AlGaAs Nonlinear Integrated Photonics

Abstract

Practical applications implementing integrated photonic circuits can benefit from nonlinear optical functionalities such as wavelength conversion, all-optical signal processing, and frequency-comb generation, among others. Numerous nonlinear waveguide platforms have been explored for these roles; the group of materials capable of combining both passive and active functionalities monolithically on the same chip is III–V semiconductors. AlGaAs is the most studied III–V nonlinear waveguide platform to date; it exhibits both second- and third-order optical nonlinearity and can be used for a wide range of integrated nonlinear photonic devices. In this review, we conduct an extensive overview of various AlGaAs nonlinear waveguide platforms and geometries, their nonlinear optical performances, as well as the measured values and wavelength dependencies of their effective nonlinear coefficients. Furthermore, we highlight the state-of-the-art achievements in the field, among which are efficient tunable wavelength converters, on-chip frequency-comb generation, and ultra-broadband on-chip supercontinuum generation. Moreover, we overview the applications in development where AlGaAs nonlinear functional devices aspire to be the game-changers. Among such applications, there is all-optical signal processing in optical communication networks and integrated quantum photonic circuits.

High-efficiency ultra-fast all-optical photonic crystal diode based on the lateral-coupled nonlinear elliptical defect

“…The AOD is based on the nonlinear Kerr effect that the spatial electric field strength (E 0 ) at the defect should be somewhat different when light is incident from different directions. According to the formula ∆n = n 2 I = χ (3) |E 0 | 2 /n 0 , where n 2 is the Kerr coefficient associated with χ (3) , χ (3) is the thirdorder nonlinear coefficient, and I is the intensity of light, [34] the difference in spatial electric field intensity would lead to a difference in refractive index (∆n). This, in turn, would cause the shift of the transmission peak along the long wavelength direction to be inconsistent.…”

An Introduction to Nonlinear Integrated Photonics Devices: Nonlinear Effects and Materials

“…Among the III–V integrated nonlinear photonic platforms considered to date, AlGaAs is the most studied waveguide platform [ 93 ]. AlGaAs has been termed “the silicon of nonlinear optics” for a number of reasons.…”

“…The advances in the fabrication process made it possible to minimize the propagation loss in AlGaAs waveguides, e.g., in the AlGaAs-on-insulator (AlGaAs-OI) material platform, down to values less than 1 dB/cm, not so different from those achievable in SOI waveguides [ 93 ]. To date, in AlGaAs waveguide platforms, second- and third-order nonlinear optical phenomena, such as SHG, SFG, DFG, spontaneous parametric down-conversion (SPDC), FWM, 2PA, SPM, XPM, spontaneous four-wave mixing (SFWM), spatial soliton formation, SRS, and supercontinuum generation (SCG), have been experimentally investigated.…”

An Introduction to Nonlinear Integrated Photonics: Structures and Devices

“…This has been a strong driving force stimulating development of nonlinear optical devices based on III–V semiconductors and addressing challenges associated with loss mitigation and nonlinearity enhancement in these platforms. The main III–V integrated nonlinear photonic platforms considered to date are GaAs [ 76 ] and its AlGaAs [ 120 ] derivative, InP and InGaAsP, III-nitrides AlN [ 121 , 122 ], and GaN [ 123 ], as well as GaP [ 124 ] and its ternary derivative InGaP. We note that AlN [ 121 , 122 ] shows optical properties similar to SiN (refractive index, transparency, and n 2 ) but also possesses second-order nonlinearity.…”

“…( g – i ) Multi-layer platform with multi-quantum-well waveguide, modulated-χ (2) waveguide, and Bragg-reflector waveguide, respectively. Reproduced from [ 120 ] under Creative Commons License.…”