WO2015084145A1 - An apparatus and method for automated flipping of six polarization states of an optical pulse - Google Patents

An apparatus and method for automated flipping of six polarization states of an optical pulse Download PDF

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Publication number
WO2015084145A1
WO2015084145A1 PCT/MY2014/000159 MY2014000159W WO2015084145A1 WO 2015084145 A1 WO2015084145 A1 WO 2015084145A1 MY 2014000159 W MY2014000159 W MY 2014000159W WO 2015084145 A1 WO2015084145 A1 WO 2015084145A1
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optical
linear material
half wave
polarization
triggered
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PCT/MY2014/000159
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French (fr)
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Mohd Fared Abdul Khir
Mohamed Ridza Bin WAH
Mohd Norzaliman Bin MOHD ZAIN
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Mimos Berhad
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
    • H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
    • H04L9/0852—Quantum cryptography
    • H04L9/0858—Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/70—Photonic quantum communication

Definitions

  • the present invention relates to an apparatus and method for automated flipping of six polarization states of an optical pulse.
  • the invention relates to an apparatus and method that provides for automated flipping of an optical pulse input using six states out from three bases to obtain 6DP quantum key distribution protocol.
  • the polarization state of light is known to be used in many technologies ranging from optical sensing to information security.
  • the polarized state of light has been used for example in encoding logical bit for key exchange session between two distant parties. While the usage for four linear polarization states are common, having six polarization states gives more advantage in terms of security.
  • An example of the application with respect to 6DP protocol is introduced by J.S. Shaari, M. Lucamarini, M.R.B. Wahiddin in the Physics Letters A Volume 358 (2): 85.
  • the 6DP Protocol is a Quantum Key Distribution (QKD) protocol which belongs to the two way protocol variant.
  • QKD Quantum Key Distribution
  • protocol such as LM05 and the PingPong protocol which utilizes four and two polarization states.
  • the protocol can be realized using six polarization states of single photon pulses which are used to represent the six quantum states as provided in Europhysics Letter 87 (2009) 10008 entitled “Quantum state engineering with ququarts: Application for deterministic QKD protocol", by A.P. Shurupov, S.S. Straupe, S.P. Kulik, M. Gharib, M.R.B. Wahiddin and in International Patent Application No. PCT/MY2009/000087 entitled "Method of Preparation and Unitary transformation of Quantum States for Quantum Key Distribution” by Mohamed Ridza Wahiddin and Sergey Kulik.
  • the six polarization states can be easily produced for example by using six different laser sources.
  • the 6DP Protocol being a two way protocol, for example the encoding operation at Alice requires her to do a flipping operation against the polarization states of the optical pulses sent by Bob i.e. she has to orthogonally rotate the polarization states of the incoming optical pulse. While in a four states two way protocol e.g.
  • the present invention provide a flipping apparatus and method to orthogonally rotate six degenerate polarization state (H, V, D, A, R, and L) in an automated manner by utilizing two active non-linear materials that act as a half wave plate (HWP) with different preset orientation (45 degree or 0 degree or vice versa) triggered by half wave voltage.
  • the two active non-linear materials are positioned serially to the optical path of the input optical pulse such that the input optical path is made to pass through the said non-linear materials.
  • the present invention relates to an apparatus and method for automated flipping of six polarization states of an optical pulse.
  • the invention relates to an apparatus and method that provides for automated flipping of an optical pulse input using six (6) states out from three (3) bases to obtain 6DP quantum key distribution protocol.
  • One aspect of the invention provides an apparatus (100) for automated flipping of an optical pulse input (108) using six (6) states out from three (3) bases to obtain 6DP quantum key distribution protocol.
  • the apparatus comprising at least one source (102) to prepare at least two non-orthogonal optical pulses; at least a detection module (104) to deterministically measure said pulse pair; at least one data processing module (106, 116) at each end to process said pulse pair; and at least one optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses.
  • the at least one optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses further comprising at least two active non-linear materials (202, 204) utilized to act as half wave plates (HWP) positioned in series with optical path of input; the first non-linear material (202) is orientated at 45 degree from optical axis of an incoming optical pulse and the second non-linear material (204) is orientated at 0 degree from optical axis of the incoming optical pulse; and the polarization states are triggered by half wave voltage generated by the HWP to automatically flip said polarization state to horizontal (H), vertical (V), diagonal (D), anti- diagonal (A), circular right (R), and circular left (L).
  • a further aspect of the invention provides that the input polarization state is flipped by applying either one of four unitary transformation (X, Y, Z and I) achieved with the at least one optical polarization flipper.
  • Yet another aspect of the invention provides that the unitary transformation is X which is when the half wave voltage triggers only the first non-linear material (202).
  • the unitary transformation is iY which is when the half wave voltage triggers both the non-linear material (202, 204).
  • the unitary transformation is Z which is when the half wave voltage triggers only the second non- linear material (204).
  • Still another aspect of the invention provides that the unitary transformation is I which is when the half wave voltage does not trigger any of the two non-linear materials (202, 204).
  • Yet another aspect of the invention provides that the at least two active non-linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input; the position of the first (202) and the second non-linear material (204) can be swapped.
  • HWP half wave plates
  • Another aspect of the invention provides a method (300) for automated flipping of an optical pulse input using six states out from three bases to obtain 6DP quantum key distribution protocol.
  • the method comprising steps of initiating a Quantum Key Distribution (QKD) session by preparing at least two non-orthogonal optical pulses using a source (302); forwarding said non-orthogonal optical pulses through a forward quantum channel to at least one optical polarization flipper to flip logical bits by applying either one of the four unitary transformation (X, iY, Z and I) to at least two active non- linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input (304); and returning pulse pair through a backward quantum channel to the at least one detection module which enables measurement of pulse pair (306).
  • QKD Quantum Key Distribution
  • the X unitary transformation is performed when only the first non-linear material is triggered and the second non-linear material is left as not triggered (406);
  • the Z unitary operation is performed when only the second non-linear material is triggered and the first non-linear material is left not triggered (430);
  • the iY unitary operation is performed when both the first non-linear material is triggered and the second non-linear material is triggered (418);
  • the I unitary operation is performed when both the first non-linear material and the second non-linear material is left not triggered (432).
