Open AccessOptical 45° hybrid for demodulating 8-ary DPSK signal
Author(s) -
Seok−Hwan Jeong,
Ken Morito
Publication year - 2010
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.008482
Subject(s) - demodulation , optics , interferometry , physics , interference (communication) , differential phase , phase (matter) , signal (programming language) , phase modulation , computer science , telecommunications , phase noise , channel (broadcasting) , quantum mechanics , programming language
We propose a novel optical 45 degrees hybrid employing a 2 x 8 paired interference based multimode interference (MMI) coupler, three phase shifters and three 2 x 2 optical couplers. Since the proposed 45 degrees hybrid can demodulate an 8-ary differential phase shift keyed (8-DPSK) signal with only one delayed Mach-Zehnder interferometer (DMZI), the demodulator has simpler configuration and much smaller device dimensions than conventional 8-DPSK demodulators consisting of four pairs of DMZIs and 2 x 2 optical couplers. We calculate and experimentally demonstrate octagonal phase response of the proposed 45 degrees hybrid with a relative phase deviation of < +/- 5 degrees over 32-nm-wide spectral range.