Experimental Two Way Quantum Key Distribution with Decoy State

We report on the first demonstration of a two way Quantum Key Distribution protocol with decoy state. The experiment was conducted over free space medium and exhibits a significant increase in the maximum secure distance

Method and apparatus for quantum-mechanically generating a random number

A method (100) and apparatus (200) for quantum-mechanically generating a random number based on polarization states of spontaneous parametric down- converted photons. The method (100) and apparatus (200) comprises a photon source (202) to generate a beam of photons (102), a first type-l nonlinear crystal (206) and a type-l second nonlinear crystal (207) to down-convert the beam of photons through spontaneous parametric down conversions to generate a pair of unidirectional beam of photons with random polarization states (104), characterized in that the first type-l nonlinear crystal (206) is adjacent to the second type-l nonlinear crystal (207) and optical axis of the first type-l nonlinear crystal (206) is orthogonal to optical axis of the second type-l nonlinear crystal (208), a polarized beam splitter (210) to split the pair of unidirectional beam of photons based on polarization states of the pair of unidirectional beam of photons into a beam of horizontally polarized photons and a beam of vertically polarized photons (106), a first detector (212) and a second detector (214) to detect the presence of the beam of horizontally polarized photons and the beam of vertically polarized photons respectively (108), and an electronic logic (216) to assign a first value to every photon in the beam of horizontally polarized photons and assign a second value to every photon in the beam of vertically polarized photons to generate a random number (110)

Characterization of four states polarization flipper for single photon application

We report characterization result using weak coherent pulses on four states polarization flipper utilizing two Pockels cells. Visibility of nearly 90 and above was achieved for each four linear polarization input states. A good polarization contrast between not flipped and flipped states shows that this configuration can be applied for single photon applications

Experimental two way quantum key distribution with weak+vacuum decoy state

We report a free space based experimental demonstration of a two way Quantum Key Distribution protocol withweak+vacuum decoy state. By utilizing a different key rate formula a better maximum secure distance closer to the theoretical infinite was achieved

Erroneous signal detection and secure distance improvement in two way Quantum Key Distribution protocol with decoy state

The erroneous signal detection characterizes the quality of alignment and stability of a Quantum Key Distribution (QKD) system. Its effect against the improvement to the maximum secure distance achievable with weak+vacuum decoy state and a two way Quantum Key Distribution protocol, namely the LM05 protocol is investigated. The result from our numerical simulation suggested that the secure distance improvement for the two key rate formulas are stable only when erroneous signal detection is at below 5%. Interestingly, at beyond 5 %, the two secure key rate formulas exhibit opposite result with one tends to increase while the other tends to decrease

Experimental two way quantum key distribution with weak+vacuum decoy state

We report a free space based experimental demonstration of a two way Quantum Key Distribution protocol with weak+vacuum decoy state. By utilizing a different key rate formula a better maximum secure distance closer to the theoretical infinite was achieved

Method and apparatus for optical polarization photon generator

A method and apparatus for optically generating polarized photons with at least four polarization states is disclosed. The method and apparatus comprises at least two laser sources that are electronically triggered at random to generate at least two optical pulses (102), an arrangement of passive optical components that polarize each optical pulse of the at least two optical pulses to have orthogonal polarization states (104) and merge the at least two optical pulses having orthogonal polarization states onto a single optical path (106) and an active optical component that alters the orthogonal polarization states of the single optical path to have secondary orthogonal polarization states (108)

Decision Tree Algorithm for the Classification of Dental Caries Severity via Saliva

Dental caries is one of the most prevalent chronic diseases. Early detection is prominent to avoid the tooth weakening or worst the tooth loss. UV absorption spectroscopy is a non-invasive technique used for the detection of salivary alpha-amylase which are increasing in the presence of caries. Spectrum acquired from patient at Faculty of dentistry, UKM showed significant peak around 260-300 nm which are correspond to the absorption of amino acid found in salivary alpha-amylase. The spectra are preprocesses using autoscale and multiplicative scatter correction (MSC) to optimize the signal. Decision tree algorithm was implemented on the UV absorption spectra. The best model of decision tree obtained when using autoscale preprocessing method. The accuracy, precision, sensitivity and specificity for the validation data obtained were 0.65, 1.00, 0.29 and 1.00 respectively. The decision tree requires more tuning for the robustness for future application

Decision Tree Algorithm for the Classification of Dental Caries Severity via Saliva

Dental caries is one of the most prevalent chronic diseases. Early detection is prominent to avoid the tooth weakening or worst the tooth loss. UV absorption spectroscopy is a non-invasive technique used for the detection of salivary alpha-amylase which are increasing in the presence of caries. Spectrum acquired from patient at Faculty of dentistry, UKM showed significant peak around 260-300 nm which are correspond to the absorption of amino acid found in salivary alpha-amylase. The spectra are preprocesses using autoscale and multiplicative scatter correction (MSC) to optimize the signal. Decision tree algorithm was implemented on the UV absorption spectra. The best model of decision tree obtained when using autoscale preprocessing method. The accuracy, precision, sensitivity and specificity for the validation data obtained were 0.65, 1.00, 0.29 and 1.00 respectively. The decision tree requires more tuning for the robustness for future application