Open AccessPrinciples and application of reduced beat length in MMI couplers
Author(s) -
Lung-Wei Chung,
SanLiang Lee,
Yen-Juei Lin
Publication year - 2006
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.14.008753
Subject(s) - optics , phase difference , beat (acoustics) , wavelength , interference (communication) , beam splitter , physics , power dividers and directional couplers , coupled mode theory , phase (matter) , computer science , refractive index , telecommunications , laser , channel (broadcasting) , quantum mechanics
A unified method was proposed to reduce the beat length of a multimode interference (MMI) coupler. By properly adjusting the phase difference of the N-fold images, the mode evolution is changed to generate self-images at a much shorter distance. The effect of adjusting the phase difference can be regarded as dividing the original MMI coupler into multiple sub-MMI couplers. Such an effect can be applied for both symmetric- and paired-interference cases. We applied the principle to design compact optical splitters operating at dual wavelength bands. The simulation shows that excellent performance with reduced coupler length can be obtained for splitters operating at both 1.3 and 1.55 mum bands.