Table 1.

A comparison of technologies for modulating SiN waveguides

Reference	Waveguide thickness [nm]	Optically broadband	Modulation frequency	Released	Wavelength	VπL [V ⋅ cm]	Vπ [V]	VπLα [V ⋅ dB]	Size
Hosseini60	25	Yes	DC-629 kHz	No	640 nm	12.5	12.5a	-	10 mm
Freedman31	300	Yes	2.31 GHz	Yes	730 nm	0.26	1.3b	-	2 mm
Jin28	175	No	DC-300 kHz	Yes	1550 nm	3.6	8	1.1	1.2 mm × 1.2 mmc
Wang30	175	No	DC-20 MHz	No	1550 nm	43	-	1.3	1.2 mm × 1.2 mm
Tian29	810	No	~3 GHz	Yes	1550 nm	-	-	-	200 μm × 200 μm
Dong61	300	Yes	DC-120 MHz	Yes	780 nm	100d	100d	39e	1.3 mm × 0.6 mm
This work	96.5	Yes	704 MHz	No	1550 nm	54.7	9	10.17	23 mm2

V_πL for our multi-pass devices is defined using the length of waveguide modulated by the acoustic wave (38 × 1.6 mm = 6.08 cm). Thus, our V_πL reflects a property of the waveguide cross section and can be used to compare various waveguide platforms. V_πLα uses the total spiral length of 26 cm as all 26 cm of the spiral contribute to insertion loss. See Supplementary Note 5 for further comments. Device size is estimated based on information available in the associated reference. Some devices^31,60 have negligible width. In this case, size is reported as a length.

^aCalculated using an active length of 10 mm.

^bCalculated from modulation length and V_πL.

^cEstimated based on the ring resonator radius using single stripe waveguides.

^dPer phase shifter (i.e., it is not configured as push-pull) at room temperature.

^eCalculated using V_πL and a waveguide propagation loss of 0.39 dB cm⁻¹.