Fabrication of Periodically-Inverted AlGaAs Waveguides for Quasi-Phase-Matched Wavelength Conversion at 1.55 µm

Abstract

We have improved fabrication processes of periodically inverted AlGaAs waveguides for highly efficient quasi-phase-matched wavelength conversion. In order to reduce propagation losses in waveguiding devices fabricated based on sublattice reversal epitaxy, we have introduced template planarization by chemical mechanical polishing and low-temperature regrowth technique. Corrugations at the core/ clad interface and the propagation loss at 1.55 mm has been reduced to 40 nm and 9 dB/cm, respectively. First-order quasi-phase-matched second-harmonic generation was demonstrated at 1.55 mm fundamental wavelength with a 1.47-mm-long device. Obtained internal conversion efficiency is 2.2%/W which is one order of magnitude lower than the theoretical value for an ideal lossless waveguide. A significant increase in the conversion efficiency is expected with a redesign of the device and further optimization of the fabrication processes. #

Recent advances in phase matching of second‐order nonlinearities in monolithic semiconductor waveguides

“…Also, any misalignment of the core layer in the regrown material can lead to mode profile oscillations and the formation of an effective index grating. Progress has been made recently to reduce the scattering loss by reducing the corrugations of the domains resulting from original template and regrowth processes [37][38][39]. Minimum losses of 4.5 dB cm 1 at 1.55 μm and 9.7 dB cm 1 at the secondharmonic wavelength were obtained, and the highest internal conversion efficiency of 43% W 1 was achieved in an 8 mm long waveguide under continuous-wave operation [38,39].…”

Sublattice reversal in GaAs/Ge/GaAs (113)B heterostructures and its application to THz emitting devices based on a coupled multilayer cavity

“…25,26) This novel growth technique has also been applied to several nonlinear optical devices grown on lowindex GaAs substrates. [27][28][29] As far as we know, however, there has been no report on the experimental study of sublattice reversal on high-index GaAs substrates.…”

Hyperentangled photon sources in semiconductor waveguides

“…These structures can be integrated with both active and passive photonic components. Various strategies have been developed to achieve phase matching (PM) in AlGaAs waveguides [14,15]: QPM [16][17][18], form birefringence [19,20], modal phase matching (MPM) [21], counterpropagating modes [22], and the use of Bragg reflection waveguides (BRWs) [23,24]. Techniques to generate polarization entangled photons in AlGaAs waveguides have been theoretically developed [25][26][27] as well as experimentally demonstrated [22,28,29].…”