Reduced coupling loss using a tapered-rib adiabatic-following fiber coupler

• Published in: IEEE photonics technology letters Vol. 8; no. 8; pp. 1052 - 1054
• Main Authors: Smith, R.E., Sullivan, C.T., Vawter, G.A., Hadley, G.R., Wendt, J.R., Snipes, M.B., Klem, J.F.
• Format: Journal Article
• Language: English
• Published: IEEE 01.08.1996
• Subjects: Impedance; Optical coupling; Optical design; Optical fiber couplers; Optical fiber devices; Optical fiber losses; Optical fibers; Optical waveguides; Semiconductor device packaging; Semiconductor waveguides
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/68.508735

We present the design and experimental demonstration of a tapered-rib adiabatic-following fiber coupler (TRAFFIC). This device is an adaptation of a Shani-Henry mode converter fabricated in (Al)GaAs and designed to increase the coupling efficiency of conventional optical fibers to tightly-confined semiconductor rib waveguide devices. This approach offers the potential of significantly reducing fiber butt coupling losses from the typical values of 7 to 10 dB to values of <1 dB. This long-standing packaging problem is one of the major impediments to the widespread acceptance of semiconductor-based optoelectronics. Moreover, the design can be implemented with minimal increase in fabrication complexity since it uses only a straightforward modification to epitaxial growth, and one additional lithography and etching step.