Pedestal-Aligned Waveguide Assembly for Low-Loss PIC Coupling
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Solution Overview
Problem
Current methods for coupling fibers to photonic integrated circuits (PICs) are time-consuming and costly, with active alignment techniques requiring expensive equipment and passive techniques leading to larger coupling losses.
Innovation Solution
An assembly and method for integrating micro-optical devices using pedestals and shoulders on a substrate to achieve precise vertical and horizontal alignment of waveguides, allowing easy and accurate positioning of PICs and fiber arrays without the need for active alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If active alignment techniques are used to couple fibers to PICs, then coupling precision is improved, but manufacturing cost and time consumption increase
Solution Approach 1:
The patent implements preliminary action by pre-aligning waveguides on the substrate using pedestals and shoulders before PIC assembly. The pedestals provide pre-defined vertical positioning and the shoulders provide pre-defined lateral positioning, so that when the PIC is placed on the substrate, the waveguides are already in the correct position for coupling, eliminating the need for time-consuming active alignment during final assembly
Solution Approach 2:
The patent introduces pedestals and shoulders as intermediary structures between the substrate and the PIC. These intermediaries serve as alignment references that mediate the positioning process, allowing the PIC to be passively aligned to the waveguides through mechanical contact with the pedestals and shoulders, rather than requiring active alignment equipment
2Productivity
If passive alignment techniques are used to couple fibers to PICs, then assembly time is reduced, but coupling losses increase
Solution Approach 1:
The waveguides are pre-positioned on the substrate using pedestals for vertical alignment and shoulders for lateral alignment before the PIC is assembled. This preliminary positioning ensures that when the PIC is placed on the substrate, the coupling interfaces are already aligned within acceptable tolerances, enabling passive alignment to achieve low coupling losses without requiring active alignment equipment
Solution Approach 2:
The patent replaces complex optical active alignment systems with simple mechanical structures (pedestals and shoulders) that provide passive alignment through physical contact and geometric constraints, achieving both simplicity and precision
3Manufacturing precision
If active alignment equipment is used, then alignment accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The pedestals and shoulders serve as intermediary alignment references that are integrated into the substrate fabrication process using standard semiconductor manufacturing techniques. These intermediaries provide precise alignment references without requiring expensive active alignment equipment, thereby reducing manufacturing costs while maintaining high alignment accuracy
Solution Approach 2:
The alignment references (pedestals and shoulders) are created as copies or replicas of the waveguide positions during substrate fabrication. By creating these reference structures in advance using precise lithography and etching processes, the system captures the alignment information in the substrate itself, eliminating the need for expensive external alignment equipment during assembly
Data Source
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AI summary
The subject matter of the present disclosure is directed to an assembly (100) for integrating a micro-optical device (10), comprising a waveguide (WG) chip and a substrate. The waveguide chip (20) has opposing first and second facets (22a, 22b) and at least one second waveguide (21) disposed therein between the first and second facets (22a, 22b). The second waveguide (21) is arranged between a first cladding (23) and a second cladding (24), wherein the first cladding (23) and the at least one second waveguide (21) have a common flat surface (25). The second cladding (24) may only cover a part of the common flat surface (25) such that the first cladding (23) comprises at least one free surface part (26a) beside the second cladding (24) which is free from the second cladding (23). The substrate (30) comprises a substrate base (31) and at least one first pedestal (32) being vertically arranged between the substrate base (31) and the at least one waveguide chip. The at least one first pedestal (32) is configured to vertically align the butt-coupling between the second waveguide (21) of the waveguide chip with a first waveguide (11) of a micro-optical device (10). At least one, preferably each, of the at least one free surface part (26a) of the first cladding (23) may contact a respective first pedestal (32).