Hollow-Core Photonic Bandgap Fiber for Compact Atomic Sensing
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Solution Overview
Problem
Conventional glass reference cells filled with gases or atomic vapors are not durable, stable, or compact enough for field use and are limited by short absorption path lengths, making them unsuitable for rugged and compact applications.
Innovation Solution
A robust Hollow-Core Photonic Bandgap Fiber (HCPBF) chamber is developed, allowing for the creation of a compact, rugged, and long path length frequency reference cell by filling the hollow core with atoms or molecules and fusion splicing it with solid core fibers, enabling mass production and improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional glass reference cells are used, then atomic and molecular sensing can be performed, but the device is fragile, bulky, and not durable for field use
Solution Approach 1:
The patent replaces fragile glass cells with a flexible fiber optic cable structure that has a hollow core. This flexible fiber structure eliminates the fragility of glass while maintaining the sensing functionality, making the device suitable for field use and portable applications.
Solution Approach 2:
The patent embeds the sensing functionality within a standard fiber optic cable structure. The hollow core of the fiber contains the gas or vapor, while the fiber itself provides mechanical protection and flexibility. This nested structure integrates multiple functions (sensing, protection, flexibility) into a single compact device.
2Length of moving object
If conventional glass reference cells are used, then atomic and molecular sensing can be performed, but the absorption path length is limited to 200 mm
Solution Approach 1:
The patent transitions from a linear glass cell geometry to a coiled fiber optic cable geometry. By arranging the fiber in a coil or loop configuration, the absorption path length is extended along the curved path while maintaining a compact overall device volume. This allows achieving longer path lengths (e.g., several meters) without proportionally increasing the device footprint.
Solution Approach 2:
The patent uses a flexible fiber optic cable that can be segmented and arranged in various configurations (coils, loops, straight sections) to achieve different effective path lengths. The fiber can be divided into multiple sections that are coiled together, allowing the absorption path to be extended in a compact space through spatial arrangement rather than simple linear extension.
3Ease of manufacture
If conventional glass reference cells are used, then frequency reference sensing can be performed, but the device is not suitable for mass production
Solution Approach 1:
The patent uses standard fiber optic cable technology that is already mass-produced for telecommunications and other applications. By leveraging this existing, well-established manufacturing infrastructure, the sensing device can be produced at scale using conventional fiber drawing and assembly processes, significantly improving manufacturability and reducing costs.
Solution Approach 2:
The fiber optic cable structure inherently provides its own mechanical protection, flexibility, and optical guidance. The cladding and coating layers of the fiber serve multiple functions (structural support, protection, optical confinement) without requiring additional external components, simplifying the manufacturing process and enabling easier mass production.
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 HCPBF chamber provides a durable, compact, and mass-producible solution for atomic and molecular sensing, offering extended path lengths and improved stability compared to traditional glass cells, while maintaining single-mode functionality and compatibility with standard fiber systems.
Implementation Method 1
Hollow waveguides fibers fabricated for infrared transmission can be filled with gas but they are multimode and not suited for coupling to single mode fibers. The inventors recognized that HCPBFs, having holes in the core as illustrated in FIG. 1, may be an ideal vessel to contain a gas which may be used as a frequency reference. These HCPBFs 100 confine light at specific frequencies by coherently backscattering light into the inner core 100b.
Implementation Method 2
the HCPBF segment is cleaved to form two HCPBF pieces
Implementation Method 3
at least two solid core fiber segments fused to the distal ends of the HCPBF pieces
Data Source
AI summary
A robust and rugged method for sensing atoms and molecule using a small hybrid Hollow-Core Photonic Bandgap Fiber (HCPBF) is described. The hybrid fiber and associated chamber apparatus is amenable to mass production and can be used for wavelengths of light from 400 nm to 2000 nm.