Transmission experiments through 101 km and 84 km of single-mode fibre at 274 Mbit/s and 420 Mbit/s

Four transmission experiments through low-loss single-mode optical fibre at 1.3 ?m have been performed at 274 Mbit/s and 420 Mbit/s with different objectives. The first demonstrates transmission through 101 km of single-mode fibre at 274 Mbit/s with negligible dispersion penalty. The second experiment at 274 Mbit/s and 84 km uses only components suitable for use in an undersea cable system. Two additional experiments, both at 420 Mbit/s, accomplish a bitrate × distance product of 35 GHzkm with 84 km of fibre and show no dispersion penalty with 63 km and 2.4 ps/km nm dispersion.     

1.5 m optical transmission experiments using very low-loss single-mode fibres

By using an InGaAsP semiconductor laser emitting at 1.5 ?m, where silica fibre loss is at a minimum, single-mode fibre transmission experiments were successfully carried out at 100 Mbit/s with about 30 km repeater spacing, 400 Mbit/s transmission characteristics using 20 km fibres are also reported.     

1.3 ?m bidirectional optical transmission over 31 km of installed single-mode fibre using optical couplers

Results are reported of 1.3 ?m bidirectional optical transmission over 31 km of installed cabled fibre at transmission rates of 34?650 Mbit/s using fused biconical tapered couplers manufactured at BTRL. With the introduction of 6 dB extra path loss it is possible to double the system capacity incurring only a small additional penalty at 34 and 140 Mbit/s and no other penalty at 320 and 650 Mbit/s.     

1 Gbit/s transmission experiment over 101 km of single-mode fibre using a 1.55 ?m ridge guide C3 laser

Using a cleaved-coupled-cavity (C3) ridge guide laser which oscillates in a single longitudinal mode at 1.55 ?m wavelength, we report the first lightwave transmission experiment exploying single-frequency lasers at speeds above 500 Mbit/s. We have achieved digital transmission with a bit-error rate of 2 × 10?10 at 1.0 Gbit/s over 101 km of single-mode fibre. This represents a record for the length of unrepeatered optical transmission for bit rates greater than 500 Mbit/s. Evidence for an error-rate floor, presumably due to residual partition noise, is observed. No such floor was observed in an 84 km?1 Gbit/s experiment using the same C3 laser.     

Bidirectional fibre-optical transmission using a multiple-quantum-well (MQW) modulator/detector

We demonstrate a simple architecture for bidirectional optical fibre transmission which uses an MQW device as both modulator and photodetector. We achieved transmission of 50 Mbit/s and 600 Mbit/s in both directions over one 3.34 km-long single-mode fibre at 860 nm wavelength. Coherent Rayleigh interference was found to be a limiting factor in single-source bidirectional systems.     

2.26 Gbit/s optical transmission system with 5B6B line coding

A 2.26 Gbit/s optical transmission system featuring four inputs at 565 Mbit/s and binary 5B6B line coding has been realised. The technical feasibility has been tested with various laser diodes on both conventional and dispersion flattened single mode fibre.<>     

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.<>     

WDM experiment using 1300/1500 nm dual-wavelength LED for single-mode fibre transmission systems

A wavelength-division-multiplexing transmission experiment using a 1300/1500 nm dual-wavelength LED modulated at 140/560 Mbit/s over 10 km of single-mode fibre has been demonstrated. This dual-LED device has a 9 ?m emitter spacing between the active facets with a coupling loss of 2.3 dB through a lens/fibre coupler. The chromatic dispersion penalty for the 1500 nm channel at 560 Mbit/s was about 6-5 dB and the electrical crosstalk penalty was 2.5 dB.     

Dispersion-free single-mode fibre transmission experiments up to 1.6 Gbit/s

Long-span single-mode fibre transmission experiments at 1.3 ?m have been refined toward higher digit rate and longer fibre span. Error-rate against receiving optical level characteristics showed that optical power penalties at 100 Mbit/s, 1.2 Gbit/s and 1.6 Gbit/s are negligible, even after 30 km, 23 km and 13 km fibre transmission, respectively.     

Wavelength-division-multiplexed optical transmission system with single-mode fibre and a dual-wavelength hybrid laser light source

Wavelength-division-multiplexed optical fibre transmission over a 45km single-mode fibre using a hybrid dual-wavelength InP CSBH laser light source emitting at 1.3 ?m and 1.5 ?m has been demonstrated. This simple and economic system provides two distinct optical data channels without requiring electronic or optical multiplexing. Optical crosstalk was unobservable while operating the separate optical channels at 1.5 Gbit/s and 90 Mbit/s, respectively. The use of a single light source eliminates multiple fibre-to-source alignments, reducing transmitter packaging costs.     

