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Journal of the Korean Physical Society

Novel scheme of polarization-modulated ordinary homodyne detection for measuring the polarization state of a weak field

Sun Hyun Youn

Published Jan 1, 2005• 2 citations
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Related papers

Polarization-Modulated Quadrant Homodyne Detector for Single-Shot Measurement of the Polarization State of a Weak Signal Field

Sun-Hyun Youn, Nitin Jain

Journal of the Korean Physical Society•Jan 15, 2009•0 citations

Measuring the polarization state of the weak signal by the homodyne detection

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Conference on Lasers and Electro-Optics•Jan 1, 2005•0 citations

Measurement of the Polarization State of a Weak Signal Field by Homodyne Detection

Sun-Hyun Youn

Information carried by an optical beam of light can usually be conveyed in the form of a temporal modulation of the intensity, phase, frequency or the polarization of the constituent mode(s). In that regard, homodyne detection is one of the most popular and standard method to measure the quantum mechanical properties of light Yuen & Shapiro (1978); Yuen et al. (1979); Yuen & Shapiro (1980); Yurke (1985). The quantum theory of homodyne detection originated principally from the works of Yuen and Shapiro et al. Yuen & Shapiro (1978); Yuen et al. (1979). In this method, a weak signal field is combined with a strong local oscillator field at a beam splitter, and the resulting signal is measured as a photocurrent. With the homodyne detection method, the quantum state of the signal field, such as the quadrature amplitude of the squeezed state, is easily measured Slusher et al. (1985); Wu et al. (1986 ); Polzik et al. (1992), and the quasiprobability distribution function can be measured by using the so-called optical homodyne tomography Smithey et al. (1993); Banaszek & W’odkiewicz (1996); Wallentowitz & Vogel (1996); Youn et al. (2001). Furthermore, optical homodyne detection is used to eavesdrop on the quantum key in quantum cryptography Hirano et al. (2000).

InTech eBooks•Mar 23, 2012•2 citations

Employing Weak-Field Homodyne Detection for Optical Communications

Michele N. Notarnicola, Stefano Olivares

We investigate the role of weak-field homodyne (WH) measurement for optical communications over a lossy bosonic channel with coherent state encoding. This kind of receiver employs photon-number resolving (PNR) detectors with finite resolution and low-intensity local oscillator. As a figure of merit, we consider the mutual information for both single and double WH detection. At first, we consider a Gaussian input modulation, showing this scheme to be suboptimal with respect to the homodyne and double homodyne capacity, respectively. Thereafter, we investigate the performance of non-Gaussian modulation, by considering a Gamma distribution of the energy of the encoded pulses, and achieve an increase in the information rate with respect to the Gaussian case in all energy regimes. In particular, WH measurement outperforms the Shannon limit for homodyne/double homodyne detection in the photon-starved limit, albeit it does not beat neither the direct detection (DD) limit achieved with Gamma modulation, nor on-off keying (OOK) strategies, e.g. OOK-DD and OOK-Dolinar receiver.

arXiv:2405.14310•IEEE Journal on Selected Areas in Communications•Feb 19, 2025•5 citations

Simultaneous quadrature detection of suppressed-carrier weak-coherent-states using a homodyne optical Costas loop receiver

Josué Aarón López-Leyva, E. García, Francisco Javier Mendieta +2 more

Weak coherent states (WCS) are being extensively employed in quantum communications and cryptography at telecommunications wavelengths. For these low-photon-number applications, simultaneous field quadrature measurements are frequently required, such as in the detection of multilevel modulations in the communications scenario or in cryptographic applications employing continuous variables. For this task multiport balanced homodyne detection (BHD) structures are employed, based on the splitting of the received field into its (non-commutating) in-phase (I) and quadrature (Q) components and their separate beating with a local oscillator (LO) in two BHD. This allows the simultaneous measurements of the 2 quadratures at the price of an additional noise due to the vacuum fields that leak via the unused ports. These schemes require the proper optical phase synchronization between the LO and the incoming field, which constitutes a challenge for WCS reception, especially for suppressed carrier modulations that are required for power economy. For this task, a Costas loop is implemented for low photon number WCS, with the design of an optimum feedback scheme considering the phase diffusion of WCS generated by semiconductor lasers. We implemented an optical Costas loop at 1550 nm based on polarization splitting of the laser field to detect I and Q quadratures simultaneously. We present results on the performance in phase error and bit error rate and compare with corresponding quantum limit.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Sep 1, 2011•1 citation

