Adjustable dispersion equaliser for 10 and 20 Gbit/s over distancesup to 160 km

A novel chirped fibre grating has been used to equalise the dispersion of 10 and 20 Gbit/s data over 80 and 160 km standard fibre at 1557 nm. Unlike earlier fixed value dispersion equalisers, the grating chirp is adjustable, enabling the same device to be used for different fibre lengths and bit rates     

Performance improvement by initial phase modulation in 20 Gbit/ssoliton-based RZ transmission with periodic dispersion compensation

Transmission performance has been greatly improved by employing bit-synchronous phase modulation to source pulses in 20 Gbit/s soliton-based RZ transmission experiments. The tolerable window for both repeater output power and signal wavelength, for 9000 km transmission, was doubled with phase modulation     

Multi Gbit/s bit parallel WDM transmission using dispersion managedfibers

This paper demonstrates the feasibility of a bit parallel WDM (BP-WDM) system using dispersion managed fibers. An expression for the total bit skew as a function of the fiber dispersion and system bandwidth is derived and compared with experimental results. A 4 bit×10 Gbit/s-per bit BP-WDM transmission experiment over 30 km DMF is used and an aggregate bite rate×distance product of 1.2 Tbit/s-km is obtained. The total bit skew of the system is reduced to one half of the bit period. We believe that systems using BPWDM will be useful for computer interconnects in high-speed parallel systems and ring networks     

Nonlinear transmission of 20 Gbit/s optical time-division-multiplexed data, over 205 km of dispersion shifted fibre

Nonlinear pulse compression has been used to achieve transmission beyond the linear dispersion limit for 20 Gbit/s optical time-division-multiplexed data. Error free system operation has been achieved over an operating wavelength range of 10 nm above the wavelength of zero dispersion, in the anomalous dispersion regime.<>     

20 Gbit/s no-chirp intensity modulation by DPSH-IM method and its fibre transmission through 330 ps/nm dispersion

20 Gbit/s intensity modulation has been achieved by the authors' original method of DPSH-IM (direct phase shift and self-homodyne intensity modulation). The drive voltage was only 1.6 V when matched with 50 Omega . The pseudorandomly modulated lightwave showed a high extinction ratio and a narrow spectrum width without wavelength chirping. Chromatic dispersion of 330 ps/nm caused little waveform degradation.<>     

Performance of non-fibre based dispersion compensation for long-haul 10.7 Gbit/s DWDM transmission

Non-fibre based in-line dispersion compensation is employed to achieve long-haul transmission of 80 channels at 10.7 Gbit/s bit rate over 1200 km of LEAF fibre. Average system margins of more than 4 dB and small transmission are demonstrated. The additional penalty incurred by the periodic nature of the dispersion compensator is assessed.     

Unrepeatered transmission of an OTDM 40 Gbit/s signal over 110 kmusing a dispersion-adjustable PLC delay equaliser

Using a dispersion-adjustable PLC delay equaliser, unrepeatered 110 km transmission of a 40 Gbit/s PRBS signal over both positive and negative dispersion fibre has been successfully demonstrated for the first time     

Straight-line soliton data transmission at 20 Gbit/s beyondGordon-Haus limit

Soliton data signals at 20 Gbit/s have been successfully transmitted over 3000 km with the use of soliton control by synchronous modulation and optical filters. The installation of only one simple modulator makes it possible to extend the maximum transmission distance from 2300 km (without soliton control) to 3000 km which is clearly beyond the Gordon-Haus limit     

40 Gbit/s CSRZ-DPSK transmission system with signed online chromatic dispersion detection

A chromatic dispersion measurement scheme based on arrival time detection, an active interferometer phase stabilisation, and a standard clock-and-data recovery circuit are used in this 40 Gbit/s carrier-suppressed return-to-zero differential phase shift keying system. Chromatic dispersion measurement noise is 100 fs/nm.     

20 Gbit/s soliton transmission over 19 Mm using sliding-frequencyguiding filters

20 Gbit/s time-polarisation multiplexed solitons have been transmitted over 19 Mm in a recirculating loop with a 35 km amplification span using the sliding-frequency guiding filter soliton control technique. Soliton energy and sliding rate margin measurements are reported for 10 Mm     

Dispersion-supported transmission at 20 Gbit/s over 53 km standardsinglemode fibre

The optical transmission of 20 Gbit/s signals over a record distance of 53 km standard nondispersion-shifted singlemode fibre (SMF) without optical dispersion compensation has been demonstrated successfully using a directly modulated MQW DFB laser operating at 1544 nm     

Subband equaliser for chromatic dispersion of optical fibre

An oversampled subband equaliser is designed for chromatic dispersion of singlemode optical fibre. The signal of each subband is equalised individually and delayed to align with other subbands. From simulation, the overall number of equaliser taps is approximately reduced by the upsampling ratio.     

1.52 Tbit/s OCDM/WDM (4 OCDM×19 WDM×20 Gbit/s)transmission experiment

1.52 Tbit/s OCDM/WDM (4 OCDM×19 WDM×20 Gbit/s) transmission based on simultaneous multi-wavelength optical encoding of a single supercontinuum source is experimentally demonstrated with 0.4 bit/s/Hz spectrum efficiency     

Automatic selective equaliser for telephone facsimile transmission

A simple automatic equaliser designed especially for G2 as well as G1 facsimile signals received through carrier links is presented. The new method requires no additional signal, utilising only a phasing signal to fix the equalising parameters by detecting the symmetry in the received step response.     

Convergence of adaptive equaliser for data transmission

A faster algorithm is proposed to determine the optimal tap setting of transversal delay-line equalisers which use the criterion that the mean-square error is minimum. The convergence of this algorithm is compared with the well known steepest-descent algorithm.     

Distance limits of 10 to 20 Gbit/s FSK transmission on standardfibre

A simple analysis is performed on an FSK transmission system using a high FM efficiency, high bandwidth DFB laser as a simple DFB transmitter and an FM/AM converter as an optical signal processor. It shows that optimum optical processing pushes the transmission limits to 150 km at 10 Gbit/s and to 40 km at 20 Gbit/s     

20 Gbit/s soliton transmission using alternating dispersionarrangement in standard fibre systems

An alternating dispersion arrangement is proposed for soliton systems with dispersion compensation to improve soliton stabilisation. A transmission experiment at 20 Gbit/s over 2600 km long singlemode fibre was successfully demonstrated by employing this novel dispersion arrangement     

Demonstration of sliding-filter-controlled soliton transmission at20 Gbit/s over 14 Mm

Soliton transmission of a 20 Gbit/s time/polarisation multiplexed signal over 14 Mm path in a recirculating loop with 46.3 km amplification span has been demonstrated using the sliding-filter soliton control technique. Demultiplexing was achieved by using a polarisation-insensitive electroabsorption modulator     

Integrated space-time equaliser for DS/CDMA receiver with unequalreduced lengths

An integrated space-time equaliser is proposed for direct sequence code division multiple access (DS/CDMA) receivers. A significant reduction in mean square error over that possible with the previous equalisers cascaded space-time reduced-length receiver is obtained with the integrated architecture. In addition, the use of unequal reduced lengths between array elements can significantly reduce the complexity without significantly reducing the performance     

20 Gbit/s long distance transmission using a 270 photon/bit opticalpreamplifier receiver

A 200 km nonrepeatered transmission experiment and a 400 km transmission experiment using three in-line amplifiers are carried out at 20 Gbit/s by using a simple but highly sensitive optical preamplifier receiver based on a 0.98 μm LD-pumped EDFA. High sensitivity of -31.6 dBm (270 photon/bit) at 20 Gbit/s is obtained