Robust hybrid-entanglement for misalignment-resilient free-space QKD
Polarization-entangled photon-based quantum key distribution (QKD) has seen notable advancements, requiring users to share a common frame of reference that might lead to a significant technical overhead of constant monitoring of their frame of reference. In this work, we characterize and demonstrate...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
AIP Publishing LLC
2025-06-01
|
| Series: | APL Quantum |
| Online Access: | http://dx.doi.org/10.1063/5.0261470 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849710267180515328 |
|---|---|
| author | Omshankar Vivek Venkataraman Joyee Ghosh |
| author_facet | Omshankar Vivek Venkataraman Joyee Ghosh |
| author_sort | Omshankar |
| collection | DOAJ |
| description | Polarization-entangled photon-based quantum key distribution (QKD) has seen notable advancements, requiring users to share a common frame of reference that might lead to a significant technical overhead of constant monitoring of their frame of reference. In this work, we characterize and demonstrate hybrid entangled photon pairs for their utilization in rotational alignment-free QKD applications. By employing vortex half-wave retarders that have an azimuthally varying fast axis with a topological charge of q=12, we generate high brightness rotationally invariant hybrid entangled photons and show their resilience against the misalignment of the frame of reference. We demonstrate high fidelity (>92%) entanglement and depict a low quantum bit error rate (QBER) of ∼5−6% (lower than the threshold value of 11%) at a significantly high angle of misalignment θ>45°), in contrast to the polarization-entangled photon pairs that suffer from the degradation of entanglement quality due to a rotational misalignment between the reference frame of communicating entities. The rotationally invariant hybrid photon pairs with robust entanglement properties offer a significant advantage for secure and reliable quantum communication, making them lucrative candidates for applications such as satellite-to-satellite and ground-to-satellite QKD networks. We also show the reliability and stability of the entangled photon source over a long period (measured over 6 h) by demonstrating the BBM92 protocol with a raw key rate of ∼2.8 kbps and a QBER of ∼5% in a single-pass configuration. The performance metrics of our quantum source, measured with conventional avalanche photodiodes (SPADs, quantum efficiency ∼60%, dark counts ∼40 cps), are among the best values reported so far with these detectors. |
| format | Article |
| id | doaj-art-22ffcf0addf445e1baf73bec297008b7 |
| institution | DOAJ |
| issn | 2835-0103 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | APL Quantum |
| spelling | doaj-art-22ffcf0addf445e1baf73bec297008b72025-08-20T03:14:58ZengAIP Publishing LLCAPL Quantum2835-01032025-06-0122026106026106-910.1063/5.0261470Robust hybrid-entanglement for misalignment-resilient free-space QKDOmshankar0Vivek Venkataraman1Joyee Ghosh2Quantum Photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, IndiaQuantum Photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, IndiaQuantum Photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, IndiaPolarization-entangled photon-based quantum key distribution (QKD) has seen notable advancements, requiring users to share a common frame of reference that might lead to a significant technical overhead of constant monitoring of their frame of reference. In this work, we characterize and demonstrate hybrid entangled photon pairs for their utilization in rotational alignment-free QKD applications. By employing vortex half-wave retarders that have an azimuthally varying fast axis with a topological charge of q=12, we generate high brightness rotationally invariant hybrid entangled photons and show their resilience against the misalignment of the frame of reference. We demonstrate high fidelity (>92%) entanglement and depict a low quantum bit error rate (QBER) of ∼5−6% (lower than the threshold value of 11%) at a significantly high angle of misalignment θ>45°), in contrast to the polarization-entangled photon pairs that suffer from the degradation of entanglement quality due to a rotational misalignment between the reference frame of communicating entities. The rotationally invariant hybrid photon pairs with robust entanglement properties offer a significant advantage for secure and reliable quantum communication, making them lucrative candidates for applications such as satellite-to-satellite and ground-to-satellite QKD networks. We also show the reliability and stability of the entangled photon source over a long period (measured over 6 h) by demonstrating the BBM92 protocol with a raw key rate of ∼2.8 kbps and a QBER of ∼5% in a single-pass configuration. The performance metrics of our quantum source, measured with conventional avalanche photodiodes (SPADs, quantum efficiency ∼60%, dark counts ∼40 cps), are among the best values reported so far with these detectors.http://dx.doi.org/10.1063/5.0261470 |
| spellingShingle | Omshankar Vivek Venkataraman Joyee Ghosh Robust hybrid-entanglement for misalignment-resilient free-space QKD APL Quantum |
| title | Robust hybrid-entanglement for misalignment-resilient free-space QKD |
| title_full | Robust hybrid-entanglement for misalignment-resilient free-space QKD |
| title_fullStr | Robust hybrid-entanglement for misalignment-resilient free-space QKD |
| title_full_unstemmed | Robust hybrid-entanglement for misalignment-resilient free-space QKD |
| title_short | Robust hybrid-entanglement for misalignment-resilient free-space QKD |
| title_sort | robust hybrid entanglement for misalignment resilient free space qkd |
| url | http://dx.doi.org/10.1063/5.0261470 |
| work_keys_str_mv | AT omshankar robusthybridentanglementformisalignmentresilientfreespaceqkd AT vivekvenkataraman robusthybridentanglementformisalignmentresilientfreespaceqkd AT joyeeghosh robusthybridentanglementformisalignmentresilientfreespaceqkd |