Evolution of amplified spontaneous emission and characterization of an optimized two-mode EDFA system obtained from an extended analytical model

Abstract

An optimized two-mode erbium-doped fiber amplifier (2M-EDFA) system is proposed and evaluated in this paper. The Giles model of a single-mode EDFA is extended to multiple modes. Detailed mathematical analysis of the model indicates that a proper combination of an LP 01 pump and LP 11 pump can equalize the gain of the two modes. The results from mathematical calculations are validated with simulations based on the Runge-Kutta method numerically integrating first-order differential rate equations and propagation equations in the optical domain. Results show that an appropriate LP 01 and LP 11 pump power combination equalizes the gain of the two signal modes to a high value of 27.256 dB. The evolution of the forward-amplified spontaneous emission (ASE) in the designed 2M-EDFA system is investigated. The ASE ratio between the two modes is observed to remain within a factor of 2. The tolerance of the differential modal gain (DMG) with respect to the intrinsic parameters and external operating conditions for the designed 2M-EDFA system is also investigated. In the range of 1530-1560 nm, a modal gain of about 27 dB and ripple of about 0.21 dB are obtained for both modes. This enables transmission of a total of 60 spatial and spectral channels in this range with appropriate spacing. Finally, the immunity of the 2M-EDFA design to the effects of high concentration are investigated.

Modified differential overlap factor and modal gain equalization criteria-based comparative analysis of 4M-EDFA 980;1480 nm towards identification of a unique erbium doping profile for the 4M-EDFA1480 nm system

“…The resulting values have been calculated using Eqs. ( 9) to (11). DMNF plot diagram and DSNF bar diagram are shown in Fig.…”

“…( 21). The values are calculated for 𝜂 𝑠𝑝(𝑙𝑚) (𝜂 𝑠𝑝(01) ; 𝜂 𝑠𝑝 (11) ; 𝜂 𝑠𝑝 (21) and 𝜂 𝑠𝑝(02) ) which are shown in Fig. 15 over the ten core segments.…”

“…The resulting non-linear transmission impairments, make it impossible to increase spectral efficiency indefinitely by raising the launched power [2]. A conventional SMF data carrying capacity limit is determined to be around 100 Tbit/s, which corresponds to the single-mode erbium doped fiber amplifier (SM-EDFA) spectral bandwidth (i.e., 11 THz including the C and L amplification bands) [3]. For overcoming the capacity bottleneck of single-mode fiber, space division multiplexing (SDM) has become a popular study topic in recent years as a method of increasing optical fiber transmission rates.…”

“…It is reported that gain equalisation in few-mode amplifiers with more than two 𝐿𝑃 𝑙𝑚 modes was becoming increasingly challenging due to unique modal profiles [9]. So far, the two most common ways for equalizing modal gain have been managing pump modal contents [10] [11] and optimising erbium spatial distributions [9][12] [13]. Other gain equalisation solutions have been described as well, such as cladding pumped arrangement [14], designing an EDF with a particular refractive index profile [15].…”

Modeling of Amplified Spontaneous Emission Noise for Quantum Communication Applications

“…It, therefore, can be employed to generate random numbers at speedy rates by using high-speed detection and acquisition systems. However, modeling the amplified spontaneous emission in optical amplifiers, mainly in EDFAs, is still under research [11].…”