WDM Optical Components with Wavelength-Selective Coupling Lens
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Solution Overview
Problem
Conventional micro-mirrors in wavelength division multiplexing systems lack wavelength selectivity, leading to high optical loss and misalignment issues, which are detrimental in high-bandwidth optical transmission systems with polymer waveguides.
Innovation Solution
A wavelength division multiplexing system incorporating a waveguide with a coupling lens and a mirror, where an optical chip with a Bragg filter is positioned near the focal length of the lens to selectively transmit or reflect light signals based on wavelength, and a double pass lens array is used to increase misalignment tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional micro-mirrors are used to couple light from VCSELs into waveguide cores, then light coupling is achieved, but wavelength selectivity is lost and optical loss increases
Solution Approach 1:
The system segments the optical path by introducing separate optical paths for different wavelengths. Each wavelength channel has its own dedicated path from VCSEL through waveguide to photodiode, enabling wavelength-selective coupling without cross-talk and reducing overall optical loss by optimizing each path independently.
Solution Approach 2:
An intermediary optical element (such as a wavelength-selective coupler or filter) is introduced between the VCSEL array and waveguide cores to provide wavelength selectivity. This mediator enables selective coupling of specific wavelengths while blocking others, resolving the contradiction between achieving coupling efficiency and maintaining wavelength discrimination.
2Reliability
If conventional micro-mirrors with total-internal reflection are used, then light coupling is achieved, but misalignment tolerance is poor
Solution Approach 1:
The system employs dynamic alignment compensation mechanisms that allow the optical components to self-adjust or be actively realigned during operation. This dynamic approach maintains optimal coupling conditions despite fabrication errors or thermal drift, improving misalignment tolerance without sacrificing coupling efficiency.
Solution Approach 2:
The design incorporates adjustable parameters such as lens focal lengths, mirror angles, or waveguide core positions that can be optimized during assembly. By changing these parameters, the system compensates for fabrication irregularities and achieves both low optical loss and high misalignment tolerance.
3Productivity
If high core density is implemented in polymer waveguides, then channel density increases, but fabrication precision requirements increase
Solution Approach 1:
The high-density waveguide array is segmented into modular units with standardized pitch and dimensions. This segmentation enables repetitive fabrication processes that achieve high precision through consistency rather than complexity, allowing high channel density while maintaining manufacturability with conventional techniques.
Solution Approach 2:
The polymer waveguide structure uses homogeneous materials and uniform geometric parameters across all waveguide cores. This homogeneity simplifies the fabrication process by reducing the number of unique features that must be precisely controlled, enabling high core density without proportionally increasing manufacturing precision requirements.
4Speed
If photodiodes with small active regions are used, then bandwidth increases, but alignment precision requirements increase
Solution Approach 1:
The optical system is pre-aligned during assembly using temporary alignment fixtures or alignment marks before final bonding. This preliminary action ensures that the small photodiode active regions are precisely positioned relative to the waveguide cores, achieving both high bandwidth and acceptable alignment precision without requiring ultra-precision fabrication.
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 system achieves low optical loss and improved misalignment tolerance, enabling efficient de-multiplexing and multiplexing of multiple wavelengths in high-density optical systems, reducing bit error ratios and increasing bandwidth.
Implementation Method 1
The filter is configured to transmit a light signal at a first wavelength and to reflect received light signals at wavelengths other than the first wavelength
Implementation Method 2
The filter includes a plurality of alternating dielectric layers
Implementation Method 3
An optical chip is positioned near a focal length of the lens
Implementation Method 4
The mirror reflects incoming light signals out of the transmission path through the lens and further reflects light signals coming from the lens into the transmission path
Data Source
AI summary
Wavelength division multiplexing devices, and methods of forming the same, include a coupling lens and a waveguide, the lens being positioned over a mirror formed in a transmission path of the waveguide. The mirror reflects incoming light signals out of the transmission path through the lens and further reflects light signals coming from the lens and into the transmission path. An optical chip is positioned near a focal length of the lens. The optical chip has an optical filter configured to transmit a light signal at a first wavelength and to reflect received light signals at wavelengths other than the first wavelength.