Electrical spectrum synthesis technique using digital pre‐processing and ultra‐broadband electrical bandwidth doubler for high‐speed optical transmitter

Proposed is an electrical spectrum synthesis technique that converts low-speed signals to a high-speed signal using transmitter-side digital signal processing (DSP) and an ultra-broadband electrical bandwidth doubler. The transmitter-side DSP converts a high-speed signal to low-speed upper and lower sideband signals, down- and up-converts the low-speed signals into baseband signals, and adds and subtracts the in-phase and the quadrature components of the baseband signals. The digital pre-processed low-speed signals output from digital-to-analogue converters are multiplexed to the high-speed signal by the bandwidth doubler, which consists of analogue multiplexers designed and fabricated using in-house indium phosphide heterojunction bipolar transistor technologies. A 120 GBaud quadrature phase shift keying signal has been successfully generated by using the proposed technique as a demonstration of a high-speed optical transmitter.

[1]  Munehiko Nagatani,et al.  160-Gbps Nyquist PAM4 transmitter using a digital-preprocessed analog-multiplexed DAC , 2015, 2015 European Conference on Optical Communication (ECOC).

[2]  H. Yamazaki,et al.  A 50-GHz-bandwidth InP-HBT analog-MUX module for high-symbol-rate optical communications systems , 2016, 2016 IEEE MTT-S International Microwave Symposium (IMS).

[3]  H. Nosaka,et al.  A 128-GS/s 63-GHz-bandwidth InP-HBT-based analog-MUX module for ultra-broadband D/A conversion subsystem , 2017, 2017 IEEE MTT-S International Microwave Symposium (IMS).

[4]  Munehiko Nagatani,et al.  Digital-Preprocessed Analog-Multiplexed DAC for Ultrawideband Multilevel Transmitter , 2016, Journal of Lightwave Technology.

[5]  S. Chandrasekhar,et al.  180-GBaud All-ETDM Single-Carrier Polarization Multiplexed QPSK Transmission over 4480 km , 2018, 2018 Optical Fiber Communications Conference and Exposition (OFC).