  • Yet another aspect of the invention provides that the X unitary transformation, the Z unitary transformation, the iY unitary transformation; and the I unitary transformation is randomly applied to a pair of two optical pulses with non-orthogonal polarization by randomly triggering either the first non-linear material or by triggering only the second non-linear material, or by triggering both the first and second non-linear material, or by leaving both the first and second non-linear material as not triggered.
  • FIG. 1.0 illustrates the example of interaction between Bob and Alice which includes flipping operation as provided for in the present invention.
  • FIG. 2.0 illustrates the general architecture of the apparatus for automated flipping of the 6DP protocol of the present invention.
  • FIG 3.0 is a flowchart illustrating the general methodology of the present invention.
  • FIG. 4.0 is a flowchart illustrating architecture of the four (4) conditions of the unitary transformation and the logical bit encoding of the present invention.
  • Table 1.0 illustrates the encoding of the logical bit and the corresponding triggering of the Pockels cell.
  • the present invention relates to an apparatus and method for automated flipping of six polarization states of an optical pulse.
  • the invention relates to an apparatus and method that provides for automated flipping of an optical pulse input using six (6) states out from three (3) bases to obtain 6DP quantum key distribution protocol.
  • the example of the setup (100) shows the interaction between Bob and Alice which includes flipping operation as provided for in the present invention.
  • the apparatus (100) for automated flipping of an optical pulse input (108) using six states out from three bases to obtain 6DP quantum key distribution protocol comprising one source (102) to prepare at least two non-orthogonal optical pulses; a detection module (104) to deterministically measure said pulse pair; a data processing module (106, 116) at each end to process said pulse pair; and an optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses.
  • Bob initiates the Quantum Key Distribution (QKD) session by preparing two non-orthogonal optical pulses using the source (102) and send it to Alice through the forward quantum channel (108).
  • Alice upon receiving the optical pulse pair encode the logical bits (either 00, 01 , 10, 11) by applying either one of the four unitary transformation (X, Y, Z and I) achieved with the optical polarization flipper (112) and return the pulse pair to Bob through the backward quantum channel (110).
  • Bob uses the detection apparatus (104) to deterministically measure the pulse pair using the same basis he used during the preparation stage.
  • FIG. 2.0 illustrate the apparatus for automated flipping of the 6DP protocol as provided for in the present invention.
  • the optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses further comprising two active non-linear materials (202, 204) which are normally the Pockels cells arranged serially inside the driver housings (206) and (208) utilized to act as half wave plates (HWP) positioned in series with optical path of input.
  • the orientation of the first non-linear material (i.e. the first Pockels cell) (202) and the second non-linear material (i.e. the second Pockels cell) (204) are set to be 45 degree and 0 degree respectively from the optical axis of the incoming optical pulse.
  • the position of the two active non-linear materials i.e.
  • both the Pockel cells (202) and (204) act as a half wave plate with their rotation from the optical axis according to the set orientation as the polarization states are triggered by half wave voltage generated by the HWP to automatically flip said polarization state to horizontal (H), vertical (V), diagonal (D), anti- diagonal (A), circular right (R), and circular left.
  • the half wave plates are flipped by applying either one of four unitary transformation (X, Y, Z and I) achieved with the at least one optical polarization flipper.
  • the unitary transformation, X which is when the half wave voltage triggers only the first non-linear material (202) while the unitary transformation, iY which is when the half wave voltage triggers both the non-linear material (202, 204).
  • the unitary transformation, Z which is when the half wave voltage triggers only the second non- linear material (204) and the unitary transformation, I which is when the half wave voltage does not trigger any of the two non-linear materials (202, 204).
  • the optical pulse enter the optical polarization flipper through the forward channel (210), proceed through both the Pockels cells (202) and (204) and finally leaves the driver housing (208) and enter the backward quantum channel (212).
  • a general method (300) of an embodiment of the invention begins by initiating a Quantum Key Distribution (QKD) session by preparing at least two non-orthogonal optical pulses using a source (302). Thereafter, the said non-orthogonal optical pulses is forwarded through a forward quantum channel to an optical polarization flipper to flip logical bits by applying either one of the four unitary transformation (X, iY, Z and I) to the two active non-linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input (304).
  • QKD Quantum Key Distribution
  • HWP half wave plates
  • the X unitary transformation is performed when only the first non-linear material is triggered and the second non-linear material is left as not triggered (406);
  • the Z unitary operation is performed when only the second non-linear material is triggered and the first non-linear material is left not triggered (430);
  • the iY unitary operation is performed when both the first non-linear material is triggered and the second non-linear material is triggered (418); and the I unitary operation is performed when both the first non-linear material and the second non-linear material is left not triggered (432).
  • the pulse pair is returned through a backward quantum channel to the at least one detection module which enables measurement of pulse pair (306).
  • the X unitary transformation, the Z unitary transformation, the iY unitary transformation; and the I unitary transformation is randomly applied to a pair of two optical pulses with non-orthogonal polarization by randomly triggering either the first non-linear material or by triggering only the second non-linear material, or by triggering both the first and second non-linear material, or by leaving both the first and second non-linear material as not triggered.
  • the pair of two optical pulses with non-orthogonal polarization is not necessary position as next to one another.
  • Jones calculus which is often used in dealings with polarization transformation in a fully polarized optical setup as disclosed by E.Collett in the SPIE Press Book 2005 entitled “Field Guide to Polarization”.
  • Jones vector is first denoted for all six polarization states from the three mutually unbiased basis used in this protocol as:
  • Circular right, ⁇ R) [ ]
  • Circular left, ⁇ L) [ .].
  • the M1 and M2 is the X and the Z operator.
  • the two operations can further be combined by conducting matrix multiplication for M1 and M2 and further obtain M12. which act as the iY operator in [1].
  • M12 which act as the iY operator in [1].
  • Table 1.0 shows the four (4) conditions provided for in the invention where the said six (6) degenerate polarization states is being flipped.
  • the four (4) conditions are: i) Not triggering any of the two non-linear materials is assigned as the (I) identity operator; ii) Triggering both non-linear materials is assigned as the (iY) operator. iii) Triggering only the first non-linear material is assigned as the (X) unitary operator; and iv) Triggering only the second non-linear material is assigned as the (Z) unitary operator.
  • the distinguishing features of the present invention lies in a flipping apparatus and the method to orthogonally rotate six degenerate polarization state (H, V, D, A, R, and L) in an automated manner by utilizing two active non-linear materials act as half wave plate (HWP) with different preset orientation (45 degree or 0 degree or vice versa) triggered by half wave voltage.
  • HWP half wave plate

