Table 1 Summary of different topological photonics platforms, and their key characteristics

Glass (borosilicate, fused silica)^{62,63,64,68,69,70,71}

Low, Δn ≈ 5 × 10⁻³−1 × 10⁻²¹⁰⁰, low birefringence

Probabilistic, four-wave mixing^70,101

1D and 2D^9,102

Slow, thermo-optic¹⁰³

0.18–3 μm¹⁰⁴

Polarization, time-bin, frequency-bin, path and OAM^105,106

III–V^24,44,107

Can be high, in suspended membranes Δn > 2.5¹⁰⁸, with high birefringence

Probabilistic through SPDC, on-demand using QDs¹⁰⁹

1D and 2D^110,111,112

Fast EO modulation, MEMS¹¹³

GaAs 1–16 μm, check ref. ¹¹⁴ for GaP, InP, InAs, and InSb

Time-bin, frequency-bin, path

Silicon-based (Si, SiN, SiC)^{10,43,115,116}

High, Δn ≈ 2¹⁰, high birefringence

Probabilistic four-wave mixing, on-demand defects^65,117,

1D and 2D^{10,35,65,67,115}

Thermo-optic, carrier-induced dispersion (Si), MEMS, phase change materials^{118,119,120,121,122}

Si 1.1–8 μm, SiN 0.40–2.235 μm and SiC 0.37–5.6 μm^{123,124,125,126}

Time-bin, frequency-bin, path, and transverse mode^127,128

Lithium niobate¹²⁹

High in thin-film LNOI (high birefringence), low in diffusion-based waveguides (low birefringence)¹³⁰

Probabilistic SPDC, on-demand through hybrid integration^131,132

1D and 2D¹²⁹

Fast EO modulation¹³³

0.4–5.2 μm¹³⁴

Time-bin, frequency-bin, path