P.E. Barnsley’s research while affiliated with British Telecom and other places

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Publications (17)


Novel components for optical switching
  • Article

April 1993

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8 Reads

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3 Citations

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P.E. Barnsley

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J.D. Burton

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[...]

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H.J. Wickes

Advanced optoelectronic components based on semiconductor laser amplifier technology are showing enormous potential for a range of complex network functions. In this paper some current achievements in wavelength conversion, optical space and time switching and clock extraction are outlined. Extensions of the current technology offer a wide range of solutions to network problems.


NRZ format all-optical clock extraction at 3.2 Gbit/s using two-contact semiconductor devices

July 1992

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9 Reads

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15 Citations

Bit-error-ratio (BER) measurements have been demonstrated with all-optical clock recovery from a 3.2 Gbit/s NRZ sequence using two-contact semiconductor devices. A nonlinear optical amplifier generated the missing clock component in the NRZ modulation spectrum which then locked the output of a selfpulsating laser. BER measurements showed that the resulting clock signal was extremely pure and stable giving a 0.2 dB improvement in receiver sensitivity when compared to measurements using a clock from the transmitter. This type of optical clock recovery technique could have a major impact on future gigabit per second telecommunication systems.



Effects of spontaneous emission on hysteresis loops in bistable laser diodes

March 1992

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18 Reads

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5 Citations

It is shown theoretically that the widths of the hysteresis loops in absorptive bistable laser diodes are strongly dependent on the spontaneous emission coefficient. As a consequence, a correction is required to the method previously presented for determining the differential gain coefficient from experimental L-I plots. An analytical approximation for this correction is presented.


All-optical clock recovery from 2·5 Gbit/s NRZ data using selfpulsating 1.58 μm laser diode

February 1992

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3 Reads

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20 Citations

For the first time, all-optical clock extraction from 2.5 Gbit/s NRZ data is demonstrated using a two contact InGaAsP semiconductor selfpulsating laser diode (SP-LD) for what the authors believe to be the first time. The saturable absorber region of the device was doped with Zn ions to reduce the carrier lifetime such that strong selfpulsations at frequencies up to 4 GHz were obtained. Injection of a 10 mu W optical data signal at a wavelength approximately 15 nm lower than the lasing wavelength was sufficient to synchronise the selfpulsations to the incoming NRZ data stream. Similar effects were seen for RZ formated data. Such all-optical clock extraction techniques will find application in future multigigabit per second optical networks and for OEIC applications.


A 4 × 5 Gb/s Transmission System with All-Optical Clock Recovery

February 1992

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6 Reads

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33 Citations

IEEE Photonics Technology Letters

The authors demonstrate successful 5 Gb/s operation of an all-optical clock extraction circuit in a 20 Gb/s optical time division multiplexing OTDM system. An optical clock signal was obtained by synchronizing a self-pulsating 1.56 mu m laser diode to a 5 GB/s RZ data signal, demultiplexed from a 4*5 Gb/s OTDM transmission system. Synchronization was achieved for pseudo-random-bit sequences from 2/sup 7/-1 to 2/sup 31/-1. At 2/sup 7/-1 full system bit-error-ratio (BER) measurement on one of the 5 GB/s channels using the extracted optical clock for synchronization were made with no observed penalty over transmitter clock measurements. Such clock extraction techniques may be of great importance in a wide variety of telecommunications applications.< >


All-Optical Wavelength Switching from 1.3 μm to a 1.55 μm WDM Wavelength Routed Network: System Results

February 1992

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12 Reads

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17 Citations

IEEE Photonics Technology Letters

A wavelength converter based on a semiconductor nonlinear optical amplifier (NLOA) has been used to switch 155 MB/s data from 1.3 mu m into a 1.55 mu m WDM wavelength routed network. The data were converted to 1.56 mu m, one of the WDM system wavelengths, and transmitted over 63 km of step-index fiber. Bit-error-ratio measurements on the full system showed a 2 dB 10/sup -9/ receiver sensitivity penalty, demonstrating the usefulness of NLOAs as wavelength switches for future multiwavelength optical networks.< >


All-Optical Clock Recovery from 5 Gb/s RZ Data Using a Self-Pulsating 1.56 μm Laser Diode

November 1991

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26 Reads

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77 Citations

IEEE Photonics Technology Letters

All-optical clock extraction from 5 Gb/s RZ data is demonstrated using a two-contact InGaAsP semiconductor self-pulsating laser diode. The saturable absorber region of the device was doped with zinc ions to reduce the carrier lifetime in this region such that strong self pulsations at frequencies up to 5.2 GHz were obtained. Injection of a 10- mu W optical data signal at a wavelength close to one of the Fabry-Perot wavelengths was sufficient to synchronize the self pulsations to the incoming data stream. The measured 3-dB RF electrical bandwidth of the synchronized optical clock signal was 10 Hz, approximately the same as that of the electrical transmitter clock. Initial bit-error-rate measurements for 2/sup 7/-1 5 Gb/s data result in a 0.5-dB receiver sensitivity penalty when using the optical clock signal compared to the transmitter clock.< >


Method of determining differential gain coefficient for bistable semiconductor laser diodes

October 1991

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27 Reads

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8 Citations

Analytical expressions are obtained for the output power and bias current at switch on and switch off for absorptive bistable semiconductor laser diodes. Manipulation of these expressions yielded a simple analytical expression for the product of the carrier lifetime tau 2 and the differential gain sigma 2 in the absorber region in terms of the hysteresis width and the switch-off output power of the measured L-I characteristics. Experiments on a number of absorptive bistable devices indicated a mean value of 4.1*1016 cm2 for sigma 2.


