Fiber-coupled low coherence laser source with polarization-maintaining fiber cable



The Laser Diode Beam Source of type 51nano-S-850-18-G17-P-5-2-28-0-150 has a reduced power noise, a reduced coherence length and a low speckle contrast.
  • Reduced power noise: typ. < 0.1 % of Po (RMS, Bandwidth < 1 MHz)
  • Reduced coherence length: coherence length ≈ 300 µm
  • Reduced speckle contrast
  • Wavelength: 850 nm
  • Laser output power: 18 mW
  • Polarization-maintaining fiber cable
  • FC APC connector (8°-polish)
  • Modulation analog and TTL
  • With interlock and key switch (conform to EN 60825-1)
Alternative: Laser Diode Beam Source 51nano-N (OEM version w/o key switch and w/o interlock)


The fiber-coupled Laser Diode Beam Source of type 51nano-S-850-18-G17-P-5-2-28-0-150 has a reduced power noise (typ. < 0.1 % of Po (RMS, Bandwidth < 1 MHz)), reduced coherence length (≈ 300 µm) and a lowered speckle contrast

Electrical features
The output power is adjustable using a potentiometer or using the two modulation inputs for analog and TTL. 

Fiber cable
The source is fiber-coupled to a polarization-maintaining fiber cable (standard, polarization extinction ratio ≥ 23 dB). As a result the beam profile is rotationally symmetric with Gaussian intensity distribution. The fiber cable is equipped with an FC APC type connector (8°-polish). The fiber cable has a strain-relief and a protective sleeving (Ø 3 mm). Standard cable length is 150 cm.


  • Single-mode fiber 
  • Core-centered (single-mode only)
  • Multiple fiber output cables (51nanoC, single-mode only)
  • Other connector types including FC PC, DIN or AVIO, or E2000
  • Other fiber cable lengths
  • Incorporated vacuum feed-through

Laser safety
The laser safety is conform to IEC 825 / EN 60825-1. 

  • Interlock chain for the remote deactivation of the laser
  • Laser power-up is only possible using the key switch
  • LED status indicator for “Laser ON”
  • For a quick start the laser is shipped with a interlock connector type BC0106F-iLCK

An OEM version is available as type 51nano-N without key switch or interlock which is not conform to EN 60825-1. 

Low coherence fiber coupled laser 51nano

Technical data


Order Code
Laser class
Center wavelength
850 ± 10 nm
0.7 - 4 nm
Output power
typ. 18 mW
Power adjustment
< 1 - 100 %
typ. < 0.1 % of Po (RMS, BW < 1 MHz)
≈ 300 µm
Fiber cable
Fiber type
0.076 ± 10 % (1/e2)
7.1 µm ± 10 % (1/e2)
≥ 23 dB
Fiber cable length
1.5 ± 0.05 m (standard)
Ø 3 mm with Kevlar strain-relief
FC APC (standard)
Power stability
max. 12 % power variation between 15°C and 35°C
Electronics type
Electr. cable length
1.5 ± 0.1 m (standard)
Supply voltage
5.0 ± 0.2 V
Max. current consumption*
260 mA
Modulation input connector
Modulation inputs
Max. input voltage
5 V
5 V
Voltage for Pmin / PO
< 0.8 V / > 2.4 V
0 V / 2.5 V
Input impedance
22 kOhm
22 kOhm
Max. modulation frequency
100 kHz
100 kHz
Time delay ON/OFF*
1.5/0.1 µs
2/0.3 µs
Rise / fall time*
1.0/1.0 µs
1.0/1.0 µs
* Typical value. Depends on laser diode.
Operating temperature
15 - 35°C ± 0.5°C
Warm-up time
approx.10 min
Air humidity
max. 90 % non-condensing
530 g
50 x 58 x 166 mm
Protection Class

Dimensions (for a complete dimensional drawing please refer to the downloads section)

Low coherence fiber coupled laser 51nano


Dimensional drawing
000829001100.pdf (Dimensional drawing)
STEP model
000829001100.stp (STEP model)
STEP model
000829001100.stp (STEP model, for registered users only)

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Power Supply 5 V
Interlock connector
Fiber Collimators single-mode/PM

Fiber Collimators for collimating light exiting a single-mode or polarization-maintaining fiber cable