A monolithically integrated silicon coherent receiver based on a novel scheme with a crossing-free 90Â° hybrid optical coupler and two balanced germanium photodetectors is reported. The integrated receiver is compact (footprint is 0.8Ã 1.0mm<sup>2</sup>), 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<sup>-4</sup> for an optical signal-to-noise ratio (OSNR) lower than 17 dB, whereas 16-QAM at 20 Gbaud shows a BER not better than 3<sup>â</sup>10<sup>-2</sup> because of the nonideal behavior of the device. Reasons for the performance limitations are discussed.
|Titolo:||A compact silicon coherent receiver without waveguide crossing|
|Data di pubblicazione:||2015|
|Appare nelle tipologie:||1.1 Articolo su Rivista/Article|