Beam Redirector for Laser-to-PIC Coupling Alignment
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Solution Overview
Problem
Existing silicon photonics technologies face challenges in efficiently integrating and aligning III-V laser sources with photonic integrated circuits, particularly due to sensitive grating couplers that require precise alignment and are affected by variations in wavelength, angle of incidence, and polarization.
Innovation Solution
The implementation of an optical assembly with a beam redirector, comprising a cylindrical portion and a reflector portion, allows for active fine-tuning of the light beam onto the grating coupler through longitudinal and rotational movements, optimizing the angle of incidence and focal point alignment for improved coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If grating couplers are used for coupling laser to photonic integrated circuit, then coupling efficiency can be improved, but alignment precision requirements increase and manufacturing complexity increases
Solution Approach 1:
A beam redirector component is introduced as an intermediary element between the laser source and the grating coupler. This beam redirector includes a cylindrical portion and a reflector portion that work together to redirect and focus the laser beam onto the grating coupler, serving as a mediator that simplifies the overall alignment process while maintaining high coupling efficiency
Solution Approach 2:
The beam redirector is designed with movable components that allow dynamic adjustment of the beam path. The reflector portion can be positioned at different angles and the cylindrical portion can be rotated, enabling active fine-tuning of the beam orientation to achieve optimal alignment with the grating coupler without requiring extremely tight manufacturing tolerances
2Loss of energy
If grating couplers are used for coupling laser to photonic integrated circuit, then coupling efficiency can be improved, but device complexity increases
Solution Approach 1:
The beam redirector combines multiple optical functions into a single integrated component. The cylindrical portion and reflector portion are merged into one assembly that simultaneously performs beam focusing, beam redirecting, and alignment functions, reducing the number of separate components needed in the overall laser-to-PIC coupling system
Solution Approach 2:
The beam redirector serves multiple functions: it acts as a beam splitter, a focusing element, an alignment mechanism, and a positioning device all in one component. This multi-functionality reduces the overall device complexity by eliminating the need for separate optical elements for each function
3Ease of manufacture
If fixed alignment is used for laser coupling, then manufacturing is simpler, but coupling efficiency decreases due to sensitivity to wavelength and angle variations
Solution Approach 1:
The beam redirector incorporates movable components including a rotatable cylindrical portion and an adjustable reflector portion that can be dynamically positioned to optimize the beam angle and focal point. This dynamic adjustability allows the system to compensate for variations in laser wavelength and manufacturing tolerances, maintaining high coupling efficiency without requiring complex fixed precision alignment mechanisms
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 enables a more efficient and cost-effective integration of III-V laser sources with silicon photonics, reducing coupling losses and improving polarization alignment, while allowing for wider tolerances in manufacturing and easier wafer-level testing.
Implementation Method 1
a beam redirector configured to redirect the light from the coupling lens system onto the grating coupler
Implementation Method 2
allows for active fine-tuning of the light beam onto the grating coupler through longitudinal and rotational movements, optimizing the angle of incidence and focal point alignment
Implementation Method 3
a grating coupler configured to receive the light from the beam redirector and couple the light into a waveguide
Data Source
Figure 1A~1B
Figure 2
Figure 3A
AI summary
A photonic integrated circuit for coupling a laser from an optical assembly to a grating coupler is disclosed. A method for coupling a laser to a photonic integrated circuit is disclosed. The optical assembly includes an optical system disposed on a v-groove bench. The optical system typically includes a laser source, a coupling lens or lens system, an optional isolator, a beam redirector that includes a prism or other light turning element and a cylindrical tube mounted on the v-groove bench. The method of tuning the angle of incidence from the optical assembly to the grating coupler is also disclosed.