Table 2.

Device operation with sub-1 V driving electronics without driving amplifier

	(a) QPKS 100 GBd	(b) 16QAM 50 GBd	(c) QPSK 50 GBd	(d) QPSK 25 GBd
Line rate	200 Gbit s−1	200 Gbit s−1	100 Gbit s−1	50 Gbit s−1
Const diagr.
BER	1.4 × 10−3	2.0 × 10−2	2.0 × 10−4	2.0 × 10−3
U meas50Ω,pp	426 mV	567 mV	326 mV	145 mV
E bit	0.61 fJ bit−1	0.30 fJ bit−1	0.36 fJ bit−1	0.07 fJ bit−1

Constellation diagrams and sub-fJ bit⁻¹ electrical energy consumptions at (a) 100 GBd, (b, c) 50 GBd, and at (d) 25 GBd