MRV Communications EM316EDFA-LPR Manual do Utilizador descarregar pdf (Página 19)

Page 19 / 40

Cédric Ware <[email protected]>

2011

Document License

Modern EDFAs

Usage: all applications on C + L bands

Dynamic gain equalization

Power monitoring (not on individual WDM channels: too costly)

2+ stages, mid-point access → DCF, add-drop

ICTON 2006 115 Tu.C1.2

Optical Amplifiers for Modern Networks

David Menashe, Alex Shlifer and Uri Ghera

RED-C Optical Networks, Atidim Tech. Park, Bldg 3. P.O.B 58101, Tel-Aviv 61580, Israel

Tel: (9723) 6476789, Fax: (9723) 6476990, e-mail: [email protected]

ABSTRACT

Recent trends in optical networks, such as Reconfigurable Optical Add Drop Multiplexing (ROADM) and

optical cross connects, require advanced optical amplifiers based on both Erbium Doped Fibre Amplifiers

(EDFAs) and Raman technology. To address the dynamic nature of modern networks, EDFAs should provide

broadband variable gain operation, flexible mid-stage access, fast transient response to dynamic events, and

advanced spectral monitoring and control to adjust to changing spectral conditions in the network. An important

supplement to EDFA technology is the use of Distributed Raman Amplification (DRA) to achieve transmission

over multi-span Ultra Long Haul (ULH) links in all optical networks, as well as very high loss repeaterless links.

Keywords: optical amplifiers, EDFAs, distributed Raman amplifiers, optical channel monitoring, ROADM.

1. INTRODUCTION

The rapid growth of IP traffic, which now dominates most service provider networks, has placed new demands

on the optical layer of the network. The unpredictable nature of the traffic, coupled with the need to provide

multiple broadband services at ever decreasing cost, has led service providers to demand flexible reconfigurable

optical networks which are self-managed and can seamlessly adjust to dynamic traffic conditions. In the short to

intermediate term, this demand has led to the widespread interest in and deployment of Reconfigurable Optical

Add Drop Multiplexing (ROADM), which allows individual wavelength to be dynamically and remotely

dropped or added at sites along an optical link. In the longer term, Optical Cross Connect (OXCs), also known

as high degree nodes, will be required to create all-optical mesh networks where different wavelengths traverse

different and diverse paths within a multi-point mesh network. Additionally, enhanced protection and restoration

capabilities are required at the optical layer to support carrier class Ethernet and other advanced services.

Being key components in any optical network, optical amplifiers need to support these new requirements.

In particular, they are required to support: Broadband operation over a large dynamic range with respect to

input/output power and gain: Flexible mid-stage access for advanced optical modules such as ROADM devices,

Wavelength Blockers (WBs) and Dynamic Gain Equalizers (DGEs); Fast transient response to sudden dynamic

changes in input power; and Detection of and adjustment to changes in spectral composition of the input signal.

In addition, amplifiers should have minimum Noise Figure (NF) in order to enhance system OSNR and enable

transmission over longer distances without electronic regeneration. In this respect, the use of DRA in

conjunction with conventional EDFAs is a key enabler for ULH transmission and other demanding applications.

2. ADVANCED EDFA MODULES

EDFAs have been widely deployed since the early 90’s, with the basic technology and components now being

both mature and well understood [1]. The basic EDFA design consists of a length of Erbium Doped Fibre

(EDF), pumped by a 980nm pump laser diode. The addition of input and output isolators and detectors, together

with an electronic control unit, represents a single stage amplifier module, as shown in Fig. 1a. Such a module is

typically operated in Automatic Gain Control (AGC) or Automatic Output Power Control (APC), where the

input and output detectors supply the required feedback to the control unit, which in turn controls the pump

power.

Figure 1. (a) Basic Single Stage Amplifier Module, (b) Broadband Variable Gain EDFA.

Isolato

EDF

Pump

Combine

Isolato

980nm

Pump

Input

Detecto

Output

Detecto

Control Unit

(a)

Gain

Stage I

VOA

GFF

Gain

Stage II

Control Unit

(b)

D. Menashe, “Optical Ampliﬁers for Modern Networks”, ICTON 2006.

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 40 41

Comentários a estes Manuais

Sem comentários

MRV Communications EM316EDFA-LPR Manual do Utilizador Página 19

Comentários a estes Manuais