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Technical Overview
The Broadsweepers series is a new family of tunable semiconductor lasers intended for
applications that require fast and precision wavelength tuning with high sweep-to-sweep
reproducibility of the "instantaneous" wavelength. Among all possible applications,
the most important are Optical Coherence Tomography (including Full Field OCT),
biomedical imaging, interferometry, optical spectroscopy, fiber-optic sensing and
optical component characterization.
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Superlum BS-840-1 Tunable Semiconductor Laser.
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The optical scheme of the Broadsweeper is based on an external fiber-optic ring cavity and
a broadband Semiconductor Optical Amplifier (SOA), working as a gain medium. The wide bandwidth of
the SOA modules used, and their high fiber-to-fiber gain allow
wavelength tuning range of more than 50 nm at 3 mW of output power
(and at 20 mW in case of an additional booster unit).
The wavelength tuning technique involves the use of a specially developed narrowband
Acousto-Optical Tunable Filter (AOTF). The AOTF is actively thermally stabilized for
high spectral stability of laser radiation. High wavelength accuracy and excellent wavelength
reproducibility in sweep operation are ensured by "akinetic" cavity design with no moving
components inside. Due to the perfect AOTF tuning characteristic, the laser provides
k-linear wavelength tuning over a wide spectral range.
All other components comprising AOTF unit and laser cavity feature a unique customized design
perfectly fitted for broadband spectral applications. Aberration-free aspherical lenses are used
for maximizing the coupling efficiency to optical fibers and minimizing the insertion losses of
AOTF unit over entire wavelength tuning range. The filter and its optics are packaged into one
monolithic metal housing, thereby ensuring reliable day-to-day operation without misalignment.
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The Superlum acousto-optical tunable filter with a fiber-optic delivering
system is at the heart of the Broadsweeper.
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The external cavity of the laser uses a PANDA-type polarization maintaining (PM) fiber.
This ensures a well-defined state of light polarization and its high stability in time and
over the tuning range. Most of fiber-optic components are built by using the fast-axis-blocking
technology that also guarantees high values of the PER (> 18 dB) at the laser output.
Non-boosted models are also characterized by extremely low spontaneous emission background
(~−50 dB).
The driving electronics ensures precise, reliable and safe control of the instrument in
all modes of operation. It provides all the necessary laser diode protective measures such
as on-off transients' suppression, over-temperature protection, open-circuit protection and
laser current limitation by a pre-set safe value. Specially developed fast optical power
control loop enables a flat-top-shaped tuning characteristic at all specified sweep speeds for
all models offered.
The laser provides the following modes of operation:
- CW operation at any single wavelength within the full tuning range.
The operating wavelength is adjustable from the front panel or from a computer.
Under computer control, typical switching between two different wavelengths is
done in less than 100 ms. The user can select any wavelength within the
full wavelength range with a 50-pm resolution.
- Continuous sweeps over the full tuning range or over the band of interest (within the
full tuning range) not shorter than 5 nm. Both the internal triggering and
the external triggering are available.
- Continuous switching between two any wavelengths within the full tuning range at
a certain repetition frequency. The range of frequencies includes 13 factory-set values.
Customized settings for the repetition frequency are possible upon request.
When internally triggered, the device produces synchronizing pulses. In the external triggering
mode, the device responds to incoming TTL-compatible trigger signals. BNC connectors for
triggering/synchronization are located on the back panel.
The output optical power of the Broadsweepers without internal boosters is 3 mW.
It is boosted to 20 mW in the devices with internal optical boosting units.
The optical output is provided through the front-panel narrow key (2.0 mm)
FC/APC mating sleeve. Each device is supplied with a PM optical patch cable.
The output polarization is aligned to the slow axis of the patch cable. An SM optical patch
cable is also available on request.
Remote Control Capability
The device has an RS-232 DTE port for remote control from a computer.
The necessary connectivity software is supplied with the instrument.
Laser Safety Measures
To fulfill the requirements of ICE 60825-1 Ed. 3 2014-05, each instrument is equipped with
laser safety measures including: the master key control, remote interlock connection,
visual/audible alarm, informational warning stickers, etc.
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Informational labels about laser hazard meet the requirements of ICE 60825-1
Ed. 3 2014-05.
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Standard Models Available for Ordering
Depending on the spectral band and sweep speed, there are several models of the product to choose.
Refer to the table below for the standard versions of the product.
| Model |
Tuning Range (nm) |
Output Power (mW) |
Sweep Speed (nm/s) |
Linewidth (nm) |
| 765 – 815 nm Spectral Range |
| BS-785-1 |
50 |
3 |
2 – 10,000 |
0.06 |
| BS-785-1-HP* |
50 |
20 |
2 – 10,000 |
0.06 |
| BS-785-2 |
50 |
3 |
100 – 100,000 |
0.12 |
| BS-785-2-HP* |
50 |
20 |
100 – 100,000 |
0.12 |
| 805 – 880 nm Spectral Range |
| BS-840-1 |
75 |
3 |
2 – 10,000 |
0.06 |
| BS-840-1-HP* |
75 |
20 |
2 – 10,000 |
0.06 |
| BS-840-2 |
75 |
3 |
100 – 100,000 |
0.12 |
| BS-840-2-HP* |
75 |
20 |
100 – 100,000 |
0.12 |
| 900 – 980 nm Spectral Range |
| BS-930-1 |
80 |
3 |
2 – 10,000 |
0.09 |
| BS-930-1-HP* |
80 |
20 |
2 – 10,000 |
0.09 |
| BS-930-2 |
80 |
3 |
100 – 100,000 |
0.15 |
| BS-930-2-HP* |
80 |
20 |
100 – 100,000 |
0.15 |
| 1020 – 1090 nm Spectral Range |
| BS-1060-1 |
70 |
3 |
2 – 10,000 |
0.09 |
| BS-1060-1-HP* |
70 |
20 |
2 – 10,000 |
0.09 |
| BS-1060-2 |
70 |
3 |
100 – 100,000 |
0.15 |
| BS-1060-2-HP* |
70 |
20 |
100 – 100,000 |
0.15 |
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| * INCLUDES INTERNAL OPTICAL POWER BOOSTER |
General Specifications
| Power Requirements: |
110 VAC or 220 VAC, 50 Hz or 60 Hz |
| Power Consumption: |
20 W / 25 W* |
| Operating Temperature: |
+15 °C to + 30 °C |
| Storage Temperature: |
0 °C to +40 °C |
| Outline Dimensions (W × H × D): |
257 × 170 × 325 mm / 362 × 160 × 326 mm* |
| Weight: |
9 kg / 12 kg* |
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| * FOR MODELS WITH INTERNAL OPTICAL POWER BOOSTER |
For more information on each model, please download
Technical Product Specification (338 KB) .
Product Customization Capabilities
Superlum offers product customization services. A number of the operating characteristics of
the product (e.g. the output power level, target wavelengths for the tuning range, the sweep
speed limits, etc.) are available for modification according to your requirements.
Please contact us for
further discussion of your tunable laser requirements.
Technical Documentation
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