scholarly journals Spectral characterization of SPDC-based single-photon sources for quantum key distribution

Author(s):  
Sabine Euler ◽  
Erik Fitzke ◽  
Oleg Nikiforov ◽  
Daniel Hofmann ◽  
Till Dolejsky ◽  
...  

AbstractIn our laboratory, we employ two biphoton sources for quantum key distribution. The first is based on cw parametric down-conversion of photons at 404 nm in PPKTP waveguide chips, while the second is based on the pulsed parametric down-conversion of 775 nm photons in PPLN waveguides. The spectral characterization is important for the determination of certain side-channel attacks. A Hong-Ou-Mandel experiment employing the first photon source revealed a complex structure of the common Hong-Ou-Mandel dip. By measuring the spectra of the single photons at 808 nm, we were able to associate these structures to the superposition of different transverse modes of the pump photons in our waveguide chips. The pulsed source was characterized by means of single-photon spectra measured by a sensitive spectrum analyzer as well as dispersion-based measurements. Finally, we also describe Hong-Ou-Mandel experiments using the photons from the second source.

2013 ◽  
Vol 11 (03) ◽  
pp. 1350034 ◽  
Author(s):  
MIKOŁAJ LASOTA ◽  
RAFAŁ DEMKOWICZ-DOBRZAŃSKI ◽  
KONRAD BANASZEK

We analyze theoretically the performance of four-state quantum key distribution protocols implemented with a realistic heralded single-photon source. The analysis assumes a noisy model for the detector heralding generation of individual photons via spontaneous parametric down-conversion, including dark counts and imperfect photon number resolution. We identify characteristics of the heralding detector that defines the attainable cryptographic key rate and the maximum secure distance. Approximate analytical formulas are applied to multiplexed detection and compared with results of numerical calculations.


Cryptography ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 24
Author(s):  
Noah Cowper ◽  
Harry Shaw ◽  
David Thayer

The ability to send information securely is a vital aspect of today’s society, and with the developments in quantum computing, new ways to communicate have to be researched. We explored a novel application of quantum key distribution (QKD) and synchronized chaos which was utilized to mask a transmitted message. This communication scheme is not hampered by the ability to send single photons and consequently is not vulnerable to number splitting attacks like other QKD schemes that rely on single photon emission. This was shown by an eavesdropper gaining a maximum amount of information on the key during the first setup and listening to the key reconciliation to gain more information. We proved that there is a maximum amount of information an eavesdropper can gain during the communication, and this is insufficient to decode the message.


2019 ◽  
Vol 9 (21) ◽  
pp. 4580
Author(s):  
Jianji Liu ◽  
Jiachen Liu ◽  
Zhixiang Li ◽  
Ping Yu ◽  
Guoquan Zhang

We develop a method to lock a high-finesse near-unstable Fabry–Perot (FP) cavity (F = 7330) to a frequency stable dye laser operating at 605.78 nm using the Pound–Drever–Hall technique. The experimental results show the feasibility of locking this cavity to different transverse modes. This method links the external FP cavity to the dye laser cavity, and a 379 kHz final linewidth of the FP cavity is achieved. Such a near-unstable cavity is potentially useful for cavity-enhanced spontaneous parametric down-conversion to generate narrow-band single photon or photon pairs in different transverse modes.


2018 ◽  
Vol 26 (20) ◽  
pp. 25921 ◽  
Author(s):  
Chun-Hui Zhang ◽  
Dong Wang ◽  
Xing-Yu Zhou ◽  
Shuang Wang ◽  
La-Bao Zhang ◽  
...  

Author(s):  
D. B. Horoshko ◽  
S. Ya. Kilin

We consider an unambiguous state discrimination attack on the B92 protocol of quantum key distribution, realized on the basis of polarization encoding of photons produced by a single-photon source. We calculate the secure key rate and the maximal tolerable loss for various overlaps between two signal states employed in this protocol. We make also a comparison with a physically impossible attack of perfect quantum cloning, and show that the unambiguous state discrimination is much more dangerous for the B92 protocol, than this attack, demonstrating thus, that the security of quantum key distribution is not always based on the no-cloning theorem.


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