Optoelectronic chromatic dispersion and wavelength monitoring in a photodiode

• Published in: Optics express 2021-06, Vol.29 (13), p.19839-19852
• Main Authors: Glasser, Ziv, Dubey, Pawan Kumar, Dutta, Ayuushi, Liokumovitch, Egor, Abramov, Rita, Sternklar, Shmuel
• Format: Article
• Language: English
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.424157

The optoelectronic process of light absorption and current formation in photodiodes is shown to be a significant source of optoelectronic chromatic dispersion (OED). Simple design rules are developed for fabricating a photodiode-based dispersion device that possesses large, small, zero, and either positive or negative OED. The OED parameter is proportional to a spectrally-dependent absorption term α −1 dα / dλ . Silicon-based devices are predicted to display significant OED throughout the near IR, while Ge and InGaAs have high OED in the C- and L-bands and 1650 nm region, respectively. The OED of a commercial Ge PN photodiode is measured to be 3460 ps/nm at 1560 nm wavelength with 500 kHz modulation, demonstrating 8 pm spectral resolution with the phase-shift technique. Temperature-tuning of the OED in the Ge photodiode is also demonstrated. The ubiquitous photodiode is a tunable OED device, with applications in high-resolution optical spectroscopy and optical sensing.