Shawn X. Wang

Fast wavelength-parallel polarimeter for broadband optical networks

We describe a novel wavelength-parallel polarimeter operating in the light-wave band that measures the complete state of polarization of 256 wavelengths in parallel within 20 ms (software-limited), with the potential for submillisecond operation. By use of fast switching ferroelectric liquid crystals in conjunction with an InGaAs arrayed detector, selection and wavelength-parallel detection of individual polarization components can be achieved within approximately 150 microseconds. This instrument offers unprecedented sensing capability that is relevant to the compensation of polarization-related impairments in high-speed light-wave communications.

Broadband, high spectral resolution 2-D wavelength-parallel polarimeter for Dense WDM systems.

A broadband wavelength-parallel polarimeter has been designed or polarization measurements of multiple Dense WDM channels in parallel, which is based on a 2-D spectral disperser via a diffraction grating and a virtually-imaged phased-array (VIPA). At a hyperfine 2.8 GHz sub-channel spacing, we have demonstrated spectral polarization measurements of ~1500 sub-channels (~32 nm spectral range), with a potential total measurement time of less than 5 ms.

A Complete Spectral Polarimeter Design for Lightwave Communication Systems

The authors describe a fast spectral polarimeter operating in the lightwave communications band capable of measuring both state-of-polarization and degree-of-polarization of hundreds (up to thousands) of spectral components in parallel within milliseconds. In this paper, the design incorporates fast switching ferroelectric liquid crystals for polarization component selection on the 100-mus scale. Dispersion elements and an arrayed detector are used for wavelength-parallel sensing. Bandwidth of coverage can be scaled from a single wavelength-division multiplexed channel to more than 100 nm, and 256 spectral polarization measurements in under 1 ms are verified. Finally, a calibration algorithm is used to minimize measurement error. This instrument offers unprecedented sensing capability relevant to the monitoring and compensation of polarization-related impairments in high-speed lightwave communications

Robust Multiwavelength All-Fiber Source of Polarization-Entangled Photons With Built-In Analyzer Alignment Signal

We describe an all-fiber source of polarization-entangled photons, which is designed to be simple to manufacture and structurally robust. The source includes an alignment signal that allows for straightforward alignment of the measurement axes of the subsequent polarization analyzers. High-quality entangled light is generated and measured at multiple wavelength channels within the C-band.

Monitoring PMD-induced penalty and other system performance metrics via a high-speed spectral polarimeter

We developed and tested a nonintrusive technique for estimating polarization-mode-dispersion-induced system penalties based on spectral polarization measurements. Other system characteristics such as power fluctuations and carrier-frequency drift could also be monitored simultaneously. Our spectral polarimeter works in milliseconds, and can be scaled to monitor all channels in the C-band

Polarization mode dispersion spectrum measurement via high-speed wavelength-parallel polarimetry.

We report experiments in which wavelength-parallel spectral polarimetry technology is used for measurement of the frequency-dependent polarization mode dispersion (PMD) vector. Experiments have been performed using either a grating spectral disperser, configured to provide 13.6 GHz spectral resolution over a 14 nm optical bandwidth, or a virtually imaged phased array spectral disperser, configured for 1.6 GHz spectral resolution over a 200 GHz band. Our results indicate that the spectral polarimetry data obtained via this approach are of sufficient quality to permit accurate extraction of the PMD spectrum. The wavelength-parallel spectral polarimetry approach allows data acquisition within a few milliseconds.

Non-intrusive estimation of PMD-induced penalty via high speed, high resolution spectral polarimeter

We developed and tested a non-disruptive technique for estimating PMD-induced system penalties based on spectral polarization measurements. This technique is able to track penalty in milliseconds, and can be scaled to monitor the C-band

PMD Tolerance Testing of a Commercial Communication System Using a Spectral Polarimeter

A stress study methodology for polarization-mode dispersion (PMD) tolerance testing of commercial telecommunication systems is reported. By inserting additional PMD and using intralink polarization scrambling, multiple configurations of the fiber parameter space are sampled. By monitoring both the preforward-error-correction bit error rates and the spectrally resolved states of polarization or string lengths, the error rates are correlated with the PMD-induced system degradation, and it is shown that it is not correlated with power or optical signal-to-noise-ratio fluctuations. Configurations with the PMD uniformly distributed across the link and lumped at the transmitter or receiver ends are also compared

High resolution and high speed wavelength-parallel polarization sensor for dense WDM systems

We report on a wavelength-parallel polarization sensor with potential to perform /spl les/ 4 GHz-spaced sub-channel polarization measurement for multiple dense WDM channels in parallel, with measurement time of less than 5 ms.

Nonuniform Optical Undersampling for High-Resolution Microwave Frequency Measurements

An optical analog-to-digital converter that uses pulses of multiple wavelengths to nonuniformly sample a microwave signal is used to determine an input microwave frequency to a high accuracy over a large frequency range. Measurement times of 4 μ s lead to frequency errors of ~300 Hz over a measurement range of 10-18 GHz. We also identify the frequency and magnitude of multiple microwave inputs. The simple configuration is robust and practical.