Performance of Pr-doped fluoride fibre amplifier for multichannel AM-VSB transmission

The system performance of a Pr-doped fluoride fibre amplifier was examined for multichannel AM-VSB video signal transmission for the first time. For a CNR of 51 dB, a loss budget of 15.1 dB was obtained with the amplifier, and for a CNR of 46 dB, the loss budget was expanded to 20.1 dB.<>     

Video distribution system with 40 AM-VSB channels and 22 dB link budget

By using AM-VSB transmission, an erbium-doped fibre power amplifier, and a low-noise receiver, a video distribution system attains a 22 dB link budget for 40 channels.<>     

Improved performance of subcarrier multiplexed multichannel AM-VSBvideo signal transmission using Pr3+-doped fluoride fibreamplifier

The performance of 40 channel AM-VSB video signal transmission using a Pr³⁺-doped fluoride fibre amplifier (PDFA) was examined. The PDFA improves the loss budget by 10 dB for 52 dB CNR, and distortion levels almost satisfy the CATV trunk line specifications. The video quality degradation after PDFA amplification was `imperceptible' in subjective tests     

Noise characteristics of Pr/sup 3+/-doped fluoride fibre amplifier

The noise characteristics of a Pr/sup 3+/-doped fluoride fibre amplifier (PDFFA) are reported for the first time. Using an amplifier with a 20 dB gain, a noise figure of 3.2 dB is obtained at a wavelength of 1.31 mu m at an amplified output signal power between -18 and -2 dBm. However, it is observed that the noise figure increases when the signal wavelength is above 1.32 mu m.<>     

Long span coherent transmission with erbium ytterbium doped fibre power amplifier over a 70 dB loss budget

A combination of a high power Er/Yb fibre optic amplifier and a coherent transmission system are used to achieve very large optical link loss budgets of 70 dB at 167 Mbit/s and 67 dB at 622 Mbit/s. A transmit power of +18.2 dBm was launched into low loss optical fibre without evidence of stimulated Brillouin scattering.<>     

Field demonstration of coherent transmission system with diode-pumped erbium doped fibre amplifiers

Reports a field demonstration of 622 Mbit/s DPSK and FSK coherent transmission over 200 km of installed single mode fibre. Diode-pumped erbium doped fibre amplifiers were used as both power amplifiers and repeaters. System loss budgets of more than 68 dB were achieved with an intermediate amplifier repeater gain of 16.5 dB. Both systems incorporated fully automated endless polarisation control.<>     

Optical time-division multiplexed transmission at 8 Gbit/s using single laser and semiconductor optical power amplifier

The authors report transmission over 57 km of single-mode fibre in a two-channel, 8 Gbit/s optical time-division multiplexed system experiment using a transmitter with a single laser and a semiconductor optical power amplifier at the transmitter output. The amplifier operates with a net gain of 11.5 dB, which corresponds to 0.8 dB gain compression, and a fibre coupled output power of +6 dBm. The amplifier facet output power for which the gain is compressed by 3 dB is +13 dBm. The experimental system uses neither an isolator nor an optical filter.<>     

High output power from an efficient praseodymium-doped fluoridefiber amplifier

A praseodymium doped fluoride fiber amplifier (PDFFA) exhibiting efficient operation in both the large- and the small-signal regimes is described. The amplifier, based on a high NA fluoride fiber, exhibited a maximum small-signal gain of 29 dB and a low-pump small-signal. efficiency of 0.13 dB/mW. In the saturated regime a maximum output power of 212 mW was achieved. In this format, the signal-out versus pump-in characteristic, exhibited a slope efficiency of 30%, representing the most efficient conversion from pump to signal yet reported. Detailed spectral characterization reveals small-signal gain in excess of 20 dB over a wavelength range of almost 50 nm and in excess of 100 mW of saturated output available over a 30-nm wavelength range     

Ultra-wideband optical amplification with 3 dB bandwidth of 65 nmusing a gain-equalised two-stage erbium-doped fibre amplifier and Ramanamplification

A 3 dB gain-reduction bandwidth up to 65 nm (1549-1614 nm) is achieved using a two-stage erbium-doped fibre amplifier, together with an intermediate equaliser and Raman amplification in the transmission fibre     

Inline frequency-non-degenerate phase-sensitive fibre parametric amplifier for fibre-optic communication

Error-free transmission of 2.5 Gbit/s data over 60 km of dispersion-compensated standard single-mode fibre is demonstrated by using an inline phase-sensitive fibre-parametric amplifier and double-sideband data modulation format. The power penalty for the phase-sensitive amplifier was found to be <0.5 dB compared to back-to-back for bit-error-rate >10/sup -6/ and <2 dB compared to that for an equivalent phase-insensitive fibre-parametric amplifier of the same gain.     

