Biomedical subjects

Inuk Kang

Publications and source records attributed to Inuk Kang.

5 recordsLinked to original sources

PubMed2005

Highly sensitive differential tomographic technique for real-time ultrashort pulse characterization.

We demonstrate a highly sensitive real-time optical pulse characterization technique based on differential chronocyclic tomography. The spectral intensity and phase of the pulse under test are reconstructed analytically from two experimental traces measured simultaneously in the spectral domain. The high sensitivity and accuracy are made possible by lock-in detection of the differential spectra in the simplified chronocyclic tomography. An accuracy of approximately 0.04 rad of spectral phase recovery is achieved with a 10-Hz refresh rate and 10-microW sensitivity. We also show that the measurement technique is applicable to pulses as short as approximately 100 fs.

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PubMed2003

Implementation of electro-optic spectral shearing interferometry for ultrashort pulse characterization.

Electro-optic spectral shearing interferometry is implemented for the highly sensitive characterization of ultrashort pulses from a free-running source. A simple phase-locked-loop clock recovery circuit is used to extract the high-frequency microwave clock signal to drive the phase modulator for spectral shearing. We demonstrate accurate full temporal characterization of 200-fs pulses from an optical parametric oscillator at 5-pW average power.

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PubMed2003

Experimental test of dense wavelength-division multiplexing using novel, periodic-group-delay-complemented dispersion compensation and dispersion-managed solitons.

In an all-Raman amplified, recirculating loop containing 100-km spans, we have tested dense wavelength-division multiplexing at 10 Gbits/s per channel, using dispersion-managed solitons and a novel, periodic-group-delay-complemented dispersion-compensation scheme that greatly reduces the timing jitter from interchannel collisions. The achieved working distances are approximately 9000 and approximately 20,000 km for uncorrected bit error rates of <10(-8) and <10(-3), respectively, the latter corresponding to the use of "enhanced" forward error correction; significantly, these distances are very close to those achievable in single-channel transmission in the same system.

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PubMed2003

Complete temporal characterization of short optical pulses by simplified chronocyclic tomography.

A new self-referencing technique to characterize the temporal electric field of a short optical pulse is presented. The group delay of the pulse is directly obtained from two projections of the Wigner-Ville function after rotation of the pulse in chronocyclic space. Implementation of the technique requires only quadratic temporal phase modulation and two spectrum measurements, from which the electric field is directly and unambiguously reconstructed without any assumption. A device based on these principles is used to characterize the electric field of a 2-ps optical pulse.

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PubMed2003

Highly sensitive direct characterization of femtosecond pulses by electro-optic spectral shearing interferometry.

We report what is to our knowledge the first experimental demonstration of spectral shearing interferometry by use of an electro-optic temporal phase modulator to generate the spectral shear. This approach achieves far better sensitivity than nonlinear optical pulse characterization techniques, including other versions of spectral shearing interferometry. Temporal phase modulation is conceptually simple and is implemented easily with telecommunication components. The technique is versatile, and a wide range of pulse durations can be measured with minimal changes in the setup. We demonstrate the accurate characterization of a 156-MHz train of 1540-nm pulses with durations ranging from 750 fs to more than 30 ps after various amounts of chirping, at average powers below 1 microW.

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