The in-line laser speckle reducer (fiber optical beam homogenizer, or De-Speckler) is an all-fiber passive component which can efficiently homogenize speckle pattern and reduce unwanted modal noise (striations, hot spots, and beam non-uniformity) within a multimode optical fiber, producing a stable output beam that has fewer speckle hot spots and more uniform energy intensity profile. Lfiber’s in-line fiber optical speckle reducer (laser beam homogenizer) also mix light, which simplifies the combination of sources. They break up the input beam into smaller beamlets and reconfigure the modes of light. As a result, the input signals are mixed and the output signals are more uniform. The fiber optical speckle reducers offer superior optical transmission over a broad band, typically from 400 nm to 1800 nm. Multimode fibers with 105 μm, 200 μm, 300 μm, 400 μm, 600 μm, 800 μm core diameters are available.  Related Products

About Laser Speckle Patterns Exiting Multimode Optical Fibers

A speckle pattern is a spatial high-frequency random intensity pattern of energy produced by the mutual interference of a large number of coherent wavefronts. When light is transmitted in a multimode optical fiber, many modes of light exist with different optical phases. When observed at the end of the fiber, a laser speckle pattern exists as shown in Figure 1. Mode mixing will cause interference effects that alter the intensity and the form of the speckle pattern due to even very small perturbations to the fiber. The fiber is very sensitive to pressure, vibration, and motion changes.

Laser Speckle Pattern Speckle Noise in Multimode Optical Fiber Modal Noise

Figure 1.     Speckle pattern exiting fiber due to modal interference.

Speckle patterns are observed in the near field at multimode fiber (MMF) output facets. Figure 1 shows speckle patterns observed at the near field of a conventional MMF with a 650-nm laser.

About In-line Laser Speckle Reducer (De-Speckler, or Fiber Optical Beam Homogenizer)

Modal noise (“hot spot”) in an optical fiber is one of the most annoying problems in treating coherent light. It is important to stabilize the uniformity of the beam on-target so that output energy density and stability remain near constant. Because of the well-earned reputation of laser beams to change shape over time, some fiber optical beam homogenizers (laser speckle reducers, or De-Specklers) and beam-shaping devices have been developed in an effort to ensure a stable source for related applications.
The laser speckle reducers (in-line fiber optical beam homogenizer) help reduce sensitivity to variations in source properties, amplitude or phase, and provide a stable output beam. Lfiber’s in-line fiber optical beam homogenizers (laser speckle reducers) work on the simple principle. They break up the incident beam into smaller beamlets that are superimposed on top of one another, so that a loss of power density in one area of the input beam does not affect the stability/uniformity of the output beam. They can easily tolerate a range of input source conditions with minimal impact to the optical performance.


In-line Laser Speckle Reducer (Fiber Optical Beam Homogenizer)

In-line Laser Speckle Reducer Fiber Optical Beam Homogenizer
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  • High Transmission Efficiency
  • In-Line All-Fiber Structure
  • Small and Compact Designs
  • High Reliability and Stability


  • Reduce Laser Speckle Noise (Hot Spots)
  • Eliminate Striations and Beam Non-uniformity
  • Beam Homogenizing
  • Laser Material Processing


Intensity Profile of the Output Beams: WITHOUT V.S. WITH Laser Speckle Reducer


Without LFIBER Laser Speckle Reducer

In-line Laser Speckle Reducer Fiber Optical Beam Homogenizer
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Laser Speckle Reducer In-line Fiber Optical Beam Homogenizer
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With LFIBER Laser Speckle Reducer

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Laser Speckle Pattern Reducer Fiber Optical Laser Beam Homogenizers
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Laser Speckle Reducers In-Line Fiber Optic Beam Homogenizers


Specifications of Laser Speckle Reducer (Fiber Optical Beam Homogenizer)
Fiber Core/Cladding (μm)105/125, 200/220, 300/330, 400/440, 600/660
Numerical Aperture0.22
Operating Wavelength (nm)400-1800 nm
Transmission Efficiency≥90%
Input/output Fiber Pigtail Length (m)0.5, 1.0, 1.5, 2.0, etc.
Connector TypesSC/PC, FC/PC, ST, SMA905, etc.
Housing/Package TypeSteel tube, or box
Fiber Jacket/TubingBare fiber (without jacket), Φ900μm loose tube, Φ2.0mm or Φ3.0mm cable


  • For requests please specify the fiber core diameter, numerical aperture (NA), operating wavelengths, operating power, connector types, and input/output fiber pigtail length.
  • This laser speckle reducer (fiber optical beam homogenizer) is customizable and the above specifications are subject to change without notice.