Tunable Waveguide Devices With Undercut Thermal Isolation
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Solution Overview
Problem
Existing tunable laser devices face inefficiencies in thermal tuning due to heat distribution issues, which affect the stability and precision of wavelength adjustment, especially when multiple lasers are integrated on a common substrate, leading to suboptimal thermal isolation and increased power consumption.
Innovation Solution
The implementation of a tunable waveguide device with an undercut region below the grating-based reflector or phase section to thermally isolate the tunable section from the substrate and other components, combined with heaters having tapered ends to enhance heat dissipation and efficiency, allowing for more precise wavelength control across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If heaters are used for thermal tuning of wavelength, then wavelength adjustment capability is improved, but power consumption increases and thermal isolation deteriorates
Solution Approach 1:
The device is segmented into distinct functional regions: a gain section, a phase section with heaters for wavelength tuning, and an undercut region for thermal isolation. This segmentation allows the heaters to be applied only where needed for wavelength adjustment without heating the entire device, thereby reducing overall power consumption while maintaining wavelength tuning capability.
Solution Approach 2:
The undercut region extracts or removes the substrate material beneath the phase section, creating a suspended structure. This extraction provides thermal isolation that prevents heat from the heaters from dissipating into the substrate, thereby improving thermal tuning efficiency and reducing the power required for wavelength adjustment.
2Productivity
If multiple lasers are integrated on a common substrate, then device integration is improved, but thermal isolation between lasers deteriorates
Solution Approach 1:
Each laser device is segmented with its own undercut region, creating thermally isolated compartments on the common substrate. This allows multiple lasers to be integrated closely together while maintaining thermal isolation between them, as the undercut regions prevent heat from spreading to adjacent laser structures.
Solution Approach 2:
The undercut region acts as an intermediary thermal barrier between adjacent laser devices on the common substrate. By removing the substrate material in these regions, heat from one laser cannot easily transfer to neighboring lasers, thereby maintaining thermal isolation while enabling high device integration.
3Ease of manufacture
If heaters are placed on the substrate, then manufacturing simplicity is improved, but thermal isolation and tuning precision deteriorate
Solution Approach 1:
Instead of placing heaters only on the substrate surface, the heaters are positioned in a third dimension - suspended above the substrate in the phase section region. This dimensional change allows the heaters to be thermally isolated from the substrate while still being manufacturable using standard semiconductor fabrication techniques such as sacrificial layer deposition and etching.
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 enables more efficient thermal tuning, reduces power consumption, and improves mechanical and electrical stability, allowing for continuous and discrete wavelength adjustments across the C-Band and L-Band ranges with enhanced reliability and compact design.
Implementation Method 1
a heater may be used to change a characteristic of an optical device. For example, an operating wavelength of a semiconductor laser may be tuned by applying heat using a heater
Implementation Method 2
US2010/0311195 discloses a distributed Bragg reflector with improved thermal tuning efficiency
Implementation Method 3
an undercut region below the grating-based reflector or phase section to thermally isolate the tunable section from the substrate
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
Methods, systems, and apparatus, including a laser including a layer having first and second regions, the first region including a void; a mirror section provided on the layer, the mirror section including a waveguide core, at least part of the waveguide core is provided over at least a portion of the void; a first grating provided on the waveguide core; a first cladding layer provided between the layer and the waveguide core and supported by the second region of the layer; a second cladding layer provided on the waveguide core; and a heat source configured to change a temperature of at least one of the waveguide core and the grating, where an optical mode propagating in the waveguide core of the mirror section does not incur substantial loss due to interaction with portions of the mirror section above and below the waveguide core.