Efficient second harmonic generation in nanophotonic GaAs-on-insulator waveguides

Abstract

Nonlinear frequency conversion plays a crucial role in advancing the functionality of next-generation optical systems. Portable metrology references and quantum networks will demand highly efficient second-order nonlinear devices, and the intense nonlinear interactions of nanophotonic waveguides can be leveraged to meet these requirements. Here we demonstrate second harmonic generation (SHG) in GaAs-on-insulator waveguides with unprecedented efficiency of 40 W −1 for a single-pass device. This result is achieved by minimizing the propagation loss and optimizing phase-matching. We investigate surface-state absorption and design the waveguide geometry for modal phase-matching with tolerance to fabrication variation. A 2.0 µm pump is converted to a 1.0 µm signal in a length of 2.9 mm with a wide signal bandwidth of 148 GHz. Tunable and efficient operation is demonstrated over a temperature range of 45 ℃ with a slope of 0.24 nm/℃. Wafer-bonding between GaAs and SiO 2 is optimized to minimize waveguide loss, and the devices are fabricated on 76 mm wafers with high uniformity. We expect this device to enable fully integrated self-referenced frequency combs and high-rate entangled photon pair generation.

Efficient type II second harmonic generation in an indium gallium phosphide on insulator wire waveguide aligned with a crystallographic axis

“…Efficient type II second harmonic generation in an indium gallium phosphide on insulator wire waveguide aligned with a crystallographic axis N P , 1,2,3, * C M A , 1 C C , 4 S C , 5 A D R , 5 M H , 1 F R , 6,7 B K , 2,3 S -P G , 1 AND F L 1 Second harmonic generation (SHG) was first demonstrated almost 60 years ago [1] and still attracts a lot of attention. In particular, many novel integrated platforms for integrated SHG have recently emerged [2][3][4].…”

“…In particular, many novel integrated platforms for integrated SHG have recently emerged [2][3][4]. Conversions as high as 47,000%/(W • cm 2 ) have been demonstrated in III-V semiconductors [5], and ultra-wide tuning was recently shown in silicon waveguides [6]. The large intrinsic nonlinearity in addition to the high-index contrast of sub-wavelength structures leads to very large effective nonlinearities.…”

Second-harmonic generation enabled by longitudinal electric-field components in photonic wire waveguides

“…The high index contrast allows one to confine waves into subwavelength structures, greatly increasing the strength of light-matter interactions. Recent examples include ultraefficient second-harmonic (SH) generation [1][2][3] and frequency-comb formation [4,5]. The bound modes propagating in high-index-contrast waveguides are different from the well-known transverse plane-wave solutions of the Helmholtz equation [6].…”

Influence of longitudinal mode components on second harmonic generation in III-V-on-insulator nanowires

“…The large nonlinear coefficients as well as the high index contrast inherent to integrated photonics allows for strong nonlinear interaction at low power. Many instances of integrated second harmonics generation have been reported, with novel, low-loss, LiNbO 3 on insulator and III-V-on insulator platforms currently holding the record normalized conversion efficiency in nanowires [5][6][7]. In most theoretical analysis, the light is approximated by a purely transverse mode such that a single incoming polarization state and spatial profile is considered.…”

“…While we focus on III-V semiconductor wire waveguides [6,7,16], we stress that our analysis can be easily adapted to other platforms. We consider indium gallium phosphide (InGaP) around 1550 nm as the guiding material [8,17].…”