Optoelectronic chromatic dispersion in germanium PN photodiodes: wavelength monitoring and FBG interrogation

Abstract

Optoelectronic chromatic dispersion (OED) has recently been shown to be a significant source of chromatic dispersion in photodiodes. We characterize the OED in a commercial germanium PN-type photodiode and determine the optimum conditions for maximum OED sensitivity and wavelength monitoring. A peak OED sensitivity of 1 deg/nm is measured in a spectral range of 1550–1558 nm with 4 MHz modulation. We also demonstrate an application of OED in fiber Bragg grating (FBG) interrogation. Quasi-static and vibration strains are monitored, with a spectral and strain sensitivity of 1 .25 p m / H z and 1 .08 µ ε / H z , respectively. Photodiode OED can form the basis of inexpensive chip-scale grating-less spectral analysis.

Optoelectronic oscillator controlled by photodiode-based optoelectronic chromatic dispersion and FBG integration

“…For example, with a 4 MHz sinusoidal illumination, a commercial Ge PN photodiode (GPD Optoelectronics, GM3) exhibits a wavelength-dependent RF phase-change of 1 𝑑𝑒𝑔/𝑛𝑚 in the telecommunication C-band. To achieve comparable dispersion in SMF28 optical fiber would require 400 𝑘𝑚 in length [2]. As a result, PN photodiodes have potential in high-sensitivity wavelength monitoring and spectral sensing.…”