title: Mode-evolution-based polarization rotator-splitter design via simple fabrication process.
abstract: A mode-evolution-based polarization rotator-splitter built on InP substrate is proposed by combining a mode converter and an adiabatic asymmetric Y-coupler. The mode converter, consisting of a bi-level taper and a width taper, effectively converts the fundamental TM mode into the second order TE mode without changing the polarization of the fundamental TE mode. The following adiabatic asymmetric Y-coupler splits the fundamental and the second order TE modes and also converts the second order TE mode into the fundamental TE mode. A shallow etched structure is proposed for the width taper to enhance the polarization conversion efficiency. The device has a total length of 1350 µm, a polarization extinction ratio over 25 dB and an insertion loss below 0.5 dB both for TE and TM modes, over the wavelength range from 1528 to 1612 nm covering all C + L band. Because the device is designed based on mode evolution principle, it has a large fabrication tolerance. The insertion loss remains below 1 dB and the polarization extinction ratio remains over 17 dB with respect to a width variation of +/- 0.12 µm at the wavelength of 1570 nm, or +/- 0.08 µm over the entire C + L band.
authors.affiliation: Mitsubishi Electric Research Laboratories, 201 Broadway, Cambridge, MA 02139, USA.
authors.forename: Wangqing
authors.initials: W
authors.lastname: Yuan
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kojima
authors.forename: Bingnan
authors.initials: B
authors.lastname: Wang
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Koike-Akino
authors.forename: Kieran
authors.initials: K
authors.lastname: Parsons
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nishikawa
authors.forename: Eiji
authors.initials: E
authors.lastname: Yagyu
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007204:Indium / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D012031:Refractometry / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D010720:Phosphines; D007204:Indium; C090882:indium phosphide