Optical Multiplexer Using Polarization State Adjustment
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Solution Overview
Problem
Existing optical multiplexers have large volumes, significant differences in output optical power and energy distribution between channels, and high insertion loss when coupling with fibers, leading to increased power consumption and reliability issues.
Innovation Solution
The design employs polarization multiplexing to adjust and combine optical signals, reducing the number of reflections and resulting in a compact form with minimal insertion loss by utilizing polarization state adjusting components, polarization beam combiners, and optical path changing components to align and combine optical signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a Zig-Zag TFF-based optical MUX device is used to combine light from multiple TOSAs, then the optical signals can be multiplexed, but the volume of the device becomes too large for integration
Solution Approach 1:
The patent merges multiple optical paths into a single integrated waveguide structure. The PLC-based multiplexer integrates multiple input waveguides and output waveguides with coupling regions where evanescent field coupling occurs, combining multiple optical signals into one without requiring separate reflection components for each channel. This integration dramatically reduces the device volume compared to traditional Zig-Zag TFF approaches.
Solution Approach 2:
The patent replaces mechanical reflection-based optical path switching (using mirrors and filters) with an optical field-based coupling mechanism. The evanescent field coupling in the PLC waveguide structure substitutes for mechanical reflection and redirection, eliminating the need for bulky optical components while achieving the same signal combination function.
2Adaptability or versatility
If traditional optical MUX device designs are used, then optical signals can be combined, but laser light in different channels is reflected for different numbers of times, causing significant difference in output optical power and optical field energy distribution
Solution Approach 1:
The patent creates equipotential optical paths by designing all input waveguides to have identical coupling conditions with the central waveguide. Each input channel experiences the same number of coupling interactions and similar propagation distances, ensuring that optical power and field energy distribution are uniform across all channels. This eliminates the unequal reflection and path length issues of traditional designs.
3Adaptability or versatility
If conventional optical MUX devices with multiple reflections are used, then optical signals can be multiplexed, but great insertion loss exists in coupling between the MUX device and laser and fiber
Solution Approach 1:
The patent replaces mechanical reflection-based coupling with evanescent field coupling between adjacent waveguides. This optical field interaction occurs continuously along the coupling region without discrete reflection events, minimizing insertion loss. The direct field coupling between input and output waveguides eliminates the multiple reflection interfaces that cause energy loss in conventional devices.
Solution Approach 2:
The patent implements continuous optical field coupling along the length of the waveguide interaction region. Instead of discrete reflection events, the evanescent fields continuously transfer energy from input waveguides to the central waveguide, maintaining efficient energy transfer throughout the coupling process and reducing overall insertion loss.
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 approach results in a smaller, more efficient optical multiplexer with consistent optical field energy distribution and reduced insertion loss when coupled with fibers, improving power management and system reliability.
Implementation Method 1
The optical multiplexer provided in the embodiments of the present invention use the polarization feature of laser light to change the polarization state of a part of multiple optical signals to be multiplexed, and then combine any one optical signal in the changed polarization state and any one optical signal in the unchanged polarization state into one optical signal through polarization multiplexing
Implementation Method 2
reflected and combined by a filter and a reflector for multiple times
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2D
AI summary
The present invention relates to the optical communication field and discloses an optical signal multiplexing method and an optical multiplexer to multiplex at least four optical signals into one optical signal. The method provided in the present invention includes: adjusting polarization states of two of four optical signals to be multiplexed, so that the polarization states of the two adjusted optical signals are different from, and preferably, mutually orthogonal to, the polarization states of the remaining two optical signals; combining one optical signal in the adjusted polarization state with one optical signal in the unadjusted polarization state into one optical signal through polarization multiplexing; and combining the two optical signals obtained through polarization multiplexing into one optical signal, so that the four optical signals are multiplexed into one optical signal. When multiplexing is performed according to the solutions of the present invention, all optical signals are multiplexed into one optical signal based on polarization multiplexing, optical paths traveled by different optical signals differ slightly, and the optical power and the optical field energy distribution differ slightly between different optical signals in the finally multiplexed optical signal.