Mach-Zehnder Silicon Photonic Modulator Assisted by Phase-Shifted Bragg Gratings

• Published in: IEEE photonics technology letters Vol. 32; no. 8; p. 1
• Main Authors: Jafari, O., Shi, W., LaRochelle, S.
• Format: Journal Article
• Language: English
• Published: New York IEEE 15.04.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive optics; Bandwidth; Bandwidths; Bragg gratings; CMOS; Electro-optic modulators; Error correction; Mach-Zehnder interferometers; Modulation enhancement; Modulators; Operating temperature; Optical device fabrication; Optical modulation; Optical resonators; Phase modulation; Photonics; Resonators; Signal processing; Silicon; Silicon photonics
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2020.2978793

We experimentally demonstrate a silicon photonic Mach-Zehnder modulator (MZM) assisted by phase-shifted Bragg gratings. Coupled resonators are inserted in the Bragg grating structure to significantly enhance the phase modulation efficiency, while maintaining a wide optical bandwidth compared to other resonator-based modulators. Fabricated using a CMOS-compatible foundry process, the device achieved a small-signal Vπ× L of 0.18 V.cm, which is seven times lower than a conventional silicon MZM fabricated with the same process. The device has a compact footprint, with a length of only 162 μm, and shows a modulation bandwidth of 28 GHz at a reverse bias of 1 V. Non-return-to-zero modulation is demonstrated at 30 Gb/s with a bit-error-rate (BER) below the 7%-overhead forward error correction (FEC) threshold over a bandwidth of 3.5 nm. This bandwidth should translate into an operating temperature range greater than 40 °C.