A Compact Silicon Coherent Receiver Without Waveguide Crossing

Author

Faralli, S. ; Meloni, G. ; Gambini, F. ; Klamkin, J. ; Poti, L. ; Contestabile, G.

Author_Institution

Scuola Superiore Sant´Anna, Pisa, Italy

Volume

7

Issue

4

fYear

2015

fDate

Aug. 2015

Firstpage

1

Lastpage

6

Abstract

A monolithically integrated silicon coherent receiver based on a novel scheme with a crossing-free 900 hybrid optical coupler and two balanced germanium photodetectors is reported. The integrated receiver is compact (footprint is 0.8 × 1.0 mm²), and it is demonstrated by working with single-polarization 56-Gb/s quadrature phase-shift keying (QPSK) and 80-Gb/s 16-quadrature amplitude modulation (16-QAM) signals. In particular, QPSK transmission that is back-to-back at 28 Gbaud shows a bit-error rate (BER) below 10^-4 for an optical signal-to-noise ratio (OSNR) lower than 17 dB, whereas 16QAM at 20 Gbaud shows a BER not better than 3*10^-2 because of the nonideal behavior of the device. Reasons for the performance limitations are discussed.

Keywords

elemental semiconductors; error statistics; germanium; integrated optics; optical couplers; optical receivers; photodetectors; quadrature amplitude modulation; quadrature phase shift keying; silicon; 16-quadrature amplitude modulation; Ge; QPSK transmission; Si; balanced germanium photodetectors; bit rate 80 Gbit/s; bit-error rate; compact silicon coherent receiver; crossing-free 900 hybrid optical coupler; monolithically integrated silicon coherent receiver; optical signal-to-noise ratio; single-polarization quadrature phase-shift keying; Bandwidth; Bit error rate; Couplers; Optical receivers; Optical waveguides; Silicon; Optical communications; coherent receivers; photonic integrated circuits (PICs); silicon photonics;

fLanguage

English

Journal_Title

Photonics Journal, IEEE

Publisher

ieee

ISSN

1943-0655

Type

jour

DOI

10.1109/JPHOT.2015.2456632

Filename

7159016