Exail header laser lidar

Light Detection And Ranging

LIDAR

Exail can deliver a wide range of optical components for the design of high-power laser sources (in pulsed regime) for lidar applications: windmills for wind speed measurements, autonomous vehicles for the mapping of their environment, and even lidars in space.

Lithium niobate (LiNbO 3) phase and intensity modulators and the latest generation of Er/Yb doped fibers are particularly optimized to enable higher efficiency with lidar laser sources. On the detection side, Exail customized micro-optical benches can be useful whether the lidar systems rely on “time-of-flight” measurement with scan capability (distance measurement) or is dedicated to measure wind speed.

Typical LIDAR setups are based on Time of Flight (TOF) measurement

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.



Exail schema lidar setup
Exail schema lidar setup

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.



Exail schema coherently combined pulsed amplifier setup
Exail schema coherently combined pulsed amplifier setup

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.

Exail 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: https://www.mdpi.com/2073-4433/10/9/549

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 frequency, pulse energy of 410 μJ
  • Such a set up allowed windspeed measurement reach up to 16km.

Dedicated products

Exail bobine detouree

Product Name

IXF-2CF-EY-PM-30-300

Core Diameter

Core Diameter

Cladding Diameter

300 µm

NA

0.09

Clad Absorption

>2.8 dB/m @915nm

Clad Absorption

>11.0dB/m @976nm

Clad Absorption

>70 dB/m @1536nm

Matching passive fibers

Other references of optical fibers

    • Er/Yb Doped Fibers

IXF-2CF-EY-PM-12-130-L2

12 µm core diameter

55 dB/m absorption at 1536 nm

IXF-2CF-EY-PM-12-130-L3

12 µm core diameter

70 dB/m absorption at 1536 nm

IXF-2CF-EY-PM-12-130-0.10

12 µm core diameter

65 dB/m absorption at 1536 nm

IXF-2CF-EY-PM-25-250-AF

25 µm core diameter

IXF-2CF-EY-PM-30-300

30 µm core diameter

IXF-2CF-AG-EY-O-5-105-125-HTC-VU

5 µm core diameter

All Glass High Temperature Coating

IXF-2CF-AG-EY-O-9-105-125-HTC

8.5 µm core diameter

All Glass High Temperature Coating

IXF-2CF-AG-EY-PM-12-105-125-HTC

12 µm core diameter

All Glass High Temperature Coating

  • Er Doped Fibers
  • IXF-EDF-FGL-PM-L1

    C & L Band

    18 dB/m absorption at 1530 nm

    IXF-EDF-FGL-PM-L2

    C & L Band

    24 dB/m absorption at 1530 nm

    IXF-EDF-FGL-PM-L3

    C & L Band

    30 dB/m absorption at 1530 nm

  • Latest Er/Yb Doped Fibers
  • IXF-2CF-EY-O-10-130-010-HPA-LL

    10 µm core diameter
    0.10 core NA

    High Power Amplifier

    IXF-2CF-EY-O-13-130-009-HPA

    13 µm core diameter
    0.085 core NA

    High Power Amplifier

    Lithium Niobate (LiNbO 3) phase
    & intensity modulators

    Exail produit mpx2000 ln 01
    Exail micro optics assembly

    Integrated micro-optics assembly

    Publications