Gain Chip Batch Characterization Using Reflective Diffraction Grating
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Solution Overview
Problem
Existing methods for characterizing gain chips are insufficient for predicting long-term behavior and may lead to the use of non-optimal chips in challenging environments, as they rely on nominal macroscopic parameters that can differ from real values, and sampling inspections are costly and time-consuming.
Innovation Solution
A method and system for characterizing a batch of gain chips by measuring differential quantum efficiency, modal gain coefficient, and carrier density at transparency using a reflective diffraction grating that changes angular positions to simulate lasing and amplified spontaneous emission conditions, allowing for rapid and reliable selection of optimal chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple discrete measurement steps are performed to characterise gain chips (measurements at different frequencies and conditions), then measurement precision is improved, but measurement time increases
Solution Approach 1:
The patent applies preliminary action by performing measurements at multiple frequencies and conditions in advance during the characterisation phase. This preliminary data collection enables the creation of comprehensive lookup tables that can be quickly queried during runtime, avoiding the need to perform time-consuming measurements during actual signal processing operations.
Solution Approach 2:
The patent creates simplified copies of the complex gain chip characteristics by generating lookup tables that store pre-measured data. These lookup tables serve as simplified representations that can be quickly searched and interpolated during runtime, replacing the need for complex real-time measurements while maintaining measurement precision.
2Measurement precision
If comprehensive measurements are performed on all gain chips in a batch, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the batch of gain chips into smaller groups or individual units that can be measured separately. By processing chips in manageable segments rather than attempting to measure all chips simultaneously as a single complex system, the measurement apparatus complexity is reduced while still achieving comprehensive batch characterisation through aggregated results.
3Manufacturing precision
If detailed characterisation data is collected for all chips, then manufacturing precision is improved, but loss of information increases due to data management complexity
Solution Approach 1:
The patent creates simplified data structures and lookup tables that capture the essential characterisation information needed for matching gain chips. By transforming complex measurement data into compact, structured formats with clear relationships, the system maintains manufacturing precision while reducing data management complexity and preventing information loss.
Data Source
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AI summary
Method for characterizing a batch of gain chips, each having a first reflective face and a second transparent face, the method comprising, for each gain chip: positioning the gain chip (99) with the second face facing towards a reflective diffraction grating (6); supplying the gain chip (99) with a plurality of first and second values of supply current so that the gain chip (99) emits a respective first light beam (60) for each first value of supply current and a respective second light beam (60') for each second value of supply current; making impinge each first light beam (60) on the reflective diffraction grating (6) in a first angular position so as to generate a respective first zero-order diffracted beam (61) and a respective first first-order diffracted beam (62) entering the gain chip (99), and each second light beam (60') on the reflective diffraction grating (6) in a second angular position so as to generate a respective second zero-order diffracted beam (63) and a respective second first-order diffracted beam (64) not entering the gain chip (99); measuring a respective first value of optical power of each first zero-order diffracted beam (61), and a respective second value of optical power of each second zero-order diffracted beam (63); associating each first value of optical power with the respective first value of supply current, and each second value of optical power with the respective second value of supply current; as a function of pairs of first values of supply current and of optical power and as a function of a first predetermined mathematical correlation, calculating a respective differential quantum efficiency, and, as a function of pairs of second values of supply current and of optical power and as a function of a second predetermined mathematical correlation, calculating a respective modal gain coefficient and a respective carrier density at transparency; verifying that the respective differential quantum efficiency, the respective modal gain coefficient, and the respective carrier density at transparency satisfy a respective predetermined selection criterion.