Multichannel Optical Receiver for OCT Acquisition Speed
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Solution Overview
Problem
Current swept source optical coherence tomography (OCT) systems face limitations in acquisition speed due to laser safety regulations and complexity, leading to degraded signal-to-noise ratio and motion artifacts, especially in in vivo applications, where faster A scan acquisition is necessary without increasing laser complexity.
Innovation Solution
A multichannel optical receiver system that utilizes a wavelength tuneable or steppable optical source and an interferometer to separate light into sample and reference beams, forming interferograms with distinct carrier frequencies, which are detected by a photodetector array in parallel, allowing for faster A scan acquisition and reduced motion artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional single-channel swept source OCT systems are used, then system complexity is low, but acquisition speed is slow leading to motion artifacts
Solution Approach 1:
The invention divides the optical detection into multiple independent channels (at least two), where each channel detects light at a different wavelength range simultaneously. This segmentation enables parallel acquisition of spectral data, significantly increasing productivity while maintaining manageable system complexity through modular channel design
Solution Approach 2:
The invention adds a spectral dimension to the detection system by using multiple channels tuned to different wavelength ranges. Instead of sequentially scanning wavelengths in a single channel, the system simultaneously detects multiple wavelength bands across different spatial channels, transforming the detection approach from temporal to spatial-spectral parallelism
2Reliability
If laser power is increased to improve signal-to-noise ratio, then signal quality improves, but laser safety regulations are violated
Solution Approach 1:
The total optical power is divided and distributed across multiple detection channels, each receiving a portion of the spectrum. This allows the system to maintain adequate signal-to-noise ratio in each channel without concentrating excessive power in a single beam, thereby complying with laser safety limits while preserving detection quality
Solution Approach 2:
The invention combines the signals from multiple channels, each operating at safe power levels, to achieve the overall signal quality needed for reliable OCT imaging. The parallel detection across channels effectively merges the useful signal information while keeping individual channel power within safety limits
3Productivity
If scanning speed is increased to reduce motion artifacts, then image quality improves, but laser safety regulations prevent increasing applied power
Solution Approach 1:
The spectral scanning is divided into multiple parallel channels, each covering a specific wavelength range. This enables the system to acquire data from multiple spectral segments simultaneously, effectively increasing the scanning speed and reducing acquisition time to minimize motion artifacts, while maintaining signal-to-noise ratio through parallel detection
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 enables significantly faster A scan acquisition compared to conventional camera-based systems, improving image acquisition speed and reducing motion artifacts in OCT imaging, particularly for in vivo applications, while maintaining system simplicity.
Implementation Method 1
mix said plurality of returning probe beams with said one or more reference beams to form an interference pattern comprising a plurality of interferograms having a set of carrier frequencies
Implementation Method 2
detect said interference pattern with a photodetector array configured to be read out in parallel
Data Source
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AI summary
Methods and apparatus are presented for multichannel optical coherence tomography. Light from a wavelength tuneable or steppable optical source is separated into one or more sample beams and one or more reference beams, and the one or more sample beams directed onto a sample to form one or more interaction regions. A plurality of returning probe beams are collected and mixed with the one or more reference beams to form an interference pattern comprising a plurality of interferograms having at least two distinct carrier frequencies. The multichannel optical apparatus can be provided with polarisation discrimination by mixing the returning probe beams with two orthogonally polarised reference beams to form one or more interference patterns each comprising a plurality of interferograms having at least two distinct carrier frequencies. In preferred embodiments each interferogram has a distinct carrier frequency, which may be provided by ensuring that each returning probe beam has a distinct propagation angle with respect to a reference beam. Also presented is a means of generating a plurality of beamlets from a sample beam using a nonreciprocal optical splitter configured to split a beam propagating in a forwards direction into a plurality of beamlets, and to transmit without splitting a beam propagating in the reverse direction.