Fig. 2: Beyond 100 Gbit/s phototunable silicon Valley-Hall photonic crystal THz waveguide. | Nature Communications

Fig. 2: Beyond 100 Gbit/s phototunable silicon Valley-Hall photonic crystal THz waveguide.

From: Phototunable chip-scale topological photonics: 160 Gbps waveguide and demultiplexer for THz 6G communication

Fig. 2

a Photonic band diagram calculated using COMSOL Multiphysics for Si-VPC chip with l1 and l2 equal to 0.70a and 0.30a respectively. Inset shows the variation in bandgap as a function of the difference in triangular hole size (Δl = l1 − l2). b Measured transmission from VPC-B chip at various photoexcitation pump power. Inset shows the optical image of the fabricated VPC-B chip where the blue region highlights the domain walls. The red dot represents the photoexcitation position at the domain wall. c Error vector magnitude (EVM) versus data rate for both the straight (VPC-S) and bend (VPC-B) VPC chips recorded at different modulation formats (QAM-16 and 32). All the measurements were compared with reference measurements (without the chip). The value of bit-error-rate (BER) corresponding to higher data rates are written with the corresponding data points. d BER versus relative power at the transmitter (Tx) recorded at 50 Gbit/s for the VPC-B chip. The black curve corresponds to the no pump (0 mW) case, while the blue curve was recorded with 8 mW photoexcitation.

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