The two-photon absorption semiconductor waveguide autocorrelator

Optical signal processing via two-photon absorption in a semiconductor microcavity for the next generation of high-speed optical communications network

“…where S is the illuminated area, hν is the photon energy, and I SPA abs and I TPA abs are the SPA and TPA contributions in the total absorption, respectively [13]. Therefore, to observe the TPA process, the semiconductor material is chosen, so that the band gap is greater than the energy of the incident photons but less than twice the photon energy.…”

Complete chirp analysis of a gain-switched pulse using an interferometric two-photon absorption autocorrelation

“…However, this method is complicated, sensitive to phase-matching conditions in a nonlinear crystal, and also requires relatively expensive components such as a monochrometer or a CCD array as well as a complicated algorithm to retrieve the frequency chirp information of a pulse. 9 In this paper, we use a fringe-resolved autocorrelator based on two-photon absorption (TPA) with a large bandgap semiconductor photodiode to avoid the phase-matching problem associated with a nonlinear optical crystal 9,10 and suggest a simple but accurate measurement method for the nonlinear frequency chirp of a gain-switched pulse. The pulse width and the frequency chirp information of a pulse were obtained with high precision from the intensity autocorrelation and the second-harmonic interferogram.…”

<title>Ultrafast harmonic mode-locking of monolithic compound-cavity laser diodes incorporating photonic-bandgap reflectors</title>

“…The use of two-photon absorption in a semiconductor waveguide as a nonlinear detection mechanism for autocorrelation measurements was reported in [19]. The advantages include high sensitivity and a broad wavelength range.…”