Open AccessDemonstration of a 120° hybrid based simplified coherent receiver on SOI for high speed PON applications
Author(s) -
Md. Ghulam Saber,
Mohamed Osman,
David Patel,
Alireza Samani,
Eslam El-Fiky,
Md Samiul Alam,
Kh Arif Shahriar,
Zhenping Xing,
Maxime Jacques,
Boris Dortschy,
Gemma Vall-llosera,
Patryk J. Urban,
Fabio Cavaliere,
Stéphane Lessard,
David V. Plant
Publication year - 2018
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.26.031222
Subject(s) - optics , physics , transmitter , local oscillator , intensity modulation , phase noise , telecommunications , computer science , phase modulation , channel (broadcasting)
We demonstrate the first simplified coherent receiver using a 120° hybrid on silicon-on-insulator (SOI) for high speed PON applications. This coherent receiver integrates an inverse taper edge coupler for the received signal, a vertical grating coupler for the local oscillator input, a polarization splitter and rotator (PSR), a 120° hybrid based on a 3×3 multimode interference (MMI) coupler, and three germanium photodetectors. We achieved 25 Gbit/s two-level pulse amplitude modulation (PAM-2) transmission over 30 km standard single mode fiber (SMF) in the C-band without any digital signal processing (DSP) (e.g., pre-emphasis, pulse shaping, equalization, nonlinearity compensation) and dispersion compensation (e.g., optical or digital) either at the transmitter or at the receiver. The requirements for frequency and phase locking of the local oscillator (LO) were avoided due to the use of intensity modulated signals. Receiver sensitivities of -23.70 dBm, -20.30 dBm, and -15.10 dBm are achieved at a bit error rate (BER) below the hard-decision forward error correction (HD-FEC) threshold (i.e., 3.8 × 10 -3 ) in back-to-back (B2B), after 21 km and 30 km, respectively. We also demonstrate 25 Gbit/s PAM-4 transmission achieving receiver sensitivities of -15.30 dBm, -13.90 dBm, and -9.50 dBm below the HD-FEC threshold in B2B, after 10.5 km and 21 km, respectively.