Large Effective Area Fiber Research Articles

Four-directional Transport of AM-VSB CATV System over 80-km Large Effective Area Fiber

This study proposes and demonstrates, for the first time, a four-directional externally modulated NTSC AM-VSB 77-channel transport system over an 80-km large effective area fiber (LEAF) which uses four-directional transport and dense-wavelength-division-multiplexing (DWDM) techniques. Not only four times of the channel capacity, but also good performances of carrier-to-noise ratio (CNR) ≥ 50 dB, composite second order (CSO) ≥ 65 dB and composite triple beat (CTB) > 63 dB were obtained over an 80-km LEAF transport.

A bidirectional hybrid DWDM system for CATV and OC-48 trunking

We propose and demonstrate, for the first time, a bidirectional hybrid dense wavelength-division-multiplexing (DWDM) system for CATV and OC-48 trunking with two wavelengths for AM-VSB video and two wavelengths for OC-48 baseband digital signal transport. Not only twice of the channel capacity, but also good performances of carrier-to-noise ratio /spl ges/50 db, composite second order (CSO)/spl ges/65 db, composite triple beat /spl ges/63 dB and low bit-error rate (<10/sup -9/) were obtained over an 80-km large effective area fiber transport.

Hybrid dense-wavelength-division-multiplexing system for CATV and 256-QAM transport

We demonstrate a hybrid dense-wavelength- division-multiplexing (DWDM) system for CATV and 256- QAM transport, using a four-wavelength system as an ex- ample. Excellent performances of carrier-to-noise ratio (CNR) .50 dB, composite second order (CSO) .70 dB, and composite triple beat (CTB) .65 dB are obtained for the full channel band. Low bit error rate (BER) ,10 29 is achieved for the eight 256-QAM digital channels after a 100-km large effective area fiber (LEAF) transport. © 2001 Society of Photo- Optical Instrumentation Engineers. (DOI: 10.1117/1.1385339)

Optical fibers with low nonlinearity and low polarization-mode dispersion for terabit communications

Refractive-index nonlinearities have negligible effect on the performance of short-haul fiber-optic communication links utilizing electronic repeaters. However, in long links, nonlinearities can cause severe signal degradations. To mitigate nonlinear effects, a new generation of fibers, referred to as large effective-area fibers, have been introduced in recent years. This paper reviews the latest research and development work on these fibers conducted by several research groups around the world. Attention is focused on a class of large effective-area fibers that are based on a depressed-core multiple-cladding design. Another important issue in long-haul and high capacity fiber optic systems is the polarization-mode dispersion (PMD) which has been recognized as a serious limiting factor. In this paper, an improved fiber design is proposed which, in addition to providing large effective-area and low bending loss, eliminates PMD due to elliptical deformation in the single-mode wavelength region. Furthermore, this design is allowed to provide a small chromatic dispersion about few ps/ nm km , in order to overcome four-wave mixing effects.

Dispersion compensation in externally modulated transport system using chirped fiber grating as well as large effective area fiber

We propose and demonstrate, for the first time, an externally modulated NTSC AM-VSB erbium-doped fiber amplifier repeated system in the 1550-nm region, which uses a chirped fiber grating as well as a large effective area fiber as the dispersion compensation devices. In comparison with the conventional externally modulated fiber optical CATV system, excellent performances of carrier-to-noise ratio ?50 dB, composite second order ?78 dB, and composite triple beat ?68 dB were obtained for the full channel band after a 100-km fiber span transmission.

Long-distance Transport of Directly Modulated Fiber Optical CATV System over 100 km Large Effective Area Fiber

This study presents a directly modulated 1550 nm NTSC AM-VSB 77-channel fiber optical CATV long-distance transport system using push-pull preamplifier and large effective area fiber (LEAF). Good performances of carrier-to-noise ratio (CNR) 50 dB, composite second order (CSO) 62 dB and composite triple beat (CTB) 61 dB were obtained over a 100 km LEAF transport. Compared with a conventional externally modulated system, our proposed system does not require expensive externally modulated transmitter, sophisticated stimulated Brillouin scattering (SBS)-suppression and differential detection techniques, as well as CTB-predistortion circuit. This proposed directly modulated transport system is simpler and more cost-effective than the conventional externally modulated transport system.

Experimental demonstration of bidirectional lightwaveCATV 100 km transmissionsystem using SMF and LEAF links

A bidirectional lightwave 100 km transmission system capable of delivering 80 cable television (CATV) analogue video signals using conventional singlemode fibre (SMF) or large effective area fibre (LEAF) has been demonstrated experimentally for the first time. Elimination of both Rayleigh backscattered crosstalk from the opposite-direction signal and amplified spontaneous emission noise is required to improve the system carrier-to-noise ratio. Satisfactory system performance can be achieved regardless of whether an SMF or LEAF 100 km link is used. However, the composite second-order quality of the LEAF link is superior to that of the SMF link. This technology should play an important role in leased fibre links for trunk delivery between any two multiple system operators across another CATV-operator system.

40 WDM 2.5 Gbit/s transmission over 12000 kmusing widely gain-flattened low-noise 980 nm-pumped EDFAs

40 WDM 2.5 Gbit/s transmission is successfully demonstrated over 12000 km for the first time, using widely gain-flattened low-noise 980 nm-pumped EDFAs and a large effective area fibre. The gain shape of the transmission line was almost maintained over 18000 km.

Enhancement of amplifier spacing in long-haul optical links through the use of large-effective-area transmission fiber

The use of large effective area (LEA) dispersion-shifted fibers is investigated for enhancing the amplifier spacing in long-haul optical links. Our analysis leads to the definition of a novel figure of merit for amplified links, which is valid for both soliton and NRZ systems. It is shown that exploiting fibers with effective areas between 70 and 90 /spl mu/m/sup 2/ enables a dramatic increase of the amplifier spacing (i.e., in excess of 100%) by comparison to systems using classical 50-/spl mu/m/sup 2/ fibers, The maximum attenuation that can be tolerated for LEA fibers is also determined as a function of the effective area. >