Fiber-coupled Lasers series 51nanoFI-S with Faraday isolator (PM)

Low coherence laser source with polarization-maintaining fiber cable

Representative product images. Individual product images are found on the individual product pages.


Laser Diode Beam Sources of type 51nanoFI-S have reduced power noise, reduced coherence length and a lowered speckle contrast.
  • Integrated Faraday isolator for feedback protection (> 30 dB)
  • Reduced power noise: typ. < 0.15 % of Po (RMS, Bandwidth < 1 MHz)
  • Reduced coherence length: Coherence length ≈ 300 µm
  • Reduced speckle contrast
  • Various wavelengths from 405 nm to 1550 nm
  • Laser output power up to 27 mW
  • Polarization-maintaining fiber cable (Polarization Extinction Ratio PER ≥ 23 dB (for λ < 600 nm ≥ 21 dB))
  • FC APC connector (8°-polish), optional DIN AVIO or E-2000, end caps for wavelengths < 635 nm
  • With interlock and key switch (conform to EN 60825-1)
  • Beam profile is rotationally symmetric with Gaussian intensity distribution
Alternative: Laser Diode Beam Source 51nanoFI-N (OEM version without key switch or interlock)

  • Low noise, low coherence laser module (typ. < 0.15 % of Po (RMS, Bandwidth < 1 MHz))
  • With integrated Faraday isolator
Low noise, low coherence laser modulePM fiberWith integrated Faraday isolator


The fiber-coupled Laser Diode Beam Sources of type 51nanoFI-S have reduced power noise (typ. < 0.15 % of Po (RMS, Bandwidth < 1 MHz)), reduced coherence length (≈ 300 µm) and a lowered speckle contrast. Additionally sources of type 51nanoFI-S have an integrated Faraday isolator to protect the laser source from back-­reflection. 

Electrical features
The output power is adjustable using a potentiometer or using the two modulation inputs for analog and TTL. The electrical cable is 1.5 m long. There are two possible supply voltages 5 V or 12 V. Other electrical cables and connectors on request.

More details on electronics type: HP, H.

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 and a linear state of polarization. The fiber cable is equipped with an FC APC connector (8°-polish). Fiber connectors with end caps are used for wavelengths < 635 nm. The fiber cables have strain-relief and protective sleeving (Ø 3 mm). Standard cable length is 150 cm.

Fiber Options:

  • Other connector types including DIN, AVIO or E2000
  • Other fiber lengths
  • Incorporated vacuum feed-through

Faraday isolator
Faraday isolators are used to protect the laser sources from back-reflection, which causes mode hopping, laser noise, frequency instability and a shorter laser lifetime. The Faraday isolator has a high isolation > 30 dB.

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”

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

Technical data

Fiber-coupled Lasers series 51nanoFI-S with Faraday isolator (PM)

405 nm - 1550 nm
Power noise
typ. < 0.15 % of Po (RMS, BW < 1 MHz)
Coherence length
≈ 300 µm
Fiber cable
Fiber cable length
1.5 m (standard)
Fiber connector type
FC APC (standard)
Supply voltage
5 V or 12 V
Electr. cable length
1.5 m (standard)
Connector type (5V)
Connector type (12V)
Cable type
3 x AWG 26 C UL
analog and TTL
Operating temperature
15 - 35°C ± 0.5°C

Order Options

Order CodeWavelengthTyp.Output Power PoSupply VoltageFiber TypeConnectorEnd capElectronics TypeLaser ClassCasing Type
51nanoFI-S-405-1-Y07-P-12-4-28-0-150405 nm0.9 mW12 VPolarization-maintainingFC APCxHP2S1
51nanoFI-S-405-12-M29-P-12-4-28-0-150405 nm12 mW12 VPolarization-maintainingFC APCxHP3BS1
51nanoFI-S-445-15-G02-P-12-4-28-0-150445 nm15 mW12 VPolarization-maintainingFC APCxHP3BS1
51nanoFI-S-520-6-O11-P-12-4-28-0-150520 nm6 mW12 VPolarization-maintainingFC APCxHP3BS1
51nanoFI-S-635-1-H10-P-5-2-28-0-150635 nm0.9 mW5 VPolarization-maintainingFC APC H2S1
51nanoFI-S-640-15-H21-P-5-2-28-0-150640 nm15 mW5 VPolarization-maintainingFC APC H3BS1
51nanoFI-S-660-1-M01-P-5-2-28-0-150660 nm0.9 mW5 VPolarization-maintainingFC APC H2S1
51nanoFI-S-660-25-H26-P-5-2-28-0-150660 nm25 mW5 VPolarization-maintainingFC APC H3BS1
51nanoFI-S-785-10-Q06-P-5-2-28-0-150785 nm10 mW5 VPolarization-maintainingFC APC H3BS2
51nanoFI-S-808-16-G15-P-5-2-28-0-150808 nm16 mW5 VPolarization-maintainingFC APC H3BS1
51nanoFI-S-830-10-H19-P-5-2-28-0-150830 nm10 mW5 VPolarization-maintainingFC APC H3BS2
51nanoFI-S-850-15-TH11-P-5-2-28-0-150850 nm15 mW5 VPolarization-maintainingFC APC H3BS1
51nanoFI-S-980-2-TH4-P-5-2-28-0-150980 nm2 mW5 VPolarization-maintainingFC APC H3RS2
51nanoFI-S-1310-2-M14-P-5-2-28-0-1501310 nm2 mW5 VPolarization-maintainingFC APC H1 S1
51nanoFI-S-1550-4-Q04-P-5-2-28-0-1501550 nm4 mW5 VPolarization-maintainingFC APC H1 S1
Other types e.g. with single-mode fiber cable are available.                


Article_51Nano.pdf (Technote)

This downloads section only includes general downloads for the complete series.
Please access the individual product pages (using the product configurator, the product list, order options or the search button if you have a complete order code). Here you will find specific downloads including technical drawings or stepfiles.


Power Supply 12 V
Power Supply 5 V