Mode-Dependent Loss Measurement Using Direct Core Detection
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Solution Overview
Problem
Existing mode-dependent loss measurement techniques for multi-core optical devices are limited by the inclusion of mode-dependent loss from both the light input and output members, which reduces the reliability of the measurements.
Innovation Solution
A mode-dependent loss measurement apparatus that includes M optical waveguides, an optical element to transmit and reflect light, a modulation unit to individually modulate light beams, optical detectors to receive signals, and a processing unit to calculate mode-dependent loss without the need for fan-in and fan-out devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional measurement methods using fan-in and fan-out devices are employed, then the measurement can be performed with simpler setup, but the mode-dependent loss of both light input and output members is included in the measurement results, reducing measurement reliability
Solution Approach 1:
The invention extracts and eliminates the light output member from the measurement system. By using only a light input member to couple probe light into the multi-core optical device and directly detecting the emitted light, the measurement system excludes the mode-dependent loss contribution from the output member, thereby improving measurement reliability without requiring complex fan-in and fan-out devices
Solution Approach 2:
The light input member serves multiple functions: it acts as both the coupling device for probe light and the reference standard for mode-dependent loss measurement. This multi-functionality eliminates the need for separate fan-in and fan-out devices, reducing system complexity while maintaining measurement reliability
2Measurement precision
If fan-in and fan-out devices are used to couple and guide light, then the measurement setup is more complete, but the mode-dependent loss measurements include contributions from both input and output members, reducing accuracy
Solution Approach 1:
The invention removes the fan-out device and light output member from the measurement system. The probe light is coupled into the multi-core optical device through the fan-in device, and the light emitted from each core is directly detected without passing through an output member, thereby eliminating the mode-dependent loss contribution from output components and improving measurement accuracy
Solution Approach 2:
Instead of measuring light that passes through both input and output members (traditional approach), the invention inverts the measurement approach by directly detecting the light emitted from each core of the multi-core optical device. This inversion eliminates the confounding factor of output member losses and improves measurement precision
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 reliable mode-dependent loss measurements by excluding the mode-dependent loss of the light output member, thereby improving measurement accuracy and reliability compared to traditional methods.
Implementation Method 1
an optical element configured to transmit a partial amount of first light guided through the M cores of the target object and a partial amount of second light guided through the M optical waveguides, and to reflect remaining amount thereof
Implementation Method 2
an optical system configured to guide the first light and the second light such that the plurality of beams of the first light and a plurality of beams of the second light overlap in pairs on the first optical detector and the second optical detector
Data Source
AI summary
An apparatus includes an element to transmit a partial amount of first light guided through the M cores of a target object and second light guided through M optical waveguides, and to reflect remaining amount thereof, a first modulator to individually modulate the first light, a first detector to output a first signal based on the first light reflected by the element and the second light passing through the element, a second detector to output a second signal based on the first light passing through the element and the second light reflected by the element, an optical system configured such that the first light and the second light overlap in pairs on the first and second detectors, and a processing unit configured to output information about mode-dependent loss of the target object based on the first signal, the second signal, and information about modulation given by the first modulator.