Relaxing alignment tolerance in single-mode fiber connections using 3D nanoprinted beam expanders

Optical fiber technology is the driving force behind the ever-increasing data transport and internet usage in today's connected society. The tight alignment tolerance required when connecting single-mode telecom fibers become even more tight when multiple fiber connectors are being used in the optical link. To alleviate this, we expand the mode field of the fiber and use 3D nanoprinting to print taper structures that can relax alignment tolerances in physical contact expanded beam connectors. We present the design and fabrication of a linear taper which expands the fundamental mode of a single-mode telecom fiber adiabatically with a factor of 3. The taper itself was fabricated on top of a cleaved fiber facet with the two-photon polymerization-based 3D nanoprinting technique, which allows fabrication of high aspect-ratio structures with submicrometer resolution. A proof-of-concept demonstrator was built to measure the obtained misalignment tolerance relaxation. Experimental results for lateral misalignment show excellent agreement with simulated values, but the beam expansion with an air-cladding taper also induces an excess loss of about 0.22 dB compared to a standard physical contact connection without beam expansion. This shows the compromise that has to be made between insertion loss and misalignment tolerance relaxation. The use of additive manufacturing techniques in fiber beam expansion applications makes it possible to fabricate taper structures with full 3D design freedom.

Trefwoorden:OPTICAL-FIBER; TAPERS; EXPANSION, Beam expansion, Misalignment tolerances, 3D nanoprinting, Adiabatic taper, Fiber connector, Two-photon polymerization, Direct laser writing, Fiber taper

Auteurs:International

Toegankelijkheid:Closed