Broadband and High-Speed Swept Sources
High-speed wavelength-swept laser technology offers versatile applications in optical coherence tomography (OCT), bio-chemical spectroscopy, and fiber-optic sensing. Particularly in recent years, swept laser technology has been critical in advancing OCT applications in the field of biomedical imaging and industrial imaging, imparting the advantages of real-time in-vivo diagnostics and high sensitivity.
To realize real-time clinical imaging and broad-base commercial deployment, compact, small, and stable swept sources are of utmost importance. To meet such demands, wavelength-flexible swept sources between 400 and 1700 nm with sweep rates from 1 to 150 kHz can be realized in a miniaturized optical butterfly package that also allows the integration of optical reference (k-clock) interferometers or other optical reference filters for spectral calibration.
The salient advantages of EXALOS’ swept source technology include:
- Wavelength flexibility: currently covering wavelengths from 800 nm to 1650 nm; potentially reaching the visible spectrum down to 400 nm.
- High phase stability: suitable for phase-sensitive applications such as Doppler-OCT.
- Ultra-stable long-term operation: enables spectral calibration with fixed remapping vectors.
- Clean imaging performance: no secondary coherence peaks as well as sharp and narrow PSF peaks without sidelobes throughout the imaging range.
- Symmetric bi-directional sweeps: allows high duty cycle and efficiency.
- Customizable bi-directional or uni-directional operation.
- Small size: optical module in compact butterfly package; packaged with electronics in hard-disk drive (HDD) form factor.
EXALOS Swept Sources for Optical coherence tomography (OCT)
EXALOS is the leading supplier of high-bandwidth and high-power SLEDs (EXS) for ophthalmic and medical OCT applications.
EXALOS is also offering high-performance driver boards for SLEDs (EBD) featuring ultra-low-noise and ultra-high current stability with zero long-term drift. EXALOS is also a key supplier of high-speed swept sources (ESS), for wavelength ranges from 800 to 1600 nm, and of ultra-low-noise balanced receivers (EBR).
The OCT images were taken with EXALOS SLEDs, its combined broadband light sources (EBS), allowing resolutions down to two microns in tissue, or with EXALOS’ high-speed and broadband swept sources.
Left: 3D OCT cross-section of the macular hole of a human retina, recorded with an 840-nm broadband SLED EXS210022 and a high-resolution spectrometer (courtesy of Prof. Rainer A. Leitgeb, Center of Biomedical Engineering and Physics, Medical University of Vienna).
TOP: 2D OCT cross-section (B-scan) of a human retina, recorded with a 1070-nm broadband SLED source EBS4C34 and a high-resolution spectrometer with an InGaAs camera (courtesy of Prof. Wolfgang Drexler, Center of Biomedical Engineering and Physics, Medical University of Vienna).
Spectra of swept sources in different spectral regions
Swept Source Architecture
The dashed line represents the optical butterfly module, indicating
that the entire laser cavity is contained inside the module.
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Hybrid optical packaging platform
Compact OEM Swept Source Module
The swept source optical modules (SSOMs) described above are assembled on electronic driver boards. Those fiber-coupled turn-key swept sources are available either as a bench-top version or as an OEM module in 3.5” HDD format (footprint 101.6mm x 147.0mm) that can be mounted inside a disk cage of a PC.
The OEM module operates on 12V and 24V DC with a typical power consumption of 10 Watt.
EXALOS Swept Source products
Besides complete, independent devices, we provide an optical module (SSOM), mounted on a compact electronic driver board. This board enables OEM Swept Sources (with metal case) in 3.5” HDD form factor.
Bridge the Gap.
Superluminescent light-emitting diodes (SLEDs) are broadband semiconductor devices that are closely related to their more commonly known relatives, laser diodes and light-emitting diodes (LEDs).
Application example: SLEDs can be used in fiber optic pressure sensors for static strain (load) or dynamic strain (vibration) measurements as well as temperature measurements in structures such as suspension bridges.