Chalcogenide MWIR Fused Fiber Combiner

Fiber optic combiners are used to combine two or more fibers into one common aperture. The signals from several sources are combined into one fused fiber, thereby combining their output powers and wavelengths.

Inspired by silica fiber power combiners in Near-IR used to combine power for pumping double clad fiber lasers and incoherent beam combining of high power lasers, IRflex’s proprietary manufacturing technology of chalcogenide glass Mid-IR fibers makes it possible to extend the power combining capacity beyond 2µm silica fiber wavelength range.

Chalcogenide glass is made from a mixture of the chalcogenide elements: sulfur, selenium and tellurium. It offers promising properties such as transmission in mid and far infrared regions of spectra, lower values of phonon energies, high refractive index and very large nonlinearities as compared to silica. Chalcogenide glass fibers are the ideal candidates to manufacture the mid-wave infrared fiber combiner. The fiber transmits Mid-IR wavelengths from 1.5 to 6.5µm with typical fiber loss of 0.1dB/m.

Using IRflex’s arsenic sulfide glass fibers, IRflex’s multimode Mid-IR fused fiber combiners can incoherently combine the power from multiple laser sources into a common output aperture.   These combiners can also spectrally combine laser sources that cover the MWIR spectrum from 1.5 to 6.5µm.


Fused Fiber Combiner Concept

3 to 1 combiner

Key Features:

  • High port transmission and combining efficiency for MWIR spectral beam combining up to 98%
  • Independent wavelength transmission from 1.5 to 6.5µm wavelength range
  • High power handling strength with mechanical flexibility
  • Custom configurations availability


  • Power and wavelength combining of IR diodes and quantum cascade lasers for high power laser systems.
  • Remote sensing
  • Long-range target identification and LIDAR
  • Gaseous leaking detection, mineral and petroleum prospecting
  • Medical surgery


Models Ports Operation Wavelength Input Fiber Output Aperture Port Transmission Efficiency
MWIR-FC-3 3 to 1 1.5 to 6.5μm
100μm core diameter, NA=0.3 100μm diameter, NA=0.3 75 to 98%*
MWIR-FC-7 7 to 1 1.5 to 6.5μm
50μm core diameter, NA=0.20 100μm diameter, NA=0.20 75 to 98%*

* The combined input power should not exceed 5 Watts.  For higher input power, please contact IRflex.

The input fiber connector types include FC/APC, FC/UPC, SMA or IRflex’s FC/B® - the FC connector at Brewster Angle that enables perfect coupling without reflection with polarized laser beam. The standard output fiber connector is SMA connector.

Due to chalcogenide glass’ high refractive index (n=2.4), approximately 17% of the light will be reflected at each interface, which results in a total transmission of 69% of the incident light. To meet optimum transmission requirements, the fiber end faces may need to have AR coatings to increase the throughput of the system and reduce hazards caused by reflections traveling backwards through the system (ghost images). AR coating is also very durable, with resistance to both physical and environmental damage.

IRflex offers Anti-reflection coating, broadband or at a specific wavelength, to any flat input and output fiber connector of the MWIR Fused Fiber Combiner as an option.

When specifying an AR coating to suit your specific application, please be fully aware of the full spectral range of your system.  While an AR coating can significantly improve the performance of an optical system, using the coating at wavelengths outside the designed wavelength range could potentially decrease the performance of the system.