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Abstract

The present invention provides an automated flipping apparatus and method to orthogonally rotate six degenerate polarization state (H, V, D, A, R, and L) in an automated manner by utilizing two active non-linear materials act as half wave plate (HWP) with different preset orientation (45 degree or 0 degree or vice versa) triggered by half wave voltage. The apparatus (100) for automated flipping of an optical pulse input (108) using six states out from three bases to obtain 6DP quantum key distribution protocol comprising at least one source (102) to prepare at least two non-orthogonal optical pulses; at least a detection module (104) to deterministically measure said pulse pair; at least one data processing module (106, 116) at each end to process said pulse pair; and at least one optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses. The at least one optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses further comprising at least two active non-linear materials (202, 204) utilized to act as half wave plates (HWP) positioned in series with optical path of input; the first non-linear material (202) is orientated at 45 degree from optical axis of an incoming optical pulse and the second non-linear material (204) is orientated at 0 degree from optical axis of the incoming optical pulse; and the polarization states are triggered by half wave voltage generated by the HWP to automatically flip said polarization state to horizontal (H), vertical (V), diagonal (D), anti- diagonal (A), circular right (R), and circular left (L).

Description

AN APPARATUS AND METHOD FOR AUTOMATED FLIPPING OF SIX POLARIZATION STATES OF AN OPTICAL PULSE
FIELD OF INVENTION
The present invention relates to an apparatus and method for automated flipping of six polarization states of an optical pulse. In particular, the invention relates to an apparatus and method that provides for automated flipping of an optical pulse input using six states out from three bases to obtain 6DP quantum key distribution protocol.
BACKGROUND ART
The polarization state of light is known to be used in many technologies ranging from optical sensing to information security. In the field of information security, as in the case of quantum cryptography, the polarized state of light has been used for example in encoding logical bit for key exchange session between two distant parties. While the usage for four linear polarization states are common, having six polarization states gives more advantage in terms of security. An example of the application with respect to 6DP protocol is introduced by J.S. Shaari, M. Lucamarini, M.R.B. Wahiddin in the Physics Letters A Volume 358 (2): 85. The 6DP Protocol is a Quantum Key Distribution (QKD) protocol which belongs to the two way protocol variant. Among them also includes protocol such as LM05 and the PingPong protocol which utilizes four and two polarization states. In general, the protocol can be realized using six polarization states of single photon pulses which are used to represent the six quantum states as provided in Europhysics Letter 87 (2009) 10008 entitled "Quantum state engineering with ququarts: Application for deterministic QKD protocol", by A.P. Shurupov, S.S. Straupe, S.P. Kulik, M. Gharib, M.R.B. Wahiddin and in International Patent Application No. PCT/MY2009/000087 entitled "Method of Preparation and Unitary transformation of Quantum States for Quantum Key Distribution" by Mohamed Ridza Wahiddin and Sergey Kulik. The six polarization states can be easily produced for example by using six different laser sources. Unlike other preparation and measurement scheme e.g. the BB84 protocol, the 6DP Protocol, being a two way protocol, for example the encoding operation at Alice requires her to do a flipping operation against the polarization states of the optical pulses sent by Bob i.e. she has to orthogonally rotate the polarization states of the incoming optical pulse. While in a four states two way protocol e.g. the LM05 protocol, realization of the flipper is straight forward as disclosed in a paper entitled "Characterization of Four States Polarization Flipper for Single Photon Application" in Proceeding of the IEEE International Conference on Photonic (ICP2010), Langkawi by Abdul Khir MF, Mohd Zain M N, Suryadi, Saharudin S, Shaari S. and in Optical Engineering, 51 , 045006 entitled "Implementation of Two Way Free Space Quantum Key Distribution", by Abdul Khir MF, Mohd Zain M N, Suryadi, Saharudin S, Shaari S.. However, being a six states protocol, one need to rely on a pair of non-orthogonal optical pulses and the number of flip bits to aid the information exchange.
An example of an experimental work on the 6DP protocol can be found in Europhysics Letter 87 (2009) 10008 entitled "Quantum state engineering with ququarts: Application for deterministic QKD protocol", by Wahiddin et al. and in International Patent Application No. PCT/MY2009/000087 entitled "Method of Preparation and Unitary transformation of Quantum States for Quantum Key Distribution" by Wahiddin and Kulik. While the 6DP protocol itself was successfully realized, one would immediately realize that the experiment was conducted in a manual fashion. For instance, the flipper at Alice which consists of two non-linear materials (half wave plates) had to be manually adjusted their rotation. Further, one needs to remove the non-linear materials (the half wave plates) from the optical path to apply the identity operation (I). While such implementation is enough for a proof of principle, it is certainly not for practical use. One needs an automated apparatus to benefit from the protocol. It is known that one can utilize an electro optic device such as the Pockels cell which can be turned into a half wave plate at certain