title: Optimization of compact lateral, vertical, and combined tapered spot-size converters by use of the beam-propagation method.
abstract: A study of lateral, vertical, and combined spot-size converters is presented that employs full-vectorial numerical techniques such as modal solution and beam propagation based on the finite-element method. Spot-size expansion, coupling efficiency to an optical fiber, the mode-beating phenomenon, and transmission losses are demonstrated for all three spot-size-converter designs. Optimization of the device fabrication parameters is also reported. A significant improvement in the coupling efficiency and reduction of the device length are achieved when the length and the width are changed simultaneously.
authors.affiliation: Photonics Group, Department of Electronics, University of Kent, Canterbury CT2 7NT, UK. S.Haxha@kent.ac.uk
authors.forename: Shyqyri
authors.initials: S
authors.lastname: Haxha
authors.forename: Emmanuel O
authors.initials: EO
authors.lastname: Ladely
authors.forename: Fathi
authors.initials: F
authors.lastname: AbdelMalek
authors.forename: B M Azizur
authors.initials: BM
authors.lastname: Rahman