Stefan R. Luthi

Frequency upconversion in Er3+ doped PbO–GeO2 glasses containing metallic nanoparticles

The authors report the infrared-to-visible frequency upconversion (UPC) process in Er3+ doped PbO–GeO2 glasses containing silver nanoparticles (NPs) with an average diameter of 2.2nm. The absorption spectra of the samples present a band centered at 470nm due to the surface plasmons associated with the NPs. The intensity of the band grows with increasing NP concentration. The experiments were performed by exciting the samples with a 980nm diode laser and observing the UPC emissions in the red-green region. The enhanced UPC intensity is attributed to the local field effect in the proximity of the NPs.

Modeling the distributed gain of single--(1050 or 1410 nm) and dual-wavelength--(800 + 1050 nm or 800 + 1410 nm) pumped thulium-doped fiber amplifiers.

The distributed gain of single- and dual-wavelength-pumped thulium-doped fiber amplifiers is modeled. The excellent agreement between the model and coherent optical frequency domain reflectometry measurements enables us to estimate intrinsic loss, branching ratios of fluorescence originating from the 3H4 level, and cross sections of upconversion pumping at 1050 and 1410 nm for the Tm3+ ions in the fiber. With the branching ratios obtained it is possible to describe induced signal absorption when pumping at 800 nm.

TDFA/Raman hybrid amplifiers covering the entire S-band pumped by a single laser

Hybrid amplifier configurations are reported cascading one Raman and one or two Tm/sup 3+/-doped fiber stages, using a single pump at 1426 nm, allowing seamless amplification of the entire S-band (1460-1530 nm). Different configurations were studied, with gain over the entire band width and peak gain up to 24 dB. Noise figure as low as 7 dB was achieved.

Dual-wavelength pumped TDFAs for S-band optical telecommunication - an evaluation

Different dual-wavelength pumping schemes for thulium-doped fiber amplifiers (TDFA) are characterized and evaluated for their feasibility in S-band optical telecommunication networks. The main focus is on system impairments due to transient effects, gain cross-saturation, and bit error rate.

Transient gain dynamics in 1050/1550 nm dual-wavelength pumped TDFAs upon pump modulation

Signal response for modulation of 1050nm and 1550nm pump power is studied in a dual-wavelength pumped TDFA. Response times characteristic for the upper/lower amplification levels and critical dependence on the subsidiary/main pump ratio are observed.

TDFA-FOPA hybrid for S-band amplification and S-to-C, S-to-L band wavelength conversion

A novel type of hybrid amplifier/wavelength converter is presented, coupling a TDFA and a FOPA module in series. Signal amplification over the entire S-Band (1450-1530 nm) and signal-to-idler conversion from 1540-1630 nm is demonstrated.

Optical Amplifier Hybrid Devices for S-Band Telecommunications--A Comparison

Amplifier hybrids coupling different amplifier types are characterized and evaluated for application in S-band telecommunications. Combinations including a fiber-optic parametric gain module are also studied for S-C/L band wavelength conversion.

Generation of Multiple Idlers at Different Polarizations in Dual-Pump Fiber Optical Parametric Amplifiers: Experiments and Applications

Multiple, polarization-diverse, idlers are generated in a dual-pump fiber parametric amplifier. A polarization beam splitter is employed to separate orthogonally-polarized idlers. The configuration can be used in telecommunications to copy and re-direct data signals

Transient gain behavior in 1050/1550-nm dual-wavelength pumped TDFAs

We present an experimental study on transient events in 1050/1550-nm dual-wavelength pumped thulium-doped fiber amplifiers (TDFAs)-a promising candidate for S-band telecommunication applications. For appropriate power ratios of the two pump wavelengths, transient excursions due to signal add-drop are comparable to those in single-wavelength pumped TDFAs. Pump modulation effects, however, more severely impact the signal gain. With our experimental results, it should be possible to develop transient gain suppression control loops for this TDFA type.