In practice, QKD is achieved with optical telecommunication links, either via optical fibres or the propagation of light in a vacuum (or the atmosphere) for satellite links where our modulators are used.
The information is encoded in both the amplitude and the phase of laser pulses using iXblue solutions: two amplitude modulations AM1 and AM2 are cascaded with a phase modulation PM1.
AM1 generates short optical pulses thanks to an AWG. Very short optical pulses from 70ps can be achieved at 850nm, 1310nm and 1550nm respectively using the NIR-MX800, MXER1300 and MXER high contrast modulator with the DR-VE-10-MO driver. The bias controller MBC-DG-LAB stabilises these pulses for frequency repetition rates up to several GHz.
AM2 generates the random amplitude required for each pulse in CVQKD. This is achieved using the MXAN-LN (C-Band) or the MXAN1300 (O-Band) or NIR-MX800 (for 850nm) with the highly linear DR-VE-10-MO.
The phase modulator PM1 sets the phase of each pulse. The MPZ-LN-10 (selected for both wavelengths 1310nm and 1550nm) with the driver DR-AN-10-HO continuously modulates the phase over the range 0 to 2π. For 850nm, the NIR-MPX800-LN is used. We are proud to provide dedicated modulators, RF drivers and bias controllers to QKD manufacturers and research institutions.
