high-speed waveform generator  (Arkeo Pharmaceuticals)

Journal: Nature Communications

Article Title: Heterogeneously integrated lithium tantalate-on-silicon nitride modulators for high-speed communications

doi: 10.1038/s41467-026-69769-3

Figure Lengend Snippet: a Optical micrograph of a fabricated 6.8 mm-long hybrid modulator. Insets: optical micrographs of the modulator’s underlying components, which include Y-splitters, a coplanar waveguide electrode, and tapered transitions between Si 3 N 4 waveguides and Si 3 N 4 -LiTaO 3 waveguides (LTOD) with a simulated 0.28 dB insertion loss. b False-colored scanning electron microscopy (SEM) image of the cross-section of a manufactured Si 3 N 4 -LiTaO 3 modulator. c Normalized transmission of a 6.8 mm-long push-pull MZM versus applied voltage. The inset diagram shows the high-speed electrode geometry with a 23 μm signal width and a 6 μm electrode gap. d Measured electro-optic response (electro-optic S 21 ) and microwave return loss (electrical reflection S 11 ), revealing a high 3-dB bandwidth near 100 GHz. e Output optical intensity of the modulator while biased at its working voltage, i.e., its quadrature point, over 1 h.

Article Snippet: We drive the MZM with electrical PAM4 signals that are synthesized by offline digital signal processing (Tx-DSP) based on pseudo-random bit sequences and root-raised cosine pulse-shaping filters , and that are converted to the analog domain using a high-speed arbitrary waveform generator (AWG, M8199B, Keysight Technologies Inc.).

Techniques: Electron Microscopy, Transmission Assay

Journal: Nature Communications

Article Title: Heterogeneously integrated lithium tantalate-on-silicon nitride modulators for high-speed communications

doi: 10.1038/s41467-026-69769-3

Figure Lengend Snippet: a Experimental setup. ECL External cavity laser, FPC Fiber polarization controller, AWG Arbitrary-waveform generator, Tx-DSP Transmitter-digital signal processing (offline), Amp RF amplifier, LTOD Si 3 N 4 -LiTaO 3 modulator, EDFA Erbium-doped fiber amplifier, BPF Bandpass filter, VOA Variable optical attenuator, PD Photodiode, RTO High-speed real-time oscilloscope (256 GSa/s, 105 GHz), Rx-DSP Receiver-digital signal processing (offline). b Measured pre-forward error correction bit error ratio (BER) versus symbol rate for PAM4 transmission, with horizontal dashed lines indicating the thresholds for soft-decision forward error correction with 15% and 25% coding overhead (15% SD-FEC, 25% SD-FEC) and for hard-decision FEC with 7% coding overhead (7% HD-FEC). The eye diagrams of two selected data points are shown in ( d , e ). c Achievable information rates (AIR, orange dashed line) and corresponding net data rates (NDR, solid brown line) of the IMDD measurements, showing that the highest achieved NDR is 333 Gbit/s using a PAM4 signals at a symbol rate of 192 GBd. Eye diagrams (left) at selected symbol rate of 160 GBd PAM4 ( d ) and 200 GBd PAM4 ( e ), labeled in ( b ), along with the associated histograms (right) of the reconstructed signal amplitudes in the center of the corresponding symbol slot.

Article Snippet: We drive the MZM with electrical PAM4 signals that are synthesized by offline digital signal processing (Tx-DSP) based on pseudo-random bit sequences and root-raised cosine pulse-shaping filters , and that are converted to the analog domain using a high-speed arbitrary waveform generator (AWG, M8199B, Keysight Technologies Inc.).

Techniques: Transmission Assay, Labeling

Journal: Nature Communications

Article Title: Heterogeneously integrated lithium tantalate-on-silicon nitride modulators for high-speed communications

doi: 10.1038/s41467-026-69769-3

Figure Lengend Snippet: a Optical micrograph of a 13.5 mm-long Si 3 N 4 -LiTaO 3 (LTOD) IQ modulator. The waveguides are highlighted in red for better visibility. b Schematics of the setup used for the coherent communications experiment. AWG Arbitrary-waveform generator, Amp. RF amplifier, Tx-DSP Transmitter-digital signal processing (offline), ECL External cavity laser, FPC Fiber polarization controller, EDFA Erbium-doped fiber amplifier, BPF Bandpass filter, TO-PS Thermo-optic phase shifter, ECL External-cavity laser, 90 ∘ OH 90 ∘ optical hybrid, BPD Balanced photodiode, RTO High-speed real-time oscilloscope (256 GSa/s, 105 GHz), Rx-DSP Receiver-digital signal processing (offline). c Measured pre-forward error correction bit error ratio (BER) versus symbol rate for QPSK (brown line) and 16-QAM (dark blue line) signals with horizontal dashed lines indicating the thresholds for soft-decision forward error correction having 15% and 25% coding overhead (15% SD-FEC, 25% SD-FEC) and for hard-decision FEC with 7% coding overhead (7% HD-FEC). The gray dashed line at the bottom indicates the detection limit, below which our experiment cannot reliably measure BER due to the limited length of the recorded signals (2 23 samples). This limit corresponds to 13 detected bit errors at a symbol rate of 160 GBd with QPSK signals during the recording period. The resulting BER falls within the 99% confidence interval, ranging from half to twice the measured BER . The constellation diagrams of three selected data points, and are shown in ( e – g ). d Achievable information rate (AIR, dashed lines) and corresponding net data rate (NDR, solid lines) versus symbol rate for QPSK (brown lines) and 16-QAM (dark blue lines) signals. Constellation diagrams for QPSK signals at symbol rates of 160 GBd ( e ) and 204 GBd ( f ), and for the 16-QAM signals at a symbol rate of 176 GBd ( g ). The corresponding data points are marked by red dashed circles in ( c ).

Article Snippet: We drive the MZM with electrical PAM4 signals that are synthesized by offline digital signal processing (Tx-DSP) based on pseudo-random bit sequences and root-raised cosine pulse-shaping filters , and that are converted to the analog domain using a high-speed arbitrary waveform generator (AWG, M8199B, Keysight Technologies Inc.).

Techniques: