The characteristics of tapered lens fibers (TLFs) are analyzed by using a finite-difference time-domain (FDTD) method. Two types of TLFs are considered, namely, a tapered-cladding TLF and a tapered-core TLF. The radial FDTD method is first used to simulate light focusing for these two types of TLFs. It is shown that the tapered-core TLF has a smaller focus spot size and a larger transmission loss than the tapered-cladding TLF. The butt-coupling between a TLF of either type and a Si rib waveguide is then simulated by a three-dimensional FDTD method. The tapered-core TLF has a smaller coupling loss to the Si rib waveguide but a similar total loss (the sum of the coupling loss and the transmission loss), as compared with the tapered-cladding TLF.
© 2009 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: May 30, 2008
Revised Manuscript: December 9, 2008
Manuscript Accepted: December 12, 2008
Published: January 21, 2009
Liu Yang, Daoxin Dai, Bo Yang, Zhen Sheng, and Sailing He, "Characteristic analysis of tapered lens fibers for light focusing and butt-coupling to a silicon rib waveguide," Appl. Opt. 48, 672-678 (2009)