-40 -20 0 20 40 27 25 23 21 Gate Voltage (V) Frequency (MHz) -20 -5 10 25 33.0 32.5 32.0 31.5 Gate Voltage (V) Frequency (MHz) 33 32 31 30 29 Frequency (MHz) -40 -20 0 20 40  Gate Voltage (V) I -40 -20 0 20 40 33 31 29 27 Gate Voltage (V) Fr equ ency (MHz) ) b ) a ) d ) c FIG. 4: (color online) a) and b) Shows mode mixing for device-3 and device-1 respectively (for device-3, d=103 nm and l=3.1 µ m). c) Calculated dispersion for mode mixing using asymmetry in the wire. d) Zoomed-in view for device-1 (Fig.4b) which shows the mixing of the modes as a function of V DC g . Minimum separation between the modes, indicated by the double-headed arrow, is 0 . 25 ± 0 . 02 MHz. 15