Quantum Key Distribution

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Modern society relies heavily on private telecommunications. Among the many activities that depend on it are e-banking, e-health, or secure government communications. However, modern encryption techniques used to establish privacy have limitations as they rely most often on the supposition that an eavesdropper has access to a limited computational power. This supposition depends on whether the eavesdropper is an individual or a state agency. Also, his computational power may be much larger in a decade (20-years-old communications are much easier to decrypt nowadays). Now, Quantum Key Distribution (QKD) offers a forever privacy guaranteed by the laws of physics.

CVQKD using iXblue Modulators and matching RF amplifiers

Thanks to QKD, a spy trying to intercept some information is detected before a message is even sent. And this is achieved simply by adapting the emitter and receiver hardware of an optical link (no need to send guards all along your optical fiber). In practice, QKD is achieved with optical telecommunication links, either via optical fibers or the propagation of light in vacuum (or the atmosphere) for satellite links where iXblue modulators are used.

An example of Continuous Variable QKD (CVQKD) is given. The information is encoded in both the amplitude and the phase of laser pulses using iXblue solutions: two amplitude modulation blocks AM1 and AM2 are cascaded with a phase modulation PM1.

Quantum Key Distribution

Using an AWG, a first modulation block AM1 is used to generate short optical pulses. Using iXblue NIR-MX800MXER1300 and MXER high contrast and wide bandwidth amplitude modulators, very short optical pulses width from 70 ps can be achieved at 850 nm, 1310 nm and 1550 nm respectively. The modulator is combined with the driver DR-VE-10-MO which can be set either as a limiting or linear amplifier for either square or gaussian pulse waveforms. Using iXblue bias controller MBC-DG-LAB, a high pulse contrast stability is obtained for frequency repetition rates up to several GHz.


An additional modulation block 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 850 nm) and the highly linear DR-VE-10-MO.

A phase modulator PM1 sets the phase of each pulse. The MPZ-LN-01 (coming with more than 3 GHz electro-optical bandwidth) or the MPZ-LN-10 (typical 16 GHz of bandwidth) is used in combination with the driver DR-AN-10-HO to continuously modulate the phave over the range 0 to 2π. For the O-Band operation, the MPZ-LN-10 is selected to operate at both wavelengths 1310 nm or 1550 nm. For 850 nm, NIR-MPX800-LN-05 (8 GHz bandwidth operation) or the NIR-MPX800-LN-10 (more than 16 GHz bandwidth) are used.

iXblue provides modulation solutions to QKD manufacturers and to research institutions. In addition to the solutions listed above, iXblue also offers polarization switches and pulse pickers. iXblue is also participating to the OpenQKD consortium. By offering dedicated modulators, bias controllers and RF drivers, pulse-pickers for receiver temporal pulse selection, iXblue is proud to contribute efficiently to the deployment QKD.

Components solution for Quantum

From components to fiber system and laser solutions for cold atom and quantum application

On June 2nd 2021, iXblue Photonics presented our solutions for quantum physics at a DAMOP Workshop: from components to fiber system and laser solutions for cold atom and quantum application. In the first part of this live presentation, we introduce iXblue components solutions for Quantum Key Distribution, and more precisely for Continuous Variable QKD.
iXblue proposes state-of-the-art components that improve Alice’s transmitter efficiency. They are Phase and Amplitude Modulators, RF amplifiers and come with outstanding performance such as low insertion loss modulators, high extinction ratio amplitude modulators, highly linear RF amplifier, …


Dedicated products

Wavelength max (nm) : 780 – 1580

Product Specification Datasheet
ANalog Drivers
DR-VE-10-MO 12 GHz VErsatile RF Amplifier PDF More info
DR-AN-10-HO 10 GHz Analog High Output Voltage Driver Module PDF More info
MXER1300-LN-10-PD-P-P-FA-FA-30dB 1310 nm band
10 GHz High Extinction Ratio Intensity Modulator
PDF More info
MX1300-LN-10-PD-P-P-FA-FA 1310 nm band
10 GHz Intensity Modulator
PDF More info
MPZ-LN-10-00-P-P-FA-FA-Oband 1310 nm band
10 GHz Phase Modulator
PDF More info
NIR 800 nm Band
NIR-MX800-LN-10-00-P-P-FA-FA 800 nm band
10 GHz Intensity Modulator
PDF More info
NIR 800 nm Band
NIR-MPX800-LN-05-00-P-P-FA-FA 800 nm band
10 GHz Phase Modulator
PDF More info
NIR-MPX800-LN-10-00-P-P-FA-FA 800 nm band
16 GHz Phase Modulator
PDF More info


  • Experimental Demonstration of High Key Rate and Low Complexity CVQKD System with Local Local Oscillator

    Shengiun Ren, Shuai Yang, Adrian Wonfor, Richard Penty, Ian White (University of Cambridge)

    Optical Fiber Communication Conference – January 2020

    We experimentally demonstrate a 250MHz repetition rate Gaussian-modulated coherent-state CVQKD with local local oscillator implementation which is capable of realizing record 14.2 Mbps key generation in the asymptotic regime over 15km of optical fiber…

    More info
  • Orbital Angular Momentum States Enabling Fiber-based High-dimensional Quantum Communication

    Daniele Cozzolino, Davide Bacco, Beatrice Da Lio, Kasper Ingerslev, Yunhong Ding, Kjeld Dalgaard, Michael Galili, Karsten Rottwitt, Leif Katsuo Oxenlowe (TU of Denmark) ; Poul Kristensen (OFS-Fitel) ; Siddharth Ramachandranh (Boston University)

    Quantum networks are the ultimate target in quantum communication, where many connected users can share information carried by quantum systems. The keystones of such structures are the reliable generation, transmission, and manipulation of quantum states. Two-dimensional quantum states, qubits, are steadily adopted as information units. However, high-dimensional quantum states, qudits, constitute a richer resource for future quantum networks, exceeding the limitations imposed by the ubiquitous qubits…

  • Continuous-variable quantum key distribution based on a plug-and-play dual-phase-modulated coherent-states protocol

    Duan Huang, Peng Huang, Tao Wang, Huasheng Li, Yingming Zhou (Shanghai Jiao Tong University) ; Guihua Zeng (Shanghai Jiao Tong University) (Northwest University Xi’an)

    We propose and experimentally demonstrate a continuous-variable quantum key distribution (CV-QKD) protocol using dual-phase-modulated coherent states. We show that the modulation scheme of our protocol works equivalently to that of the Gaussian-modulated coherent-states (GMCS) protocol, but shows better experimental feasibility in the plug-and-play configuration…

  • Polarization-multiplexing-based measurementdevice-independent quantum key distribution without phase reference calibration

    Hongwei Liu, Jipeng Wang (National Univ. of Defense Technology, Hunan) (Beijing Univ. of Posts and Telecom.) ; Haiqiang Ma ((Beijing Univ. of Posts and Telecom.) ; Shihai Sun (National Univ. of Defense Technology, Hunan)

    Optica Vol. 5, No. 8 / August 2018

    Reference-frame-independent measurement-device-independent quantum key distribution (RFI-MDI-QKD) can reduce the complexity of practical systems caused by the alignment of the reference frame. Lengthening the transmission distance and improving the system clock rate are essential in practical applications of QKD. ..

    Read more