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

• Published in: Electronics letters 2018-11, Vol.54 (24), p.1390-1391
• Main Authors: Hamaoka, F, Nakamura, M, Nagatani, M, Wakita, H, Yamazaki, H, Kobayashi, T, Nosaka, H, Miyamoto, Y
• Format: Article
• Language: English
• Subjects: analogue multiplexers; digital pre‐processed low‐speed signal output; digital signal processing chips; digital‐analogue conversion; digital‐to‐analogue converters; DSP; electrical spectrum synthesis technique; heterojunction bipolar transistors; high‐speed optical transmitter; III‐V semiconductors; indium compounds; InP; in‐house indium phosphide heterojunction bipolar transistor technologies; multiplexing; Optical communication; optical transmitters; phase shift keying; quadrature phase shift keying signal; transmitter‐side digital signal processing; ultrabroadband electrical bandwidth doubler
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2018.6216

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.