Broadband mid-IR chalcogenide fiber couplers

Area of Science:

• Materials Science
• Optical Engineering
• Photonics

Background:

• Mid-infrared (MIR) spectroscopy and sensing require robust optical components.
• Arsenic trisulfide (As2S3) glass offers excellent transmission in the MIR region.
• Fiber couplers are essential for manipulating light in optical systems.

Purpose of the Study:

• To demonstrate a broadband As2S3-based fiber coupler for operation up to 5.4 μm.
• To characterize the performance of the fabricated fiber coupler.
• To optimize coupler design through numerical analysis.

Main Methods:

• Fused biconical tapering technique for fiber coupler fabrication.
• Real-time monitoring of coupling ratio at 2.64 μm during manufacturing.
• Measurement of excess loss in the 5-5.4 μm wavelength range.
• Numerical analysis of fiber bend loss for design optimization.

Main Results:

• A broadband As2S3 fiber coupler operating up to 5.4 μm was successfully fabricated.
• Minimal excess loss was measured to be less than 1 dB in the 5-5.4 μm range.
• Optimal geometric parameters for the coupler were determined via numerical analysis of bend loss.

Conclusions:

• The developed As2S3 fiber coupler is suitable for broadband applications in the mid-infrared spectrum.
• The fused biconical tapering technique is effective for fabricating high-performance MIR fiber couplers.
• Numerical analysis aids in optimizing coupler design for minimal loss and enhanced performance.