Fibre transmission of 10 Gbit/s signals following wavelengthconversion using a travelling-wave semiconductor optical amplifier

The wavelength of an intensity-modulated signal at 10 Gbit/s was translated from 1546 to 1531 nm using cross gain-compression in a semiconductor optical amplifier. The shifted signal was transmitted with less than 1 dB penalty over a 121 km span of dispersion-shifted fibre with two in-line amplifiers. A dispersion penalty of nearly 2 dB is measured for transmission of 6 Gbit/s data over 20 km conventional fibre     

1.7 Gbit/s transmission over 165 km of dispersion-shifted fibreusing spectrum-sliced fibre amplifier light source

The authors have demonstrated 1.7 Gbit/s transmission over 165 km of dispersion-shifted fibre using a spectrum-sliced fibre amplifier light source. To the authors' knowledge, this represents the largest bit-rate distance product (280 Gbit/s km) ever demonstrated using an incoherent light source. The dispersion penalty was very small (~0.3 dB) even at a wavelength 10 nm away from the dispersion-zero wavelength of the fibre     

Unrepeatered 2.4 Gbit/s transmission experiment over 250 km of step-index fibre using erbium power amplifier

An erbium power amplifier is used to give a system launch power in excess of +20 dBm. In conjunction with an FSK modulation technique this allows unrepeatered transmission over 250 km of step-index fibre with a loss of 50 dB and a total dispersion of 3930 ps nm/sup -1/.<>     

Ultra-long-distance fbg sensor system based on spectrum-limited fourier domain modelocking fibre laser with raman pumps

A novel ultra-long-distance (up to 76 km) fibre Bragg grating (FBG) sensor system based on a spectrum-limited Fourier domain modelocking fibre laser is proposed. Raman pumps are employed to form a Raman amplifier to compensate the transmission loss of the long fibre and ensure ultra-long-distance sensing. Strain sensing based on such an ultra-long-distance FBG sensor system is demonstrated with a signal-to-noise ratio over 22 dB and a sensitivity of 1.03 pm/muepsiv in the wavelength domain or 18.3 ns/muepsiv in the time domain.     

10 Gbit/s high performance MQW tandem modulator for solitongeneration and coding

Soliton generation and coding are obtained using a novel, and simple tandem integrated electroabsorption (EA) MQW modulator structure. Negligible electrical crosstalk (<40 dB) is obtained due to the integration between the modulators, of an optical amplifier based on the same active layer. This also allowed a very low fibre to fibre insertion loss of 9 dB. The device was operated at 10 Gbit/s     

400 Mbit/s optical heterodyne DPSK system experiment with inline1.5 μm amplifiers

Reports a 400 Mbit/s differential phase shift keying (DPSK) heterodyne optical transmission system experiment using two inline packaged resonant type amplifiers. The optical amplifier gave a 14.5 dB net gain from fibre to fibre at λ=1.488 μm with no significant system penalty     

Power budget optimisation of WDM network with MSCM control

The authors have experimentally demonstrated a 28.7 dB power budget for simultaneous transmission of 2.5 Gbit/s/node payload data and 80 Mbit/s/node control channels using the multichannel subcarrier multiplexing (MSCM) signalling technique. The power budget is sufficient to support a 234 node MSCM-WDM network with 2.5 Gbit/s/node 10 km radius coverage and 0.25 dB/km fibre attenuation with 0.45 dB/km attenuation, the network can support up to 93 nodes     

L-band Er3+-doped fluorophosphate glass-fibre amplifier

The first L-band EDFA to employ fluorophosphate glass as the host glass material has been realised. The lowest fibre loss yet reported for fluorophosphate glass fibre of 0.7 dB/m is achieved. The amplifier achieved a flat gain with an average value of 21.7 dB in the L-band.     

Ultra-wide-band Raman amplifier using tellurite and silica fibres

An extremely large seamless gain-bandwidth of 135 nm (1497-1632 nm) with a minimum gain of 22.8 dB is achieved with a novel hybrid tellurite/silica fibre Raman amplifier. The amplifier is used successfully as a pre-amplifier in a WDM transmission experiment     

L-band erbium-doped fibre amplifier with clamped- and flattened-gain using FBG

A gain clamped long wavelength band erbium-doped fibre amplifier (L-band EDFA) based on a ring laser cavity is demonstrated using a fibre Bragg grating (FBG) at the output end of the amplifier. This new design provides a good gain clamping as well as a gain flattening. The gain is clamped at 16.9 dB with gain variation of less than 0.1 dB from input signal power of -40 to -18 dBm by setting the VOA=5 dB. Also, the amplifier has the flattest gain spectrum at VOA=5. The gain variation is less than 1.0 dB within the wavelength range from 1570 to 1600 nm. This gain clamped amplifier also can support a 12 channel WDM system.