication alignment tuning. The mirror can be pivoted to correct alignment errors introduced during manufacturing, reducing the stringency of precision requirements during the fabrication process
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 design provides a compact, cost-effective, and temperature-independent AWG that maintains signal integrity and reduces the footprint of the device, enabling more efficient multiplexing and de-multiplexing functions, allowing for a larger number of devices on a substrate with reduced manufacturing costs.
Implementation Method 1
an optical path through the first slab waveguide from the access edge is folded by providing an optical reflection from a mirror
Implementation Method 2
the mirror assembly comprises an actuator that pivots the mirror along a rotation in the plane of the slab waveguide in response to a change in temperature
Data Source
AI summary
Arrayed waveguide grating can have one or both slab waveguides with relatively sharply folded optical paths and a mirror that provides the folding of the path. The folded optical paths through the slab waveguides can result in a more compact geometry of the waveguides through the device as well as smaller slab waveguides such that the device can be formed with a significantly smaller overall footprint. Also, arrayed waveguide gratings that cooperate with pivotable mirrors can adjust light passage through the waveguide in response to temperature changes to provide for thermally compensated operation of the device. Thus, very compact planar lightwave circuits filters are described that provide thermally compensated operation.