An analytic method is described for fully characterizing the gain of an erbium-doped fiber amplifier (EDFA) that is based on easily measured monochromatic absorption data. The analytic expressions presented, which involve the solution of one transcendental equation, can predict signal gains and pump absorptions in an amplifier containing an arbitrary number of pumps and signals from arbitrary directions. The gain of an amplifier was measured over a range of more than 20 dB in both pump and signal powers. The measured theoretical results agreed to within 0.5 dB. Although the results described apply explicitly to EDFAs pumped in the 1480-nm region, they are also applicable to EDFAs pumped in the 980-nm region. The method is valid whenever the gain saturation by amplified spontaneous-emission noise can be neglected, which is typically the case for amplifiers with less than about 20 dB of gain. >

Modeling of gain in erbium-doped fiber amplifiers

This invention is a rare earth doped optical amplifier with increased gain and lowered pump thresholds. The amplifying scheme is based on a 3 level lasing system rather than the more prevalent 4 level lasing system. Additionally, the transmission mode of the optical fiber at the pump wavelength has a radius which is substantially equal to or greater than the radius of the distribution profile of the rare earth ions in the fiber amplifier core. With the inventive amplifier, a gain of 37 dB and a saturation power of 11.3 dBm has been obtained with only 54 mW of launch power at λ=1.49 μm.

Erbium-doped fiber amplifier

Half a century has passed since Theodore Maiman's small ruby rod crossed the threshold of laser emission. The breakthrough demonstration earned headlines, but in the early years the laser was called "a solution looking for a problem," and there was a germ of truth in the joke. Years of development since then have vastly improved laser performance, and tremendously increased their variety, earning lasers important roles in scientific research, consumer products, telecommunications, engineering, medicine, materials working, and a host of other applications. This article reviews the highlights of those developments and puts them into context, showing how laser technology has evolved to meet application requirements.

https://www.spiedigitallibrary.org/journals/optical-engineering/volume-49/issue-9/091002/Short-history-of-laser-development/10.1117/1.3483597.pdf

Short history of laser development

We have generated pulses as short as 4 psec at 1530 nm from a mode-locked erbium-doped fiber laser. The mode locker is a wide-bandwidth, lithium niobate guided-wave modulator, and the fiber laser is completely integrated. We present evidence that soliton pulse shaping is playing a key role in the formation of the pulses.

Mode-locked erbium-doped fiber laser with soliton pulse shaping

A study of the complex atomic susceptibility of erbium-doped fiber amplifiers operating near the 1.53- mu m transition (/sup 4/I/sub 13/2/-/sup 4/I/sub 15/2/) developed from a semiclassical theoretical description is presented. Expressions for the emission cross section sigma /sub e/( lambda ) and absorption cross section sigma /sub a/( lambda ) of erbium:glass as a quasi-three-level laser system with Stark-split sublevel manifolds are derived. The results are used to calculate the cross sections of aluminosilicate erbium-doped fibers at low temperatures (T=4.2, 77 K) and at room temperature. It is demonstrated that an expression for the gain coefficient of the fiber amplifier can be derived from the expression of the susceptibility. Using Kramers-Kronig relations, an expression for the refractive index change in the fiber is derived. The theoretical spectral gain profile of the fiber amplifier and concurrent refractive index changes are analyzed for different pumping regimes. >

Study of the complex atomic susceptibility of erbium-doped fiber amplifiers

By choosing pump wavelengths at which excited state absorption does not occur, efficient high gain operation of erbium-doped fibre amplifiers is possible. Practical pump wavelengths of 532nm and 980nm are identified as optimal, giving gains as high as 1.35 dB/mW and 2.2 dB/mW of pump at the two wavelengths, respectively.

/pdf/efficient-pump-wavelengths-of-erbium-doped-fibre-optical-e7deeevcui.pdf

Efficient pump wavelengths of erbium-doped fibre optical amplifier

By choosing pump wavelengths which avoid excited-state absorption, efficient, high-gain, erbium-doped fibre amplifiers are possible Practical pump wavelengths of 532nm and 980nm are identified as optimal, the latter giving a gain as high as 22dB/mW of pump

Optimal pumping of erbium-doped-fibre optical amplifiers

https://ieeexplore.ieee.org/iel3/68/3520/00124873.pdf

F. Fontana

Papers

Efficient pump wavelengths of erbium-doped fibre optical amplifier

Optimal pumping of erbium-doped-fibre optical amplifiers

Optimum Design of Nd-Doped Fiber Optical Amdifiers