Transmitting Optical Module With Dual Lens Alignment
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Solution Overview
Problem
Existing transmitting optical modules face challenges in achieving high-frequency operation beyond 40 Gbps, particularly in wavelength division multiplexing (WDM) systems, where efficient optical coupling and alignment of semiconductor laser diodes (LDs) with waveguides are critical for maintaining communication capacity.
Innovation Solution
The optical module incorporates a waveguide device with an optical waveguide mounted on a waveguide carrier, aligned with marks on the carrier, and a dual lens system for precise optical coupling between LDs and waveguides, using a carrier to ensure accurate alignment and reduce scattering, thereby enhancing optical coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple lenses, mirrors, and wavelength selective filters are used for multiplexing optical signals, then optical coupling efficiency can be improved, but device complexity increases
Solution Approach 1:
The patent combines multiple optical functions (multiplexing, wavelength selection, beam combining) into a single integrated planar lightwave circuit (PLC) device. The PLC integrates multiple waveguides with different propagation constants on a single substrate, eliminating the need for separate lenses, mirrors, and wavelength selective filters that would otherwise be required to achieve the same functionality. This merging of functions maintains optical coupling efficiency while significantly reducing device complexity.
Solution Approach 2:
The patent introduces a dedicated alignment mark structure as an intermediary element to facilitate precise alignment between the laser diode and the waveguide input. The alignment mark serves as a mediator that enables accurate positioning without requiring complex alignment mechanisms or adjustments, thereby simplifying the overall system while maintaining high optical coupling efficiency.
2Manufacturing precision
If alignment marks are provided on the carrier and waveguide carrier for precise positioning, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent implements alignment marks that are pre-formed on both the carrier and the waveguide carrier during the manufacturing process. These marks are created in advance as integral parts of the respective components, enabling precise alignment to be achieved simply by matching the marks during assembly. This preliminary preparation of alignment features eliminates the need for complex alignment mechanisms or post-assembly adjustments, thereby improving manufacturing precision without significantly increasing device complexity.
3Reliability
If the waveguide device is mounted with the primary surface facing and in contact with the waveguide carrier, then optical coupling efficiency improves, but ease of manufacture decreases
Solution Approach 1:
The patent divides the mounting structure into separate functional components: the carrier, the waveguide carrier, and the planar lightwave circuit device. This segmentation allows each component to be manufactured and optimized independently, with the primary surface of the PLC device being specifically designed for optimal optical coupling when mounted on the waveguide carrier. The modular segmented structure maintains ease of manufacture through standardized mounting interfaces while achieving high optical coupling efficiency through optimized surface contact geometry.
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 improves optical coupling efficiency by allowing precise alignment and reduced scattering, enabling effective multiplexing of optical signals at high frequencies, such as 100 Gbps, by using a dual lens system and a waveguide carrier for accurate positioning and adhesion.
Implementation Method 1
a dual lens system for precise optical coupling between LDs and waveguides
Implementation Method 2
The waveguide device includes an optical waveguide in a primary surface
Implementation Method 3
an optical signal that multiplexes a plurality of sub-signals each having wavelengths different from each other that is, the wavelength division multiplexing (WDM)
Data Source
AI summary
A transmitting optical module that includes multi-laser diode (LDs) and a planar lightwave circuit (PLC) to multiplex optical beams each output from the optical sources is disclosed. The PLC is mounted on a carrier through a WG carrier in upside down arrangement. The LDs are also mounted on the carrier through an LD carrier. The LDs and the PLC are optical coupled with two lenses each having respective optical axes offset from the other such that the optical coupling of the optical beam inputting the PLC becomes a maximum.