InP-Based Monolithically Integrated Photonic Devices for Digital Coherent Transmission

• Published in: IEEE journal of selected topics in quantum electronics Vol. 24; no. 1; pp. 1 - 11
• Main Authors: Yagi, Hideki, Kaneko, Toshimitsu, Kono, Naoya, Yoneda, Yoshihiro, Uesaka, Katsumi, Ekawa, Mitsuru, Takechi, Masaru, Shoji, Hajime
• Format: Journal Article
• Language: English
• Published: IEEE 01.01.2018
• Subjects: Coherent transmission; Fiber lasers; Indium phosphide; integrated optoelectronics; Mach-Zehnder modulators; Modulation; multimode interference structure; Optical fiber devices; Optical waveguides; photodiodes; Power generation; Semiconductor optical amplifiers; tunable lasers
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2017.2725445

We comprehensively review InP-based monolithically integrated photonic devices for digital coherent transmission. A single-stripe tunable laser consisting of the tunable distributed amplification-chirped sampled grating-distributed reflector structure has yielded the high fiber output power of more than +17 dBm and the narrow spectral linewidth of less than 200 kHz, which achieved sufficient properties for 16-ary quadrature amplitude modulation (16QAM). A dual-polarization in-phase and quadrature modulator module with the Mach-Zehnder modulator array accomplished 16QAM modulation for 224 Gb/s at a low differential driving voltage of 2.5 V pp . A photodetector monolithically integrated with a 90° hybrid presented a high responsivity (> 0.130 A/W over C-band) and the stable operation with low dark current over 5000 h in the accelerated aging test (test condition: -7.5 V at 175 °C). Demodulation of 224 Gb/s DP-16QAM modulated signals was demonstrated as the compact coherent receiver using this photodetector. A wide 3-dB bandwidth of more than 40 GHz for 400 Gb/s DP-16QAM by 64 GBaud operation was also realized as the receiver thanks to p-i-n-photodiodes with a high-speed response.