Transmission of 622 Mbit/s spectrum-sliced WDM channel over 60 kmof nondispersion-shifted fibre at 1550 nm

The transmission of a spectrum-sliced WDM channel at 622 Mbit/s over 60 km of nondispersion-shifted fibre using an optical bandwidth of only 0.23 nm is reported. This is the highest single channel bit rate-length product (40 Gbit/s·km) and smallest channel bandwidth reported to date for spectrum-sliced WDM systems. The bit error rate performance is theoretically predicted and experimentally confirmed and limits on the bit rate-length products of spectrum-sliced WDM channels using nondispersion-shifted fibre in the 1550 nm window are given     

120 Mbit/S QPSK data and multi-channel TV transmission over 13 kmfibre to a 60 GHz mobile radio link using an electroabsorption modulatoras a transceiver

A broadband analogue fibre-radio millimetre-wave system has been constructed. The system is capable of downstream 120 Mbit/s QPSK data transmission over 13 km of fibre and onward radio transmission at 60 GHz. Simultaneous transmission of downstream data, broadcast video and upstream data over fibre is also incorporated using sub-carrier multiplexing     

Wavelength-tunable 16 optical channel transmission experiment at 2Gbit/s and 600 Mbit/s for broadband subscriber distribution

Reports a 16 optical-channel single-mode fibre transmission experiment based on dense-WDM and tunable-etalon channel selection. Experiments at 2 Gbit/s and 600 Mbit/s over 10 km of single-mode fibre show little crosstalk penalty when the optical channel spacing is 2 nm. The system architecture is useful for high-capacity broadband subscriber distribution     

102 km unrepeatered monomode fibre system experiment at 140 Mbit/s with an injection locked 1.52 ?m laser transmitter

An experiment has been performed over 102 km of low-loss monomode fibre at 140 Mbit/s using an injection-locked source at 1.52 ?m. The experiment showed that long-haul unrepeatered transmission is possible with nonzero-dispersion shifted fibre using narrow-linewidth laser transmitters.     

Bidirectional optical transmission using polarised light waves

Bidirectional optical transmission using polarised light waves is demonstrated for the first time. Transmission of 100 Mbit/s signals over 13.6 km of polarisation-maintaining fibre occurs simultaneously in both directions at 1.55/?m. LD transmitters with polarisation-maintaining fibre pigtails, polarisation-maintaining fibre couplers, fibre polarisers and Ge-APD receivers are used.     

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.<>     

34 Mbit/s optical fibre transmission system experiment at a wavelength of 2.4 ?m

Data transmission at 34 Mbit/s has been performed over a fluoride glass fibre at a wavelength close to the 2.55 ?m minimum-loss wavelength of the fibre, using an externally modulated He-Ne laser and a graded-composition GaInAs photodiode with spectral response optimised for 2.55 ?m operation.     

Demonstration of 2.488 Gbit/s transmission on the UK—Channel Islands No 7 submarine cable system

The recently-installed UK—Channel Islands No 7 cable system is a 132 km unrepeatered, twelve optical fibre, 140 Mbit/s system. In February the cable was used for a series of tests to demonstrate new transmission and receiver equipment developed at British Telecom Research Laboratories (BTRL). The paper describes first the use of erbium fibre power amplifiers to achieve two-way transmission over the system at 2.488 Gbit/s, and then the testing of a novel semi-ruggedised laser PIN receiver.     

Single-laser high-selectivity bidirectional transmission system for local-area-network applications

Bidirectional transmission at 90Mbit/s over 30 km of fibre using a single laser source is demonstrated. At the subscriber end, a narrowband resonant optical amplifier serves not only as amplifier, but also as detector, modulator and optical filter. The coherent Rayleigh noise, encountered in previous single-laser bidirectional systems, is eliminated by using a subcarrier modulation scheme. The demonstrated capacity is more than an order of magnitude improvement over similar systems.     

Experimental demonstration of a three channel WDM system over 110 km using superluminescent diodes

The experimental demonstration of a three channel WDM (wavelength division multiplexer) system over 110 km of single mode optical fibre at 140 Mbit/s using a high power superluminescent diode and an erbium fibre amplifier is reported.<>