|Matched-Pair SLD Characteristics|
|SLD Output||SLD A||SLD B||A + B|
|Central Wavelength - Typical||1225 nm||1340 nm||1300 nm|
|FWHM Bandwidth - Typical||80 nm||110 nm||200 nm|
|10dB Bandwidth - Typical||100 nm||150 nm||235 nm|
|Fiber-Coupled Power||>10 mW per channel|
|Noise, Typical||<0.2% (Source Dependent)|
|Adjustment Range||0 - Full Power|
|Temperature Control||14.00 to 30.00 °C|
|Operating Temperature||10 - 30 °C|
- Superluminescent Diode (SLD) Tuned for OCT Applications
- Dual SLD Light Sources for Broadband Spectral Output
- Four Channel Output
- 1300 nm Center Wavelength
- >10 mW Output per Channel
- FC/APC Connector
- Independent Operation for Each SLD
- Controls on Front Panel and via USB Interface
Thorlabs has partnered with Praevium Research to develop superluminescent diode (SLD) light sources for OCT applications. In OCT imaging systems, the optical bandwidth of the light source is inversely proportional to the axial resolution. To provide higher axial resolution than currently possible with a single SLD, the LS2000B features a dual SLD arrangement. This dual SLD feature produces an extended broadband SLD light source ideal for high resolution OCT imaging applications.
The SLDs are designed so that their emission spectra are offset yet, when combined (matched-pair), the deviation from normal Gaussian distribution based on that offset is minimized to less than 3 dB (see typical spectrum below). The output of the two fiber-pigtailed SLDs are fiber coupled to provide a single extended bandwidth (200 nm, typical) light source.
The LS2000B extended broadband SLD light source packages the matched-pair SLDs into a single compact housing. Like our other 1300 nm SLD for OCT, these SLDs have an integrated isolator, thermistor, and TEC element for optimal performance. The LS2000B front panel provides independent control of the output of each SLD. In addition, each SLD has a front panel enable/disable output button as well as a reset to the factory configuration.
The LS2000B SLD light source can be completely controlled using the front panel interface, however the unit can also be controlled through a PC via the USB connection on the back of the unit. The LS2000B can be controlled through the provided software as well as through command line language via the USB port.
There are four FC/APC fiber connectors in the front panel of the LS2000B. The first two channels access to the output of the two independent SLDs. The remaining two channels provide extended bandwidth output by combining the output of the two SLDs. Each combo-channel will have a bandwidth greater than 170 nm and output power greater than 10 mW from each channel. The LS2000B can operate two channels, 1 and 2 or 3 and 4, simultaneously.
OCT Scan of an Onion Skin
This extended light source can be used in OCT imaging systems to produce images with a resolution of ~3 μm in biological (n = 1.33) samples. The images below demonstrate the increased resolution obtained when the light source is switched from a 90 nm Bandwidth single SLD source to a 200 nm Extended Bandwidth SLD source.
Image Taken Using a 90 nm Bandwidth SLD Image Taken Using a 200 nm Extended Bandwidth SLD
OCT Imaging with a 90 nm bandwidth (FWHM) source provides ~9 μm of axial resolution, as demonstrated in the top image of an onion skin. Incorporating an Extended Broadband SLD, based on matched-pair SLD light sources that together provide a bandwidth of 200 nm (Typical, FWHM), enables imaging at axial resolutions less than 4 μm, as demonstrated above. The higher resolution provided by the Extended Broadband SLD enables visualization of distinct layers in the onion skin.