Large and tunable optoelectronic chromatic dispersion in PIN-type photodiodes.

It is known that PN-type photodiodes possess high optoelectronic chromatic dispersion (OED). Here we present a theoretical and experimental study of OED in PIN-type photodiodes. Applying the modulation phase-shift technique, a Ge PIN photodiode exhibits ∼0.

Multitasking FBG sensors for condition monitoring with a wideband (DC-MHz) interrogation system.

We demonstrate diagnosis of several machine-condition failures using wide-frequency-band interrogation of fiber Bragg grating (FBG) sensors. In collaboration with Israel's national water company Mekorot Ltd., a scaled-down version of a semi-submerged pumping system was constructed.

Spectral sensor of the ethanol concentration in water based on photodiode optoelectronic chromatic dispersion.

Optoelectronic chromatic dispersion (OED) of a PN-type germanium photodiode is used for spectral sensing of ethanol concentration in water. A concentration sensitivity of 70 ppm is achieved. Spectral sensors based on OED in PN-type photodiodes can serve as low-cost on-chip devices for optical spectroscopy.

Femtometer-resolved wavelength monitor based on photodiode optoelectronic chromatic dispersion with RF phase-shift amplification.

The spectral sensitivity of photodiode-based optoelectronic chromatic dispersion is enhanced by phase-shift amplification using RF interferometry. With phase-shift amplification of =4⋅10, a peak phase-shift sensitivity of Δθ = 27 deg/pm is achieved, corresponding to a spectral resolution of Δλ = 1 fm. This all-electronic solid-state technology can serve as an on-chip inexpensive technique for femtometer-resolved wavelength monitoring.

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

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.

Optoelectronic chromatic dispersion and wavelength monitoring in a photodiode.

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 αdα/dλ .

Heterodyne phase-shift-amplified interferometry with improved shot-noise-limited sensitivity and immunity to RIN.

Phase-shift-amplified interferometry (PAI) is demonstrated using a heterodyne detection scheme. We demonstrate a sensitivity amplification factor of 35, giving $7.9 \cdot {10^{ - 4}}$7.

Phase-shift-amplified interferometry.

We present a new technique for improving the sensitivity of an interferometer, phase-shift-amplified interferometry (PAI), which is based on two embedded interferometers. The internal interferometer, which is biased in anti-phase, amplifies the phase shift; the external interferometer converts this into an amplified intensity shift. PAI can improve the sensitivity of standard interferometers by an order of magnitude or more.

Detuned Brillouin amplification of OTDR signals with an enhanced signal-to-noise ratio.

The technique known as external Brillouin amplification of Rayleigh scattering is characterized in the detuning regime. When employed as an amplifier of OTDR signals, it is shown that the signal-to-noise ratio is significantly improved for optimum pump Stokes detuning, leading to enhanced nanostrain sensitivity. This effect is due to the Brillouin bandwidth dependence on the Stokes power.