preconfigured orientation by simply triggering with half wave voltage, thus enabling a fully automated operation. Such implementation can be seen in "Characterization of Four States Polarization Flipper for Single Photon Application" in Proceeding of the IEEE International Conference on Photonic (ICP2010), Langkawi by Abdul Khir MF et.al. and in Optical Engineering, 51 , 045006 entitled "Implementation of Two Way Free Space Quantum Key Distribution", by Abdul Khir MF et.al.The implementation however realizes the flipping of only four linear polarization states (the vertical, horizontal, diagonal and anti-diagonal) which certainly is not for use with the 6DP protocol. Due to the limitations of the existing mechanism, there is a need to develop an apparatus and method to be used as a flipper for six polarization states based on two way quantum key distribution protocol. The present invention provide a flipping apparatus and method to orthogonally rotate six degenerate polarization state (H, V, D, A, R, and L) in an automated manner by utilizing two active non-linear materials that act as a half wave plate (HWP) with different preset orientation (45 degree or 0 degree or vice versa) triggered by half wave voltage. The two active non-linear materials are positioned serially to the optical path of the input optical pulse such that the input optical path is made to pass through the said non-linear materials.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practice.
SUMMARY OF INVENTION
The present invention relates to an apparatus and method for automated flipping of six polarization states of an optical pulse. In particular, the invention relates to an apparatus and method that provides for automated flipping of an optical pulse input using six (6) states out from three (3) bases to obtain 6DP quantum key distribution protocol.
One aspect of the invention provides an apparatus (100) for automated flipping of an optical pulse input (108) using six (6) states out from three (3) bases to obtain 6DP quantum key distribution protocol. The apparatus comprising at least one source (102) to prepare at least two non-orthogonal optical pulses; at least a detection module (104) to deterministically measure said pulse pair; at least one data processing module (106, 116) at each end to process said pulse pair; and at least one optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses. The at least one optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses further comprising at least two active non-linear materials (202, 204) utilized to act as half wave plates (HWP) positioned in series with optical path of input; the first non-linear material (202) is orientated at 45 degree from optical axis of an incoming optical pulse and the second non-linear material (204) is orientated at 0 degree from optical axis of the incoming optical pulse; and the polarization states are triggered by half wave voltage generated by the HWP to automatically flip said polarization state to horizontal (H), vertical (V), diagonal (D), anti- diagonal (A), circular right (R), and circular left (L). A further aspect of the invention provides that the input polarization state is flipped by applying either one of four unitary transformation (X, Y, Z and I) achieved with the at least one optical polarization flipper.
Yet another aspect of the invention provides that the unitary transformation is X which is when the half wave voltage triggers only the first non-linear material (202).
Still another aspect of the invention provides that the unitary transformation is iY which is when the half wave voltage triggers both the non-linear material (202, 204). A further aspect of the invention provides that the unitary transformation is Z which is when the half wave voltage triggers only the second non- linear material (204).
Still another aspect of the invention provides that the unitary transformation is I which is when the half wave voltage does not trigger any of the two non-linear materials (202, 204).
Yet another aspect of the invention provides that the at least two active non-linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input; the position of the first (202) and the second non-linear material (204) can be swapped.
Another aspect of the invention provides a method (300) for automated flipping of an optical pulse input using six states out from three bases to obtain 6DP quantum key distribution protocol. The method comprising steps of initiating a Quantum Key Distribution (QKD) session by preparing at least two non-orthogonal optical pulses using a source (302); forwarding said non-orthogonal optical pulses through a forward quantum channel to at least one optical polarization flipper to flip logical bits by applying either one of the four unitary transformation (X, iY, Z and I) to at least two active non- linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input (304); and returning pulse pair through a backward quantum channel to the at least one detection module which enables measurement of pulse pair (306). The step for forwarding said non-orthogonal optical pulses through a forward quantum channel to at least one optical polarization flipper to encode logical bits by applying either one of the four unitary transformation (X, iY, Z and I) to at least two active non-linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input; the X unitary transformation is performed when only the first non-linear material is triggered and the second non-linear material is left as not triggered (406); the Z unitary operation is performed when only the second non-linear material is triggered and the first non-linear material is left not triggered (430); the iY unitary operation is performed when both the first non-linear material is triggered and the second non-linear material is triggered (418); and the I unitary operation is performed when both the first non-linear material and the second non-linear material is left not triggered (432). Yet another aspect of the invention provides that the X unitary transformation, the Z unitary transformation, the iY unitary transformation; and the I unitary transformation is randomly applied to a pair of two optical pulses with non-orthogonal polarization by randomly triggering either the first non-linear material or by triggering only the second non-linear material, or by triggering both the first and second non-linear material, or by leaving both the first and second non-linear material as not triggered.
