Young Geun Han

A detailed experimental study on single-pump Raman/EDFA hybrid amplifiers: static, dynamic, and system performance comparison

This paper presents an experimental study on the performance comparison of three different schemes of single-pump dispersion-compensating fiber (DCF)-based Raman/erbium-doped fiber amplifier (EDFA) hybrid amplifiers together with a DCF-based Raman-only amplifier in terms of static properties, dynamic properties, and system impact: Raman-only amplifier (Type I), Raman/EDFA hybrid amplifiers recycling residual Raman pump in a cascaded EDF located either after (Type II) or prior to (Type III) a DCF, and a Raman-assisted EDFA (Type IV), the concept of which was proposed by Kurosawa et al. With respect to the overall gain and system impact based on bit error rate (BER) measurements in a transmission system, the hybrid amplifier of Type II was found to have the best performance among the four types while the Raman-only amplifier shows the best tolerance to transient response.

Effect of initial coupling strength on transmission characteristics of long-period fiber grating and its sensing application

We investigate the transmission characteristics of long-period fiber gratings depending on their initial coupling strength during the UV post-exposure on a half region of a grating and their application to simultaneous measurement of bending and temperature.

Development of long-distance temperature sensor based on Raman fiber laser using fiber Bragg gratings

We investigate a long distance temperature sensor with multichannel remote sensing functionality at a 50 km distance using Raman fiber laser based on multiple laser cavities based on FBGs and a tunable chirped FBG.

Raman amplifier-based long-distance temperature/strain sensing system incorporating a combined sensing probe of an FBG and an EFG recyling residual Raman pump

A novel, Raman amplifier-based long-distance sensing system using a combined sensing probe of an erbium-doped fiber (EDF) and a fiber Bragg grating is proposed for simultaneous measurement of temperature and strain. By recycling residual Raman pump power for generation of amplified spontaneous emission in the EDF after distributed Raman amplification in the transmission fiber, the overall system configuration was significantly simplified without requiring any additional broadband light source. A remote sensing operation of simultaneous temperature and strain measurement is obtained at a location of 50 km. High quality of sensing signals with a ~ 11 dB signal-to-noise ratio (SNR) is readily achieved even after the 50 km transmission with distributed Raman amplification.