Polarization State Dynamics of Single Photon Pulse Under Stochastic Polarization Mode Dispersion for Optical Fiber Quantum Channels

TL;DR

This paper studies how stochastic polarization mode dispersion affects the polarization and fidelity of single photon pulses in optical fiber quantum communication, revealing their dynamic behavior and dependence on fiber birefringence fluctuations.

Contribution

It introduces a stochastic birefringence model to analyze polarization state dynamics and fidelity decay in single photon pulses over optical fibers.

Findings

Fidelity decreases rapidly and stabilizes along the fiber.

Larger birefringence fluctuations increase fidelity.

Degree of polarization remains nearly constant for small fluctuations.

Abstract

We investigate the polarization state dynamics of single photon pulse for optical fiber quantum communication channels. On the basis of a birefringence vector model in which amplitude and direction are both stochastic variables, Jones vector is obtained by solving the frequency domain wave equation. The fidelity of output quantum state and degree of polarization of the pulse are also obtained from the density operators. It is shown that the fidelity of quantum state decreases quickly and tends to a stable value along optical fiber, and increases for larger mean fluctuation magnitude of the stochastic fiber birefringence. Degree of polarization is nearly constant for small mean fluctuation magnitude of the birefringence. The fidelity and degree of polarization vary in the same way for Gaussian and rectangular frequency spectrum envelope, while the value of Lorentzian spectrum is smaller.