Optical Transmitter With Multimode Fiber for Low-Noise Transmission
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Solution Overview
Problem
Conventional optical transmission systems face challenges in achieving stable, high-quality signal transmission with reduced noise, particularly in systems transmitting radio frequency signals, due to the use of optical isolators which increase size and cost while reducing return light to the laser side.
Innovation Solution
An optical transmitter and transmission system utilizing a multimode optical fiber optically coupled to a lens, with a correlation coefficient between light intensity distribution and return light intensity distribution set to 0.5 or less, to reduce return light and noise without an optical isolator, enhancing mode coupling through microbending and light scattering in the fiber core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical isolator is used to reduce return light to the laser side, then signal quality is improved, but device size and cost increase
Solution Approach 1:
The patent extracts and eliminates the optical isolator component from the system by using a multimode optical fiber that inherently prevents return light from reaching the laser, thereby reducing device size and complexity while maintaining signal quality
Solution Approach 2:
The multimode optical fiber acts as an intermediary element between the laser and the optical network, utilizing its modal dispersion properties to prevent return light from coupling back to the laser, thus eliminating the need for an optical isolator
2Reliability
If an optical isolator is used to reduce return light to the laser side, then signal quality is improved, but system cost increases
Solution Approach 1:
The patent removes the expensive optical isolator component from the system by leveraging the inherent properties of multimode optical fiber to prevent return light, thereby reducing system cost while maintaining signal quality
Solution Approach 2:
The patent uses standard multimode optical fiber, which is a cost-effective and widely available component, replacing the expensive optical isolator to achieve the same return light suppression function at lower cost
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 configuration achieves a reduction in size and cost while improving signal quality by minimizing noise, particularly in systems susceptible to radio frequency interference, without the need for optical isolators.
Implementation Method 1
a lens that condenses the light emitted from the light emitting part
Implementation Method 2
a multimode optical fiber that is optically coupled to the lens at one end and on which the light that is condensed by the lens is incident
Implementation Method 3
enhancing mode coupling through microbending and light scattering in the fiber core
Data Source
AI summary
An optical transmitter includes: a light emitting part that emits light; and a lens that condenses the light emitted from the light emitting part. Further, the optical transmitter includes a multimode optical fiber that is optically coupled to the lens at one end and on which the light that is condensed by the lens is incident. Furthermore, the coefficient of the correlation between the distribution of the intensity of the light in the light emitting part and the distribution of the intensity of return light to the light emitting part, when the light is emitted from the light emitting part, is set to 0.5 or less.