Hollow/Air Core Fibre Coupler


Electronics - Lasers, Optics & Photonics
Electronics - Interconnects


A fibre optic coupler is a fiberized component used as an essential building block to a fibre-based optical system such as fibre laser, fibre resonator, fibre interferometer,  and fibre communication network. A conventional fibre coupler is composed of two solid fibres thermally fused side by side. Hence, its performance is limited by the solid core.

The technology offer is based on an air core fibre, a new type of fibre coupler which is not bounded by material limitations. It can be used in mid-IR or UV regions where the conventional fibre couplers cannot cover. In addition, the air core allows delivery of ultrafast lasers and power splitting. The air core fibre coupler can be used to build an all-fibre ultrafast mid-IR fibre laser cavity. The technology offer can be potentially applied for high-power laser material processing.


The air core coupler is based on anti-resonant fibre technology. Two air cores in the coupler behave as an individual anti-resonant fibre core. Hence, the anti-resonant features such as broad band transmission and low loss are intact in the air core coupler.

An entire transmission window is coupled between the two air cores. The operation spectral range can be customized by adjusting design parameters. The proprietary fibre structure allows customized designs to fulfil via conventional fibre fabrication processes. Furthermore, a coupling ratio is variable by applying mechanical strain. The air core coupler offers:

  • Air gap enabled optical power coupling
  • Variable coupling strength by mechanical tension
  • Air cores that can be customized for desired operation spectral windows
  • No optical limitation imposed by material properties
  • Design is compatible to glass or polymer materials.


  • Mechanically variable fibre coupler or splitter as an alternative to the conventional fixed ratio couplers or splitters
  • Applications in a mid-IR or UV laser cavity or resonator
  • An optical multiplexing device in the emerging air core fiber based network
  • Ultrafast laser power splitter/delivery
  •  Air core fibre based resonators
  •  Air core fibre based interferometers
  • Sensors utilising the variable coupling feature
  • Sensors utilising the air cores to be filled with functional materials, and with combination with the above


Customers can enjoy experiences with the first anti-resonant fibre coupler in constructing their optical system and all-fibre mid-IR ultrafast fibre lasers. 

In addition, we offer a variety specialty fibres for high power laser applications. Fabrication technology for large mode area Yb-doped and Tm-doped fibres are available for custom requirements.

Step-index fibre, photonic bandgap fibre, air core fibre, multi-core fibre, air core fibre coupler and customised fibres are available in-house.

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