Common Path Interferometer for Stable OFDI Imaging
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Solution Overview
Problem
Existing optical frequency domain imaging (OFDI) devices face challenges in maintaining sensitivity and stability due to endoscope motion and environmental perturbations, and require complex and expensive polarization diversity detection, as well as difficulties in interchanging disposable parts with accurate length matching.
Innovation Solution
The use of common path interferometers with two independent propagation modes in an optical waveguide, where the reference light travels the same path as the signal light, and a swept frequency light source with a mode converter and mode selective reflector to direct and control light in these modes, allowing for stable imaging despite mechanical movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarization diversity detection is used to maintain sensitivity and stability, then imaging quality is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the reference light path and signal light path into a single common path, eliminating the need for separate polarization diversity detection systems. The mode director combines both paths, allowing interference to occur directly without requiring complex polarization maintenance mechanisms, thus reducing device complexity while maintaining imaging stability.
Solution Approach 2:
The common path interferometer serves multiple functions simultaneously: it provides reference light, signal light generation, and interference detection all within a single integrated optical path. This multi-functionality eliminates the need for separate polarization diversity detection components, reducing both device complexity and cost while maintaining imaging sensitivity.
2Ease of operation
If disposable parts are interchanged frequently, then ease of operation is improved, but manufacturing precision requirements increase due to length matching
Solution Approach 1:
The mode director automatically compensates for length variations in disposable parts through its optical design. When disposable parts are interchanged, the system self-adjusts by maintaining the common path geometry, eliminating the need for precise length matching between different disposable components and enabling easy interchangeability.
Solution Approach 2:
The patent changes the optical path parameters by using a common path configuration where the reference and signal lights travel together. This parameter change makes the system insensitive to absolute path length variations, allowing disposable parts with different lengths to be interchanged without requiring precise manufacturing tolerances.
3Ease of operation
If endoscope motion and environmental perturbations occur, then ease of operation is maintained, but imaging stability deteriorates
Solution Approach 1:
By merging the reference and signal light paths into a common path, the patent ensures that both beams experience identical environmental perturbations and mechanical movements. Since they travel together through the same optical components, any external disturbances affect both paths equally, maintaining their relative phase relationship and preserving imaging stability despite endoscope mobility.
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 approach stabilizes the relative phase between light modes, reducing noise and complexity, enabling easy interchangeability of disposable parts and maintaining high sensitivity imaging immunity to endoscope motion and environmental perturbations.
Implementation Method 1
a swept frequency light source that produces an optical probe beam and sweeps an optical frequency of the optical probe beam in time
Implementation Method 2
a waveguide to receive and guide optical probe beam in a first propagation mode and a second propagation mode different from the first propagation mode
Implementation Method 3
a mode director that directs the optical probe beam from the swept frequency light source into the waveguide and to couple light of the reflected first portion and the reflected second portion out of the waveguide without changing respective propagation modes
Implementation Method 4
Optical frequency domain imaging (OFDI), which may also be known as swept source optical coherence tomography uses a wavelength-swept light source to probe the amplitude, phase, polarization and spectral properties of back scattering light from the tissue. OFDI offers intrinsic signal-to-noise ratio (SNR) advantage over the time domain techniques because the interference signal can be effectively integrated through a Fourier transform
Data Source
AI summary
Optical devices and techniques for imaging and measuring targeted objects, e.g., tissues.