B. Bakhshi

RZ-DPSK field trial over 13,100 km of installed non slope-matched submarine fibers

This work presents the first field trial using the return-to-zero differential-phase-shift-keying (RZ-DPSK) modulation format. A 96/spl times/10-Gb/s RZ-DPSK field trial was conducted over a 13 100-km optical undersea path by double passing the installed 6550-km underwater link which was deployed with non-slope-matched submarine fibers. All channels performed with more than a 3-dB forward-error correction margin, including channels that accumulated over /spl plusmn/13 000ps/nm of dispersion. It is also shown that the RZ-DPSK format has similar residual dispersion and channel power tolerance for both slope-matched and non-slope-matched fibers. Furthermore, it is demonstrated that the chirped RZ-DPSK format could further improve system performance by 1-2 dB.

Experimental comparison of the RZ-DPSK and NRZ-DPSK modulation formats

The RZ-DPSK and NRZ-DPSK modulation formats were experimentally compared using installed undersea fiber links. Our results show a 1-1.5 dB RZ benefit with optimized RZ modulation depth for both 25-GHz and 33-GHz spaced channels.

Reducing interchannel crosstalk in long-haul DWDM systems

Nonlinear interaction between signal channels may result in significant performance degradation in transoceanic dense wavelength-division-multiplexing (WDM) transmission systems operated at high bit rates. In this paper, we report that the nonlinear crosstalk for systems with high spectral efficiency can be suppressed if WDM channels are launched with orthogonal relative states of polarization. It is shown that for adjacent channels (that experience the strongest nonlinear interaction) the launched relative state of polarization is maintained over the large distance of low polarization-mode dispersion fiber typically used in undersea systems. Numerical studies, as well as experimental results, are presented for standard and dispersion slope-matched dispersion maps.

Terabit/s field trial over the first installed dispersion-flattened transpacific system

We present results of a successful field trial at 96 /spl times/ 12.3 Gb/s per fiber over the first installed dispersion-flattened transpacific system, 8991-km long, part of the Tyco Global Network/sup /spl trade//, plus experimental results for 128 /spl times/ 12.3 Gb/s over the same path.

Optical test equipment for performance evaluation of installed DWDM systems

We have developed a TOTE/spl trade/ technique for evaluation of the full capacity performance of DWDM systems without need for full terminal equipment. The presented TOTE/spl trade/ design works independently of the system bandwidth and channel spacing and is thus very attractive for performance evaluation of installed DWDM systems. In a 28 nm, transatlantic DWDM field transmission experiment, the presented TOTE/spl trade/ design is verified to accurately measure the same gain shape and performance as the fully loaded transmitter.

Polarization tracking receiver demonstration over transoceanic distance

We demonstrated the feasibility of a polarization tracking receiver in a 6500 km straight line transmission experiment. This is the first transoceanic length DWDM demonstration using a fully automatic polarization tracker producing a record setting 66 % spectral efficiency for 10 Gb/s transmission.

Spectral hole burning simulation and experimental verification in long-haul WDM systems

The effect of spectral hole burning on long-haul WDM systems was simulated and measured on installed transatlantic link. Changes in end-to-end system gain versus number and wavelength of channels were evaluated. Modeling results are in good agreement with experimental data.

Impact of gain-flattening-filter ripple in long-haul WDM systems

We present a detailed study of the impact of fiber-Bragg-grating gain-flattening-filter ripple in a 28 nm, 64/spl times/12.3 Gb/s WDM loop transmission experiment up to 6050 km. For 1 RAD CRZ modulation format and a ripple period equivalent to half the bit-rate, we show that the ripple-induced Q-factor penalty is about 0.2 dB per dB intrachannel integrated gain ripple.

Impact of spectral hole burning on initial loading scenarios in DWDM submarine cable systems

Submarine DWDM cable systems are designed for very high capacities at full loading, but initial loading could consist of few channels. We present a channel loading scheme that suppresses spectral hole burning impact in broadband systems. Such loading can be accomplished with few loading tones and allows for effective in-service upgrades.

Advantages of orthogonal polarization launch in a 6,500 km straight-line DWDM transmission experiment

We have presented a comparison of orthogonal and parallel polarization launch in a straight-line transatlantic DWDM transmission experiment. We observed more than 1 dB of Q-factor improvement when employing orthogonal launch. Our experimental results agree well with our simulator predictions.