LIght Detection And Ranging (LIDAR)

# #

The generic term of LIDAR for LIght Detection And Ranging finds its use nowadays in many different systems and applications. Applications range from the scanning of surroundings to create a 3-D digital map of obstacles (for instance in autonomous driving applications) to atmospheric Lidars that detect gases or aerosol particules (for instance in environmental applications). Another well spread application is the detection of atmospheric turbulences to secure wind-turbines operation or airports.

 

All these systems have different requirements in terms of wavelength, power and pulse profiles. iXblue Photonics offers a wide range of specialty fibers and Electro-Optic Modulators (EOMs) that can answer the various challenges of Lidar applications.

#

Lidar schematic

A typical LIDAR setups are based on Time of Flight (TOF) measurement where high power optical pulses (duration in order of nanoseconds) are bounced from objects in the environment. Accurate measurement of the time the pulses take to return to the sensor after reflection are computed to draw a 3D map of the surroundings.
As an example, below is a principle diagram for a MOPFA Lidar (Master Oscillator Power Fiber Amplifier) for wind monitoring application.

 

Fig. 2:  Coherently combined pulsed amplifier setup. Output O1 carrries the total power of outputs A1 and A2

The Lidar performance depends strongly on the pulse characteristics: high energy pulses and beam quality (for longer reach), high repetition rate (for faster acquisition), narrow linewidth (for higher measurement resolution).
Unfortunately all the above characteritics are contributing to lower the threashold power level at which Stimulated Brillouin Scattering (SBS) becomes a limiting factor. Even at “eye safe” wavelengths, power densities in the core of the fiber prevent pulse peak power.
The solution: A highly doped, Large Mode Area (LMA), low NA, Polarisation Maintaining fiber with a pump guide to harness the power of high-power laser diode.
iXblue IXF-2CF-EY-PM-30-300 combines all the characteritics above enabling high power operation. SBS threasholds are reached only at very high power thanks to the large single mode area reducing the power density. The high absorption allows for short gain fiber length pushing further the SBS power threshold. The low NA allows for a good beam quality.
Actual detailed results can be seen in the following paper:

Three-Dimensional Wind Measurements with the Fibered Airborne Coherent Doppler Wind Lidar LIVE

Results with a 2m length of IXF-2CF-EY-PM-30-300 and 16 Watt of launched power:

  • M²= 1,1
  • 715 ns pulses with 14 kHz repetition ferquency, pulse energy of 410 μJ

Such a set up allowed windspeed measurement reach up to 16km.

IXF-2CF-EY-PM-30-300
Core Diameter 30 µm
Cladding Diameter 300 µm
NA 0.09
Clad Absorption >2.8 dB/m @915nm
Clad Absorption >11.0dB/m @976nm
Core Absorption >70 dB/m @1536nm

Matching passive fibers

PM large core single clad fiber

IXF-PAS-PM-30-300-0.08_edA Preliminary

PM large core single clad fiber

IXF-2CF-PAS-PM-30-300-0.08_edA double clad passive pm fiber

Products

Product Specification Datasheet
Er/Yb Doped Fibers
IXF-2CF-EY-PM-12-130-L2 12 µm core diameter
55 dB/m absorption at 1536 nm
PDF More info
IXF-2CF-EY-PM-12-130-L3 12 µm core diameter
70 dB/m absorption at 1536 nm
PDF More info
IXF-2CF-EY-PM-12-130-0.10 12 µm core diameter
65 dB/m absorption at 1536 nm
PDF More info
IXF-2CF-EY-PM-25-250 25 µm core diameter PDF More info
IXF-2CF-EY-PM-30-300 30 µm core diameter PDF More info
IXF-2CF-AG-EY-O-5-105-125-HTC 5 µm core diameter
All Glass
High Temperature Coating
More info
IXF-2CF-AG-EY-O-9-105-125-HTC 8.5 µm core diameter
All Glass
High Temperature Coating
More info
Er Doped Fibers
IXF-EDF-FGL-PM-L1 C & L Band
18 dB/m absorption at 1530 nm
More info
IXF-EDF-FGL-PM-L2 C & L Band
24 dB/m absorption at 1530 nm
More info
IXF-EDF-FGL-PM-L3 C & L Band
30 dB/m absorption at 1530 nm
More info

PUBLICATIONS

  • High Peak Power Single-Frequency Amplifier based on a Er-Yb Doped Polarization Maintaining LMA Fiber

    A. Durécu, P. Bourdon, F. Gustave, H. Jacqmin, J. Le Gouët & L. Lombard (ONERA)

    Conference on Lasers and Electro-Optics (CLEO), May 2018

    We report on single-frequency all-fiber amplifiers based on PM Er-Yb doped P2O5-Al2O3-SiO2 fibers. Peak power up to 700W at 1545nm for 730ns pulse duration has been obtained with a good beam quality and a 17dB PER was measured.

    Learn more
  • High peak power single-frequency MOPFA for lidar applications

    A. Durécu, P. Bourdon, F. Gustave, H. Jacqmin, J. Le Gouët & L. Lombard (ONERA)

    HAL archives ouvertes, hal-01354707, 19 August 2016

    Long range coherent detection wind lidars have many applications in the fields of wind farms and aircraft safety. Fiber laser sources emitting around 1.5 µm show key advantages such as versatility, modularity and obustness of alignments to vibrations. However, nonlinear effects such as Stimulated-Brillouin-Scattering limit achievable peak power because of strong fiber core confinement.

    Download
  • High Peak Power Single-Frequency Efficient Erbium- Ytterbium Doped LMA Fiber

    W. Renard, J. Le Gouët, L. Lombard, A. Durecu, P. Bourdon, G. Canat (ONERA); T. Robin, B. Cadier (iXblue)

    Conference on Lasers and Electro-Optics (CLEO), May 2015

    We report on single-frequency all-fiber amplifiers based on Er-Yb doped P2O5-Al2O3- SiO2 fibers. Peak power up to 1120 W at 1545 nm for 108 ns pulse duration has been obtained with 18 % slope-efficiency. Continuous-wave operation generated up to 14 W.

    Learn more