High-power Erbium-doped Fiber Amplifier Research Articles

A novel large-scale star coupler with only two EDFAs

We propose a novel design for constructing a large-scale transmission star coupler by making use of several conventional passive star couplers and only two high-power erbium-doped fiber amplifiers (EDFAs). Not only the proposed architecture can be adapted to both bidirectional and unidirectional wavelength-division multiplexing (WDM) star networks, but also its size can be increased by a factor of m. This alternative greatly decreases the complexity and cost of making large-bandwidth couplers and relaxes the requirement of designing couplers with a large bandwidth to accommodate the multiple wavelengths.

Loop Erbium-Doped Fiber Amplifiers

A comprehensive study of implementing erbium-doped fiber amplifiers (EDFAs) using a loop configuration is presented. Two different schemes based on the mechanism of directing the loop output are investigated. The amplified spontaneous emission at the output port is 3 dB lower than conventional designs. This configuration is recommended for high-power EDFAs.

Greater than 20%-efficient frequency doubling of 1532-nm nanosecond pulses in quasi-phase-matched germanosilicate optical fibers

We fabricated second-order nonlinear gratings in D-shaped germanosilicate fibers, using thermal poling and periodic electrodes defined by standard photolithography. These gratings, which are up to 75 mm long, were used for efficient quasi-phase-matched frequency doubling of 1.532-mum nanosecond pulses from a high-power erbium-doped fiber amplifier. Average second-harmonic powers as high as 6.8 mW and peak powers greater than 1.2 kW at 766 nm were generated, with average and peak conversion efficiencies as high as 21% and 30%, respectively.

CNR limitations of Er-doped optical fiber amplifiers in AM-VSB video lightwave trunking systems

The CNR limitations of two different types of 980-nm pumped in-line Er-doped optical fiber amplifiers with the same small-signal noise figure to transport multichannel AM-VSB video signals is studied. Experimental results and frequency-domain simulations suggest that the noise figure of a high-power in-line erbium-doped fiber amplifiers (EDFA) should be 5 dB or less when operating deep in saturation (optical input power +3 dBm). Using two such in-line amplifiers produced an AM CNR greater than 50 dB with negligible CSO and CTB distortion degradation for a lightwave trunking link transporting 71 AM-VSB video channels with a total optical link budget of 39 dB. These results can clarify the EDFA selection criteria for AM video lightwave links.

Spectral-linewidth broadening in synchronous Raman fiber amplification caused by cross-phase modulation effects and its suppression

When coherent light is amplified by a synchronous Raman fiber amplifier pumped by output pulses from a high-power erbium-doped fiber amplifier operating in an unsaturated gain regime, the detection efficiency with the heterodyne method is degraded. This degradation is caused mainly by cross-phase modulation effects. It is confirmed that using power-flattened pump pulses can suppress these effects.

Broadband light generation by femtosecond pulse amplification with stimulated Raman scattering in a high-power erbium-doped fiber amplifier

It is shown for the first time to our knowledge that short-pulse amplification in high-power erbium-doped fiber amplifiers, simultaneously accompanied by stimulated Raman scattering, generates a broadband optical spectrum at high output power (270 mW). At 20 dB down from the peak the continuum extended over 329 nm, from 1427 to 1756 nm. The FWHM bandwidth was 125 nm, centered at 1650 nm. The coherence was measured to be 15 fringes, which corresponds to a 25-microm coherence length.

Star couplers with gain using fiber amplifiers

The authors propose a novel technique for constructing large passive star couplers with gain using high-power erbium-doped fiber (EDF) amplifiers. In contrast to other proposed techniques where each output port of the coupler requires its own EDF amplifier, the proposed alternative requires few EDF amplifiers with sufficient output saturation power levels. When used in an FDM/WDM star network, the size of the coupler can be increased by a factor of m using m narrowband EDF amplifiers. Moreover, this alternative avoids coupling the pump-laser light through the star coupler itself, alleviating the requirement on designing large bandwidth couplers to accommodate the signal and the pump wavelengths.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>