The present invention consists of features and a combination of parts hereinafter fully described and illustrated in the accompanying drawings, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
To further clarify various aspects of some embodiments of the present invention, a more particular description of the invention will be rendered by references to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the accompanying drawings in which: FIG. 1.0 illustrates the example of interaction between Bob and Alice which includes flipping operation as provided for in the present invention.
FIG. 2.0 illustrates the general architecture of the apparatus for automated flipping of the 6DP protocol of the present invention.
FIG 3.0 is a flowchart illustrating the general methodology of the present invention.
FIG. 4.0 is a flowchart illustrating architecture of the four (4) conditions of the unitary transformation and the logical bit encoding of the present invention.
Table 1.0 illustrates the encoding of the logical bit and the corresponding triggering of the Pockels cell.
DET AILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates to an apparatus and method for automated flipping of six polarization states of an optical pulse. In particular, the invention relates to an apparatus and method that provides for automated flipping of an optical pulse input using six (6) states out from three (3) bases to obtain 6DP quantum key distribution protocol.
Hereinafter, this specification will describe the present invention according to the preferred embodiments. It is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned without departing from the scope of the appended claims.
Referring to FIG. 1.0, the example of the setup (100) shows the interaction between Bob and Alice which includes flipping operation as provided for in the present invention. The apparatus (100) for automated flipping of an optical pulse input (108) using six states out from three bases to obtain 6DP quantum key distribution protocol comprising one source (102) to prepare at least two non-orthogonal optical pulses; a detection module (104) to deterministically measure said pulse pair; a data processing module (106, 116) at each end to process said pulse pair; and an optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses. Bob initiates the Quantum Key Distribution (QKD) session by preparing two non-orthogonal optical pulses using the source (102) and send it to Alice through the forward quantum channel (108). Alice upon receiving the optical pulse pair encode the logical bits (either 00, 01 , 10, 11) by applying either one of the four unitary transformation (X, Y, Z and I) achieved with the optical polarization flipper (112) and return the pulse pair to Bob through the backward quantum channel (110). Bob uses the detection apparatus (104) to deterministically measure the pulse pair using the same basis he used during the preparation stage.
FIG. 2.0 illustrate the apparatus for automated flipping of the 6DP protocol as provided for in the present invention. The optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses further comprising two active non-linear materials (202, 204) which are normally the Pockels cells arranged serially inside the driver housings (206) and (208) utilized to act as half wave plates (HWP) positioned in series with optical path of input. The orientation of the first non-linear material (i.e. the first Pockels cell) (202) and the second non-linear material (i.e. the second Pockels cell) (204) are set to be 45 degree and 0 degree respectively from the optical axis of the incoming optical pulse. The position of the two active non-linear materials (i.e. the Pockel cells) utilized to act as half wave plates (HWP) positioned in series with optical path of input; the position of the first (202) and the second non-linear material (204) can be swapped. If triggered with half wave voltage, both the Pockels cell (202) and (204) act as a half wave plate with their rotation from the optical axis according to the set orientation as the polarization states are triggered by half wave voltage generated by the HWP to automatically flip said polarization state to horizontal (H), vertical (V), diagonal (D), anti- diagonal (A), circular right (R), and circular left. The half wave plates are flipped by applying either one of four unitary transformation (X, Y, Z and I) achieved with the at least one optical polarization flipper. The unitary transformation, X which is when the half wave voltage triggers only the first non-linear material (202) while the unitary transformation, iY which is when the half wave voltage triggers both the non-linear material (202, 204). Further, the unitary transformation, Z which is when the half wave voltage triggers only the second non- linear material (204) and the unitary transformation, I which is when the half wave voltage does not trigger any of the two non-linear materials (202, 204). The optical pulse enter the optical polarization flipper through the forward channel (210), proceed through both the Pockels cells (202) and (204) and finally leaves the driver housing (208) and enter the backward quantum channel (212).
