Efficient continuous wave second harmonic generation pumped at 1.55 µm in quasi-phase-matched AlGaAs waveguides

Abstract

We have fabricated quasi-phase-matched AlGaAs waveguides for continuous-wave second-harmonic generation (SHG) pumped around 1.55 microm. We find that the losses, which limit the conversion efficiency of this type of waveguide, are resulted from two corrugations--the initial template corrugation and the regrowth-induced domain-boundary corrugations. We are able to reduce the waveguide loss by improving the growth conditions. The waveguide loss is 6-7 dB/cm at 1.55 microm, measured using the Fabry-Perot method. A record internal SHG conversion efficiency of 23 %W-1 for AlGaAs waveguides is achieved using a 5-mm-long waveguide with a pump wavelength of 1.568 microm.

GaAs/AlOx Nonlinear Waveguides for Infrared Tunable Generation

“…This is the case of quasi phase www.intechopen.com matched AlGaAs waveguides, based on the same inversion technique of bulk orientationpatterned GaAs. The MBE growth of thin AlGaAs multilayers on GaAs/Ge templates has recently allowed the demonstration of guided-wave quasi phase matched frequency doubling (Yu et al, 2005). With a CW 1.55 µm pump, a normalized conversion efficiency norm = 92 % W -1 cm -2 was achieved, much lower than the calculated efficiency, norm =500% W -1 cm -2 .…”

Pulsed-squeezed-light generation in a waveguide with second-subharmonic generation and periodic corrugation

“…For this reason we need a tool that allows us to reach nonlinear phase matching conditions for an arbitrary photonic structure. Periodic poling [39][40][41][42] of χ (2) susceptibility has occurred to be extraordinarily useful here and has resulted in the so-called quasi-phase-matched nonlinear interactions. Using this method even spectrally broadband two-mode nonlinear interaction with femtosecond pulses has become possible [43].…”

Second Harmonic Generation in AlGaAs Nanowaveguides

“…However, this cannot be easily achieved in an arbitrary geometry due to the inherent material dispersion. For momentum conservation to be satisfied, bulk birefringent crystals (such as BBO and KTP) [2,3] as well as waveguide geometries (in polymers [4], LiNbO 3 [5,6], and semiconductors [7][8][9][10][11]) have been successfully used. The latter solution has recently gained a significant amount of scientific attention, resulting in the development and improvement of several phase-matching techniques in waveguiding structures.…”

“…Of particular importance for this paper, SHG has been previously realized in isotropic AlGaAs by way of modal phase-matching (MPM) [7,8], quasi-phase-matching (QPM) [8][9][10], or artificial birefringence [8,11]. Unfortunately, most of the proposed solutions require costly and complex fabrication procedures.…”

“…Unfortunately, most of the proposed solutions require costly and complex fabrication procedures. In particular, they include (i) the introduction of additional thin oxidized layers of Al (in the core region of the waveguides) in order to break the isotropy of GaAs and induce artificial birefringence [11]; (ii) periodic domain orientations or quantum well intermixing [8][9][10] for QPM; or (iii) multi--step etching of "M-shaped" waveguides for MPM [7,8]. In addition, even more advanced photonic structures in the form of the Bragg reflector waveguides [16], ring resonators [17], and waveguide couplers [18] suitable for SHG have also been investigated.…”