Wafer-Level Optical Switch with Loop Mirror for Return Light Measurement
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Solution Overview
Problem
Conventional optical chip testing methods require alignment of optical axes for each chip, increasing measurement workload and making it difficult to achieve high accuracy in measuring reflected return light.
Innovation Solution
An optical device is formed on a wafer with an optical circuit, grating coupler, and optical switch. The optical switch includes a first port connected to the grating coupler, a second port connected to the optical circuit, and a third port connected to a loop mirror via a phase shifter, allowing for accurate cancellation of reflected light and improved measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alignment work is performed for each optical chip after cutting from wafer, then measurement of reflected return light can be conducted, but work load increases and measurement efficiency decreases
Solution Approach 1:
The patent performs alignment work on the wafer before cutting the optical chips. By pre-aligning the optical axes of the optical ports with the optical fiber in the wafer state, all chips inherit the same alignment configuration. This preliminary action eliminates the need for repetitive alignment work after cutting, significantly improving measurement efficiency while maintaining measurement accuracy.
2Productivity
If test is carried out in wafer state before chipping, then work efficiency increases, but alignment complexity and device complexity increase
Solution Approach 1:
The patent combines multiple optical chips on a single wafer and performs alignment work collectively for all chips simultaneously. By merging the alignment operations that would otherwise be performed individually on each chip, the system reduces overall alignment complexity while improving work efficiency. The optical fiber is aligned once to serve multiple optical ports on the wafer.
3Reliability
If conventional test method is used with individual chip measurement, then each chip can be tested independently, but measurement workload and time consumption increase
Solution Approach 1:
The patent performs preliminary alignment work on the wafer before cutting the chips. This preliminary action ensures that when individual chips are tested later, the alignment is already established, eliminating the need for time-consuming alignment procedures during each individual chip measurement. This significantly reduces measurement time while maintaining testing reliability.
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 high-accuracy measurement of reflected return light from the optical circuit, reducing measurement workload and improving testing efficiency by allowing tests to be performed in the wafer state before chip separation.
Implementation Method 1
a third port that is connected to a loop mirror by way of a phase shifter
Implementation Method 2
a grating coupler, and an optical switch. The optical switch includes a first port that is connected to the grating coupler
Data Source
AI summary
An optical device is an optical device that is formed on a wafer. The optical device includes an optical circuit, a grating coupler, and an optical switch that includes a first port that is connected to the grating coupler, a second port that is connected to the optical circuit, and a third port that is connected to a loop mirror by way of a phase shifter.