Optical Circuit Reflected Light Reduction via Coupler Ratio
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Solution Overview
Problem
Existing optical circuits face increased costs and optical loss due to the need for optical isolators to mitigate the effect of reflected light, which can destabilize light sources in optical communication systems.
Innovation Solution
An optical circuit design featuring a first optical coupler with a lower reflected-light intensity ratio than a second optical coupler, where the optical couplers are coupled via an optical waveguide, and the ratio of reflected light intensity to input light intensity in the second coupler is minimized to reduce the impact of reflected light on the light source, while maintaining acceptable optical loss and manufacturing tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical isolator is placed outside the optical integrated circuit chip to prevent reflected light from destabilizing the light source, then the stability of the light source is improved, but the cost and device complexity increase
Solution Approach 1:
The patent extracts the light source from the integrated circuit chip and places it outside, connected via optical waveguides. This separation allows the light source to be isolated from reflected light generated within the chip, eliminating the need for an optical isolator while maintaining light source stability. The extraction principle resolves the contradiction by removing the harmful interaction between reflected light and the light source through spatial separation.
Solution Approach 2:
The patent introduces optical waveguides as intermediary elements to connect the external light source with the integrated circuit chip. These waveguides serve as mediators that transmit light while preventing reflected light from the chip from returning to the light source, thus protecting the light source stability without requiring an optical isolator. The intermediary waveguides resolve the contradiction by providing a transmission path that blocks the harmful feedback loop.
2Reliability
If the optical coupler is designed to minimize reflected light intensity ratio, then the stability of the light source is improved, but the optical loss increases
Solution Approach 1:
The patent applies different design optimizations to different components: the optical coupler is optimized for low reflected light intensity ratio to protect the light source, while the overall system accepts higher optical loss in other components. This local optimization approach allows the critical light source stability to be improved without requiring all components to be optimized, thus resolving the contradiction between reflected light reduction and optical loss.
3Device complexity
If the optical circuit is designed without an optical isolator to reduce cost, then the device complexity is reduced, but the light source becomes unstable due to reflected light
Solution Approach 1:
The patent segments the optical system into distinct functional modules: an external light source, optical waveguides, and an integrated circuit chip with optical couplers. This segmentation physically separates the light source from the chip, breaking the feedback loop that causes instability from reflected light. By dividing the system into separate components, the patent eliminates the need for an optical isolator while maintaining light source stability, thus resolving the contradiction between device complexity and 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 design effectively reduces the effect of reflected light on the light source, avoiding increased optical loss and manufacturing deviations, thus stabilizing the optical circuit operation at a lower cost without the need for expensive isolators.
Implementation Method 1
a ratio of intensity of light reflected from the first optical coupler to intensity of light inputted to the first optical coupler
Implementation Method 2
the first optical coupler and the second optical coupler are coupled via an optical waveguide
Data Source
AI summary
A low-cost optical circuit, in which influence of reflected light is reduced, is provided. According to an embodiment of the present invention, an optical circuit (200) comprises a first optical coupler (204A) having at least two outputs, and a second optical coupler (204B) coupled to at least one of the outputs of the first optical coupler (204A), and wherein the ratio of an intensity of light reflected from the first optical coupler (204A) to an intensity of light inputted to the first optical coupler is smaller than the ratio of an intensity of light reflected from the second optical coupler (204B) to an intensity of light inputted to the second optical coupler.