Polarization Independent Optical Device for Fiber Optics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical devices in fiber optic communications are polarization dependent, leading to signal degradation due to polarization dependent loss (PDL) and polarization mode dispersion (PMD), and cannot simultaneously perform optical signal add/drop multiplexing at different wavelengths.
Innovation Solution
A polarization independent optical device is designed with an input/output preprocessing optical path and multiple add/drop optical paths, each containing a microring and a polarization splitter and rotator (PSR), allowing for simultaneous dropping and adding of optical signals across various wavelengths by processing both TE and TM modes uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional optical device with micron-scale waveguide is used, then the device size is reduced, but polarization dependent loss (PDL) and polarization mode dispersion (PMD) are generated causing signal degradation
Solution Approach 1:
The device is segmented into multiple functional modules: polarization beam splitters (PBS) divide the waveguide into separate TE and TM mode paths, polarization rotators (PR) are placed at specific segments to rotate polarization states, and microring filters are segmented to handle different wavelength channels. This segmentation allows independent optimization of each polarization mode path, eliminating PDL and PMD while maintaining compact size.
2Reliability
If polarization beam splitting and polarization rotation are performed to eliminate PDL and PMD, then signal quality is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple functions into integrated components: the polarization beam splitter and polarization rotator are combined in a systematic arrangement where PBS separates modes and PR rotates them to the same polarization state. The microring filter units are merged with these polarization control elements to form integrated add/drop multiplexing functions. This merging reduces the overall system complexity compared to separate handling of each function.
Solution Approach 2:
The optical device is designed with multi-functionality to handle both add and drop operations for multiple wavelength channels simultaneously. The same structural framework with PBS, PR, and microring filters serves universal purposes: separating polarization modes, rotating polarizations, filtering wavelengths, and performing add/drop multiplexing. This universality reduces device complexity by avoiding separate dedicated structures for each function.
3Reliability
If separate handling of TE and TM modes is performed, then polarization independence is achieved, but the inability to simultaneously add and drop optical signals at different wavelengths occurs
Solution Approach 1:
The device employs dynamic wavelength selection capability where the microring filters can be tuned to resonate at different wavelengths. This dynamic adjustment allows the same device structure to add or drop different wavelength channels as needed. The polarization control mechanisms (PBS and PR) work dynamically for any input wavelength, maintaining polarization independence while enabling versatile add/drop multiplexing operations across the wavelength spectrum.
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
The device ensures polarization independence, reducing PDL and PMD, and enables simultaneous optical signal add/drop multiplexing at different wavelengths, enhancing the quality and versatility of fiber optic communications.
Implementation Method 1
When a wavelength of an optical signal corresponding to the QTE is λ1 that meets a resonance condition of the microring 103
Implementation Method 2
an optical signal at each wavelength in the WDM signal is split into two components, that is, a TE mode and a TM mode, by using a polarization beam splitter (Polarization beam splitter, PBS) 101
Implementation Method 3
PTM is converted to a TE polarization mode by using a polarization rotator (Polarization rotator, PR) 102
Data Source
Figure 1~2B
Figure 2C
Figure 3
AI summary
This application relates to the field of fiber optic communications, and discloses a polarization independent optical device. The polarization independent optical device includes an input/output preprocessing optical path and M add/drop optical paths. Any add/drop optical path may be configured to drop a first QTE and a first PTE that meet a resonance condition of a microring included in the add/drop optical path, that is, each add/drop optical path may be configured to drop a desired optical signal. Any add/drop optical path may also be configured to transmit an input optical signal to the input/output preprocessing optical path, that is, each add/drop optical path may also be configured to add a desired optical signal. Therefore, when any of the M add/drop optical paths is configured to drop a desired optical signal, another add/drop optical path may be configured to add a desired optical signal. In other words, the polarization independent optical device provided by this application can simultaneously drop a desired optical signal and add a desired optical signal.