Topic
Optical polarization
About: Optical polarization is a research topic. Over the lifetime, 13992 publications have been published within this topic receiving 244284 citations.
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TL;DR: In this paper, the impact of quadrature imbalance in an optical coherent QPSK (QPSK) receiver was investigated and the authors showed that the bit-error-rate curves versus optical signal-to-noise ratio (OSNR) penalty can be reduced from 6 to 1 dB with the help of correction algorithms.
Abstract: In this letter, we present the impact of quadrature imbalance in an optical coherent quadrature phase-shift-keying (QPSK) receiver. Arbitrary conjugate misalignment was realized in all-fiber optical hybrid and two correction algorithms of quadrature imbalance, the ellipse correction method, and the Gram-Schmidt orthogonalization method, were independently applied. Bit-error-rate curves versus optical signal-to-noise ratio (OSNR) were measured for the 20-Gb/s optical QPSK signal. We show that OSNR penalty is reduced from ~6 to 1 dB at ~20deg conjugate misalignment with the help of correction algorithms.
59 citations
TL;DR: A fully transparent fiber-optic ring architecture for wavelength division multiplexed (WDM) networks is proposed and the physical topology is based on a single or multifiber ring.
Abstract: A fully transparent fiber-optic ring architecture for wavelength division multiplexed (WDM) networks is proposed. The physical topology of the proposed network is based on a single or multifiber ring. The nodes at the periphery of the network are connected onto the ring via a polarization-independent acoustically tunable optical filter (PIATOF). This device is used for injecting the transmission from each node at a predefined wavelength onto the ring and at the same time for accessing the transmission of the other nodes. Expressions are derived for the throughput of different network configurations. >
59 citations
01 Apr 1964
TL;DR: In this article, a procedure for the synthesis of birefringent networks having arbitrarily prescribed transfer functions is presented, which allows the approximation of a desired function by (n + 1) terms of b fourier exponential series.
Abstract: : A procedure for the synthesis of birefringent networks having arbitrarily prescribed transfer functions is presented. The basic network configuration consists of n identical dascaded birefringent crystals betweenan input and an output polarizer. The crystals are cut with their optic axes perpendicular to their length. The variable determined by the synthesis procedure are the angles of the optic axes of the crystals and the angle of the output polarizer. Any transfer function which is periodic with frequency and whose corresponding impulse response is real and causal can in theory be realized. A network of n crystals allows the approximation of a desired function by (n + 1) terms of b fourier exponential series. (Author)
59 citations
TL;DR: An optical encryption system that uses the polarization of light to encrypt a binary image and a random phase code (key to encrypted data) is experimentally demonstrated.
59 citations
TL;DR: In this paper, it was shown that broad emission lines are observed in the polarized flux spectra of most objects, and the polarization of the lines is at about the same level and position angle as the continuum.
Abstract: Highly polarized QSOs discovered in the Two-Micron All Sky Survey (2MASS) have been observed to determine the source(s) of optical polarization in this near-infrared color-selected sample. Broad emission lines are observed in the polarized flux spectra of most objects, and the polarization of the lines is at about the same level and position angle as the continuum. Generally, the continuum is bluer and the broad-line Balmer decrement is smaller in polarized light than for the spectrum of total flux. Narrow emission lines are much less polarized than the broad lines and continuum for all polarized objects. These properties favor scattering by material close to a partially obscured and reddened active nucleus, but exterior to the regions producing the broad-line emission, as the source of polarized flux in 2MASS QSOs. The largely unpolarized narrow-line features require that the electrons or dust polarizing the light be located at distances from the nucleus not much greater than the extent of the narrow emission line region. The conclusion that the scattering material is located close to the nucleus is reinforced by the observation in four objects of changes in both the degree and position angle of polarization across the broad Hα emission-line profile, indicating that the broad emission line region (BLR) is at least partially resolved from distance of the scatterers. In addition to known high-polarization objects, four 2MASS QSOs with active galactic nucleus (AGN) spectral types of 1.9 and 2 were observed to search for hidden BLRs. Broad lines were detected in polarized light for two of these objects, and the polarizing mechanism appears to be the same for these objects as for the highly polarized QSOs in the sample that readily show broad emission lines in their spectra. The small observed sample of eight type 1 2MASS QSOs has weak [O III] emission in comparison to optically selected AGNs with similar near-infrared luminosity. The observations also show that starlight from the host galaxy contributes a significant amount of optical flux, especially for the narrow-line objects, and support the suggestion that many 2MASS QSOs are measured to have low polarization simply because of dilution of the polarized AGN light by the host galaxy.
59 citations