Ultra-small-pitch Optical Filter Assembly with Beam Compression
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Solution Overview
Problem
Current optical filtering device assemblies face challenges in achieving small channel spacing due to difficulties in manufacturing and assembling thin-film filters, leading to high costs and complexity, especially for devices with low channel counts, and this affects the spacing of photo-diode arrays in electrical subassemblies.
Innovation Solution
An ultra-small-pitch optical filter assembly is designed, comprising a fiber collimator, a WDM filter module, and an optical lens assembly that includes a contracting lens module and a steering lens module, which reduces the physical spacing of optical beams from a first pitch to a second pitch, allowing for closer alignment of photodiodes and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If thin-film filters with smaller channel spacing are manufactured using conventional approaches, then channel spacing is reduced, but manufacturing difficulty and associated loss increase significantly
Solution Approach 1:
The patent introduces a waveguide divider as an intermediary component between the input optical signal and the thin-film filters. This waveguide-based intermediate stage performs preliminary signal distribution, allowing the subsequent thin-film filters to operate at relaxed spacing while achieving the desired ultra-small-pitch output spacing through the combined optical path geometry.
2Length of moving object
If PLC-based waveguide dividers are used to achieve smaller channel spacing, then channel spacing is reduced, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent segments the optical filtering function into distinct modular components: a waveguide divider module for signal distribution and a thin-film filter module for wavelength selection. This segmentation allows each module to be optimized independently, with the waveguide section handling spatial distribution and the thin-film section handling spectral filtering, thereby reducing overall system complexity compared to integrated PLC solutions.
3Ease of manufacture
If larger spacing of photo-diode array is used in electrical subassembly, then manufacturing is easier, but overall cost and device size increase
Solution Approach 1:
The patent transforms the spatial relationship between optical beams and photo-diodes by introducing an inclined optical path dimension. The optical beams are directed at an angle to the photo-diode array plane, allowing the use of larger-spaced photo-diodes while maintaining compact overall device footprint through the three-dimensional optical path configuration rather than being constrained to a single planar dimension.
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 solution effectively reduces the physical spacing between optical beams, facilitating the use and manufacturing of electrical subassemblies with smaller photo-diode arrays, thereby lowering the overall cost and complexity of optical subassemblies while maintaining high channel isolation.
Implementation Method 1
a fiber collimator 10 for accepting an optical signal
Implementation Method 2
a WDM filter module 20 for de-multiplexing the optical signal from the fiber collimator into a plurality of optical beams based on their wavelength
Implementation Method 3
a contracting lens module 31 that has a front end of convex surface facing the WDM filter module; and a rear end of concave surface facing the steering lens module
Implementation Method 4
the steering lens module further includes a micro-lens array mounted at a front end surface thereof, the micro-lens array includes at least four micro-lenses that provide focus of at least four respective optical beams
Implementation Method 5
the steering lens module further includes a rear surface that is inclined in an angle to optical beams passing through the micro-lenses, the inclined rear surface steers the optical beams from a first direction towards a second direction
Data Source
AI summary
Embodiments of present invention provide an ultra-small-pitch optical filter assembly. The assembly includes a fiber collimator being able to receive an optical signal; a WDM filter module being able to de-multiplex the optical signal from the fiber collimator into multiple optical beams; and an optical lens assembly being able to receive the multiple optical beams from the WDM filter module and to reduce a physical spacing among the multiple optical beams from a first pitch D to a second pitch d, wherein D/d A method of fabricating the ultra-small-pitch optical filter assembly is also provided. A method of producing a set of optical beams with ultra-small-pitch of spacing is provided as well.