In-line and cascaded DWDM transmission using a 15dB net-gain polarization-insensitive fiber optical parametric amplifier.

M F C Stephens,P Harper,M Tan,V Gordienko,N J Doran

doi:10.1364/oe.25.024312

Abstract

We demonstrate and characterize polarization-division multiplexed (PDM) DWDM data transmission for the first time in a range of systems incorporating a net-gain polarization-insensitive fiber optical parametric amplifier (PI-FOPA) for loss compensation. The PI-FOPA comprises a modified diversity-loop architecture to achieve 15dB net-gain, and up to 2.3THz (~18nm) bandwidth. Three representative systems are characterized using a 100Gb/s PDM-QPSK signal in conjunction with emulated DWDM neighbouring channels: (a) a 4x75km in-line fiber transmission system incorporating multiple EDFAs and a single PI-FOPA (b) N cascaded PI-FOPA amplification stages in an unlevelled Nx25km recirculating loop arrangement, with no EDFAs used within the loop signal path, and (c) M cascaded PI-FOPA amplification stages as part of an Mx75.6km gain-flattened recirculating loop system with the FOPA compensating for the transmission fiber loss, and EDFA compensation for loop switching and levelling loss. For the 4x75km in-line system (a), we transmit 45x50GHz-spaced signals ('equivalent' data-rate of 4.5Tb/s) with average OSNR penalty of 1.3dB over the band at 10-3 BER. For the unlevelled 'FOPA-only' 25.2km cascaded system (b), we report a maximum of eight recirculations for all 10x100GHz-spaced signals, and five recirculations for 20x50GHz-spaced signals. For the 75.6km levelled system

Highlights

Since its development in the early 1980s, the erbium doped fiber amplifier (EDFA) has reigned supreme as the de facto amplifier for real-world optical communication systems
For the first time we have demonstrated DWDM transmission in optical systems incorporating a polarization-insensitive fiber optical parametric amplifier (PI-Fiber Optical Parametric Amplifier (FOPA)) to compensate for fiber span loss
The PI-FOPA employed a diversity-loop half-pass loop (HPL) architecture to obtain a practical level of net-gain (16dB) and gain bandwidth of 2.3THz (~18nm)

Summary

Introduction

Since its development in the early 1980s, the erbium doped fiber amplifier (EDFA) has reigned supreme as the de facto amplifier for real-world optical communication systems In order for it to be superseded, we believe a competing technology must show not-only close equivalence for key amplifier features such as noise figure, gain bandwidth, physical size, cost etc., and crucially offer a paradigm-shift improvement in one or more of them. Multiple FOPA amplifications were performed for a single 40Gb/s DPSK signal transmitted within a recirculating loop containing 80km of SSMF [19] This is the only previous demonstration of cascaded in-line FOPA amplification, but it was a non-PI architecture, and the pump and signal required manual polarization alignment and this would not be scalable to DWDM operation. We believe this to be a significant step towards a practically realized FOPA for optical communications

Experimental setup

In-line transmission system results

Conclusions