Referring to FIG. 3.0 and 4.0 respectively, a general method (300) of an embodiment of the invention is illustrated wherein the method (300) begins by initiating a Quantum Key Distribution (QKD) session by preparing at least two non-orthogonal optical pulses using a source (302). Thereafter, the said non-orthogonal optical pulses is forwarded through a forward quantum channel to an optical polarization flipper to flip logical bits by applying either one of the four unitary transformation (X, iY, Z and I) to the two active non-linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input (304). In forwarding the said non-orthogonal optical pulses through a forward quantum channel to the optical polarization flipper to flip logical bits by applying either one of the four unitary transformation (X, iY, Z and I) to two active non-linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input; the X unitary transformation is performed when only the first non-linear material is triggered and the second non-linear material is left as not triggered (406); the Z unitary operation is performed when only the second non-linear material is triggered and the first non-linear material is left not triggered (430); the iY unitary operation is performed when both the first non-linear material is triggered and the second non-linear material is triggered (418); and the I unitary operation is performed when both the first non-linear material and the second non-linear material is left not triggered (432). Subsequently, the pulse pair is returned through a backward quantum channel to the at least one detection module which enables measurement of pulse pair (306). The X unitary transformation, the Z unitary transformation, the iY unitary transformation; and the I unitary transformation is randomly applied to a pair of two optical pulses with non-orthogonal polarization by randomly triggering either the first non-linear material or by triggering only the second non-linear material, or by triggering both the first and second non-linear material, or by leaving both the first and second non-linear material as not triggered. The pair of two optical pulses with non-orthogonal polarization is not necessary position as next to one another.
The configuration can be explained using Jones calculus which is often used in dealings with polarization transformation in a fully polarized optical setup as disclosed by E.Collett in the SPIE Press Book 2005 entitled "Field Guide to Polarization". Jones vector is first denoted for all six polarization states from the three mutually unbiased basis used in this protocol as:
Vertical, \V) = [J]; Horizontal, \H) = [J];
Diagonal, \D) = [J] Anti-diagonal, \A) = [JJ,
Circular right, \R) = [ ], Circular left, \L) = [ .].
Jones matrix for rotatable half wave plate (M) is given by: M— fcos^ sin 25 1
— lsin 29 — cos 20 J ' Pockels cell not in triggered state is equivalent to identity matrix (I) ri o
~ Lo l Pockels cell at orientation Θ to optical axis, triggered with half wave voltage is represented as half wave plate with the following Jones matrix M(0). cos 20 sin 2Θ Λ
M(0) =
.sin 2Θ —cos 2Θ1
By setting the orientation of the first Pockels cell 321 and the second Pockels cell 322 to Θ = - and Θ = 0 respectively, their Jones matrix in triggered state are each given by
4
J] and «2 = [J «J The M1 and M2 is the X and the Z operator. The two operations can further be combined by conducting matrix multiplication for M1 and M2 and further obtain M12.
Figure imgf000013_0001
which act as the iY operator in [1]. One may also swap the position of M1 and M2 such that the orientation of each Pockles cell is swapped. In this way, the combined Pockels cells becomes M21)
Figure imgf000013_0002
which still yields the same output polarization states as with the M 12.
Table 1.0 shows the four (4) conditions provided for in the invention where the said six (6) degenerate polarization states is being flipped. As indicated in Table 1.0, the four (4) conditions are: i) Not triggering any of the two non-linear materials is assigned as the (I) identity operator; ii) Triggering both non-linear materials is assigned as the (iY) operator. iii) Triggering only the first non-linear material is assigned as the (X) unitary operator; and iv) Triggering only the second non-linear material is assigned as the (Z) unitary operator.
The requirement of utilizing the separate wavelength is avoided as the flipping operation of the six polarization states based on two way quantum key distribution protocol is met. The distinguishing features of the present invention lies in a flipping apparatus and the method to orthogonally rotate six degenerate polarization state (H, V, D, A, R, and L) in an automated manner by utilizing two active non-linear materials act as half wave plate (HWP) with different preset orientation (45 degree or 0 degree or vice versa) triggered by half wave voltage.
Unless the context requires otherwise or specifically stated to the contrary, integers, steps or elements of the invention recited herein as singular integers, steps or elements clearly encompass both singular and plural forms of the recited integers, steps or elements.
Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated step or element or integer or group of steps or elements or integers, but not the exclusion of any other step or element or integer or group of steps, elements or integers. Thus, in the context of this specification, the term "comprising" is used in an inclusive sense and thus should be understood as meaning "including principally, but not necessarily solely".
It will be appreciated that the foregoing description has been given by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons of skill in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.

