Optical Module Radiation Light Extraction for Short Wavelength Monitoring
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Solution Overview
Problem
Commercially available fiber couplers are unreliable for visible light with short wavelengths due to photodarkening, leading to fluctuations in transmittance and refractive index, and using bulk components like beam splitters increases device size and introduces connection losses.
Innovation Solution
An optical module with a closed case body, fiber fixing portion, and light receiving element that uses a heat shrinkable tube to enhance light scattering and accurately measure radiation light intensity, reducing errors and allowing for downsized devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a fiber coupler is used to monitor light intensity, then the device size can be reduced, but the measurement reliability deteriorates due to photodarkening effects at short wavelengths
Solution Approach 1:
The optical fiber is divided into two separate paths: one for light propagation and another for radiation light extraction. The radiation light is extracted at a specific location and directed to a light receiving element, separating the measurement function from the light transmission path to avoid photodarkening effects
Solution Approach 2:
A radiation light extracting portion is introduced as an intermediary element between the optical fiber and the light receiving element. This intermediary extracts radiation light from the optical fiber without requiring the light to pass through a fiber coupler, thereby avoiding photodarkening while maintaining compact dimensions
2Reliability
If a beam splitter is used instead of a fiber coupler, then measurement reliability improves, but the device size increases and connection losses occur
Solution Approach 1:
The light receiving element is nested within a case body that forms a closed space containing the radiation light extracting portion. This nested structure integrates multiple functions (light extraction, light reception, and structural support) into a compact module, achieving reliable measurement without increasing overall device size
3Reliability
If a beam splitter is used, then measurement reliability improves, but connection loss increases due to light recombination errors
Solution Approach 1:
The radiation light is extracted directly from the optical fiber at a specific location using the radiation light extracting portion, bypassing the need for beam splitting and recombination. This extraction approach eliminates connection losses associated with beam splitter recombination while maintaining measurement 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
Accurately observes the intensity of visible light with short wavelengths through optical fibers, reducing errors from photodarkening and enabling device miniaturization while maintaining reliable light measurement.
Implementation Method 1
uses a heat shrinkable tube to enhance light scattering
Data Source
AI summary
Provided is an optical module that accurately observes the overall intensity of visible light having a relatively short wavelength and propagating through an optical fiber, and is suitable for downsizing an optical device. An optical module provided in an optical fiber connected to an optical component capable of inputting or outputting light. The optical module includes: a case body that forms a closed space C in which a part of the optical fiber is accommodated; a fiber fixing portion that fixes the optical fiber to predetermined position and shape inside the case body; and a photodiode that is attached inside the case body at a position capable of receiving radiation light radiated from the optical fiber fixed to the fiber fixing portion.