Experiments on Polarication-Controllable Homodyne Detection

Samyong Bae, Sun Hyun Youn

New Physics Sae Mulli•Jan 1, 2005•0 citations
Information carried by an optical beam of light can usually be conveyed in the form of a temporal modulation of the intensity, phase, frequency or the polarization of the constituent mode(s). In that regard, homodyne detection is one of the most popular and standard method to measure the quantum mechanical properties of light Yuen & Shapiro (1978); Yuen et al. (1979); Yuen & Shapiro (1980); Yurke (1985). The quantum theory of homodyne detection originated principally from the works of Yuen and Shapiro et al. Yuen & Shapiro (1978); Yuen et al. (1979). In this method, a weak signal field is combined with a strong local oscillator field at a beam splitter, and the resulting signal is measured as a photocurrent. With the homodyne detection method, the quantum state of the signal field, such as the quadrature amplitude of the squeezed state, is easily measured Slusher et al. (1985); Wu et al. (1986 ); Polzik et al. (1992), and the quasiprobability distribution function can be measured by using the so-called optical homodyne tomography Smithey et al. (1993); Banaszek & W’odkiewicz (1996); Wallentowitz & Vogel (1996); Youn et al. (2001). Furthermore, optical homodyne detection is used to eavesdrop on the quantum key in quantum cryptography Hirano et al. (2000).
We investigate the role of weak-field homodyne (WH) measurement for optical communications over a lossy bosonic channel with coherent state encoding. This kind of receiver employs photon-number resolving (PNR) detectors with finite resolution and low-intensity local oscillator. As a figure of merit, we consider the mutual information for both single and double WH detection. At first, we consider a Gaussian input modulation, showing this scheme to be suboptimal with respect to the homodyne and double homodyne capacity, respectively. Thereafter, we investigate the performance of non-Gaussian modulation, by considering a Gamma distribution of the energy of the encoded pulses, and achieve an increase in the information rate with respect to the Gaussian case in all energy regimes. In particular, WH measurement outperforms the Shannon limit for homodyne/double homodyne detection in the photon-starved limit, albeit it does not beat neither the direct detection (DD) limit achieved with Gamma modulation, nor on-off keying (OOK) strategies, e.g. OOK-DD and OOK-Dolinar receiver.
Weak coherent states (WCS) are being extensively employed in quantum communications and cryptography at telecommunications wavelengths. For these low-photon-number applications, simultaneous field quadrature measurements are frequently required, such as in the detection of multilevel modulations in the communications scenario or in cryptographic applications employing continuous variables. For this task multiport balanced homodyne detection (BHD) structures are employed, based on the splitting of the received field into its (non-commutating) in-phase (I) and quadrature (Q) components and their separate beating with a local oscillator (LO) in two BHD. This allows the simultaneous measurements of the 2 quadratures at the price of an additional noise due to the vacuum fields that leak via the unused ports. These schemes require the proper optical phase synchronization between the LO and the incoming field, which constitutes a challenge for WCS reception, especially for suppressed carrier modulations that are required for power economy. For this task, a Costas loop is implemented for low photon number WCS, with the design of an optimum feedback scheme considering the phase diffusion of WCS generated by semiconductor lasers. We implemented an optical Costas loop at 1550 nm based on polarization splitting of the laser field to detect I and Q quadratures simultaneously. We present results on the performance in phase error and bit error rate and compare with corresponding quantum limit.