Claims

An apparatus (100) for automated flipping of an optical pulse input (108) using six states out from three bases to obtain 6DP quantum key distribution protocol comprising:
at least one source (102) to prepare at least two non-orthogonal optical pulses;
at least a detection module (104) to deterministically measure said pulse pair;
at least one data processing module (106, 116) at each end to process said pulse pair; and
at least one optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses
characterized in that
the at least one optical polarization flipper (112) to orthogonally rotate polarization states of received optical pulses further comprising: at least two active non-linear materials (202, 204) utilized to act as half wave plates (HWP) positioned in series with optical path of input;
the first non-linear material (202) is orientated at 45 degree from optical axis of an incoming optical pulse and the second non-linear material (204) is orientated at 0 degree from optical axis of the incoming optical pulse; and the polarization states are triggered by half wave voltage generated by the HWP to automatically flip said
polarization state to horizontal (H), vertical (V),
diagonal (D), anti- diagonal (A), circular right (R), and circular left (L).
2. An apparatus (100) as claimed in Claim 1 , wherein the half wave plates are flipped by applying either one of four unitary transformation (X, Y, Z and I) achieved with the at least one optical polarization flipper.
3. An apparatus (100) as claimed in Claim 2, wherein the unitary transformation is X which is when the half wave voltage triggers only the first non-linear material (202).
4. An apparatus (100) as claimed in Claim 2, wherein the unitary transformation is iY which is when the half wave voltage triggers both the non-linear material (202, 204).
5. An apparatus (100) as claimed in Claim 2, wherein the unitary transformation is Z which is when the half wave voltage triggers only the second non- linear material (204).
6. An apparatus (100) as claimed in Claim 2, wherein the unitary transformation is I which is when the half wave voltage does not trigger any of the two non-linear materials (202, 204).
7. An apparatus (100) as claimed in Claim 1 , wherein the at least two active nonlinear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input; the position of the first (202) and the second non-linear material (204) can be swapped.
8. A method (300) for automated flipping of an optical pulse input using six (6) states out from three bases to obtain 6DP quantum key distribution protocol comprising steps of:
initiating a Quantum Key Distribution (QKD) session by preparing at least two non-orthogonal optical pulses using a source (302);
forwarding said non-orthogonal optical pulses through a forward quantum channel to at least one optical polarization flipper to encode logical bits by applying either one of the four unitary transformation (X, iY, Z and I) to at least two active non-linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input (304) ; and returning pulse pair through a backward quantum channel to the at least one detection module which enables measurement of pulse pair (306) characterized in that forwarding said non-orthogonal optical pulses through a forward quantum channel to at least one optical polarization flipper to encode logical bits by applying either one of the four unitary transformation (X, iY, Z and I) to at least two active non-linear materials utilized to act as half wave plates (HWP) positioned in series with optical path of input;
the X unitary transformation is performed when only the first nonlinear material is triggered and the second non-linear material is left as not triggered (406);
the Z unitary operation is performed when only the second nonlinear material is triggered and the first non-linear material is left not triggered (430);
the iY unitary operation is performed when both the first non-linear material is triggered and the second non-linear material is triggered (418); and
the I unitary operation is performed when both the first non-linear material and the second non-linear material is left not triggered (432).
9. A method according to Claim 8, wherein the X unitary transformation, the Z unitary transformation, the iY unitary transformation; and the I unitary transformation is randomly applied to a pair of two optical pulses with non- orthogonal polarization by randomly triggering either the first non- linear material or by triggering only the second non-linear material, or by triggering both the first and second non-linear material, or by leaving both the first and second non-linear material as not triggered.
10. A method according to Claim 8, wherein the pair of two optical pulses with non- orthogonal polarization are not necessary position as next to one another.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108667528A (en) * 2018-04-10 2018-10-16 中国科学院上海技术物理研究所 A kind of round-the-clock quantum communications method based on circular polarization state coding
CN110620654A (en) * 2018-11-02 2019-12-27 科大国盾量子技术股份有限公司 Random polarization state transmitting device, receiving device and quantum communication system

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009157756A2 (en) * 2008-06-27 2009-12-30 Mimos Berhad Method of preparation and unitary transformation of quantum states for quantum key distribution
WO2012018246A1 (en) * 2010-08-05 2012-02-09 Mimos Berhad A six quantum state producing encoder system and a method of producing thereof
WO2012047087A1 (en) * 2010-10-07 2012-04-12 Mimos Berhad Apparatus for flipping the polarization state of an optical pulse between a transmitter and a receiver in quantum key distribution and method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009157756A2 (en) * 2008-06-27 2009-12-30 Mimos Berhad Method of preparation and unitary transformation of quantum states for quantum key distribution
WO2012018246A1 (en) * 2010-08-05 2012-02-09 Mimos Berhad A six quantum state producing encoder system and a method of producing thereof
WO2012047087A1 (en) * 2010-10-07 2012-04-12 Mimos Berhad Apparatus for flipping the polarization state of an optical pulse between a transmitter and a receiver in quantum key distribution and method thereof

Non-Patent Citations (12)

* Cited by examiner, † Cited by third party
Title
A.P. SHURUPOV; S.S. STRAUPE; S.P. KULIK; M. GHARIB; M.R.B. WAHIDDIN: "Quantum state engineering with ququarts: Application for deterministic'QKD protocol", EUROPHYSICS LETTER, vol. 87, 2009, pages 10008
ABDUL KHIR M F ET AL: "Characterization of four states polarization flipper for single photon application", PHOTONICS (ICP), 2010 INTERNATIONAL CONFERENCE ON, IEEE, PISCATAWAY, NJ, USA, 5 July 2010 (2010-07-05), pages 1 - 3, XP031777436, ISBN: 978-1-4244-7186-7 *
ABDUL KHIR MF: "Characterization of Four States Polarization Flipper for Single Photon Application", PROCEEDING OF THE IEEE INTERNATIONAL CONFERENCE ON PHOTONIC (ICP2010
ABDUL KHIR MF: "Implementation of Two Way Free Space Quantum Key Distribution", OPTICAL ENGINEERING, vol. 51, pages 045006
ABDUL KHIR MF; MOHD ZAIN M N; SURYADI, SAHARUDIN S; SHAARI S.: "Implementation of Two Way Free Space Quantum Key Distribution", OPTICAL ENGINEERING, vol. 51, pages 045006
ABDUL KHIR1 M F ET AL: "Implementation of Two Way Free Space Quantum Key Distribution", 1 January 2011 (2011-01-01), pages 1 - 24, XP007922928, Retrieved from the Internet <URL:arxiv.org/pdf/1108.3411> [retrieved on 20141201] *
E.COLLETT: "SPIE Press Book", 2005, article "Field Guide to Polarization"
J.S. SHAARI; M. LUCAMARINI; M.R.B. WAHIDDIN, THE PHYSICS LETTERS A, vol. 358, no. 2, pages 85
LANGKAWI; ABDUL KHIR MF; MOHD ZAIN M N; SURYADI, SAHARUDIN S; SHAARI S: "Characterization of Four States Polarization Flipper for Single Photon Application", PROCEEDING OF THE IEEE INTERNATIONAL CONFERENCE ON PHOTONIC (ICP2010
SHAARI J S ET AL: "Deterministic six states protocol for quantum communication", PHYSICS LETTERS A, NORTH-HOLLAND PUBLISHING CO., AMSTERDAM, NL, vol. 358, no. 2, 9 October 2006 (2006-10-09), pages 85 - 90, XP024929007, ISSN: 0375-9601, [retrieved on 20061009], DOI: 10.1016/J.PHYSLETA.2006.05.007 *
SHURUPOV A P ET AL: "Quantum state engineering with ququarts: Application for deterministic QKD protocol", EUROPHYSICS LETTERS: A LETTERS JOURNAL EXPLORING THE FRONTIERS OF PHYSICS, INSTITUTE OF PHYSICS PUBLISHING, BRISTOL, FR, vol. 87, no. 1, 1 July 2009 (2009-07-01), pages 10008, XP020159616, ISSN: 0295-5075 *
WAHIDDIN: "Quantum state engineering with ququarts: Application for deterministic QKD protocol", EUROPHYSICS LETTER, vol. 87, 2009, pages 10008

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108667528A (en) * 2018-04-10 2018-10-16 中国科学院上海技术物理研究所 A kind of round-the-clock quantum communications method based on circular polarization state coding
CN108667528B (en) * 2018-04-10 2020-11-24 中国科学院上海技术物理研究所 All-time quantum communication method based on circular polarization state coding
CN110620654A (en) * 2018-11-02 2019-12-27 科大国盾量子技术股份有限公司 Random polarization state transmitting device, receiving device and quantum communication system
CN110620654B (en) * 2018-11-02 2022-09-16 科大国盾量子技术股份有限公司 Random polarization state transmitting device, receiving device and quantum communication system

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