Clock extraction using saturable absorption in a semiconductor nonlinear optical amplifier

October 1991

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7 Reads

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12 Citations

IEEE Photonics Technology Letters

A novel approach to clock extraction for non-return-to-zero (NRZ) formatted data is demonstrated using two contact semiconductor nonlinear optical amplifiers (NLOAs). The NLOA amplifies the transmitted data (fiber-fiber approximately 5 dB) and due to the absorptive nonlinearity, induced by bleaching a region of saturable absorption within the NLOA, an electrical clock component is generated at the absorber electrical contact. Narrow bandpass electrical filtering of the absorber contact electrical RF spectrum is all that is required in order to extract a stable clock signal. Bit-error-rate measurements at 155.6 Mb/s showed no receiver sensitivity penalty when using the NLOA extracted clock compared to the transmitter clock. Using quantum well material strong clock component generation has been achieved at modulation rates from < 100 Mb/s up to 5 Gb/s.< >


Citations (10)


... In optically transparent packet switching, it is necessary that the header replacement is carried out photonically [34]. Advances in photonic devices and components such as high-speed optical space switches, semiconductor optical amplifier (SOA) gate switches [9], [10], wavelength routing devices [35], [36], fast tunable lasers and filters [4], [12], [14], and wavelength converters [11], [12], [13], [16] have made it possible to construct photonic packet switch fabrics with a throughput in excess of their electronic counterparts [3]–[8]. Possible routing schemes for photonic packet switch fabrics include wavelength routing , broadcast-and-select routing, space-switch-based routing, and a combination of them. ...

Reference:

Photonic Packet Switching: An Overview
Novel components for optical switching
  • Citing Article
  • April 1993

... Among optical oscillating systems for CR, leading roles should be distributed to SP multi-sections lasers [148], [149], [117] and mode locked lasers [150], [151], [118]. The pulsating frequency of these lasers could be locked by injecting an optical data stream. ...

All-optical clock recovery from 2·5 Gbit/s NRZ data using selfpulsating 1.58 μm laser diode
  • Citing Article
  • February 1992

... The operation in the seminal work was demonstrated for a moderate data rate of 200 Mbit/s that was limited by the carrier lifetime of the SA region. When this region is doped with suitable dopant, such as Zn or N, and the SA region is suitably biased the carrier lifetime could be reduced and the operation was demonstrated for data rates of 5 Gbit/s [51][52][53][54], and 10 Gbit/s [55,56], respectively. The impact of SA biasing conditions for MLL performance has been studied in Ref. [57]. ...

NRZ format all-optical clock extraction at 3.2 Gbit/s using two-contact semiconductor devices
  • Citing Article
  • July 1992

... R eff is ignored, since the value of reflectivity of interface is too small to show effect on calculation of the cavity electric field distribution, [4 and 7]. Transmittance is included to model potential modal mismatch at the interfaces which it can result in optical scattering [7]. In addition to power flows in S-laser cavity, differential quantum efficiency (η d ) is derived. ...

Effects of spontaneous emission on hysteresis loops in bistable laser diodes
  • Citing Article
  • March 1992

... By using the appropriate bias current together with doping the various layers, the SOA overcomes the inherent absorption and loss of the active media and acts as an amplifier. Coating the input and output facets of the active waveguide with some anti-reflective material helps suppress feedback (Barnsley et al., 1990). ...

Ultra-low reflectivity broadband 1.5 mu m GaInAsP semiconductor optical amplifiers
  • Citing Article
  • July 1990

... These signal processing applications are of particular interest as directly performed by the same type of laser sources used in the transmission link. Although low-cost ways of performing wavelength conversion have been investigated, these solutions generally rely on the addition to the setup of an extra active component, usually an optical amplifier [6], [7]. In this paper, we propose a novel way of converting optical data at 1.3 m to 1.5 m using a commercially available C-band VCSEL. ...

All-Optical Wavelength Switching from 1.3 μm to a 1.55 μm WDM Wavelength Routed Network: System Results
  • Citing Article
  • February 1992

IEEE Photonics Technology Letters

... The operation in the seminal work was demonstrated for a moderate data rate of 200 Mbit/s that was limited by the carrier lifetime of the SA region. When this region is doped with suitable dopant, such as Zn or N, and the SA region is suitably biased the carrier lifetime could be reduced and the operation was demonstrated for data rates of 5 Gbit/s [51][52][53][54], and 10 Gbit/s [55,56], respectively. The impact of SA biasing conditions for MLL performance has been studied in Ref. [57]. ...

A 4 × 5 Gb/s Transmission System with All-Optical Clock Recovery
  • Citing Article
  • February 1992

IEEE Photonics Technology Letters

... Self-sustained pulsations or self-pulsations occur when there is a repetitive firing to a strong stimulus [1]. Selfpulsation has applications in spectroscopy and optical computing [2,3]. A variety of integrated devices has this behavior and tends to fall into two categories: semiconductor lasers or nonlinear optical cavities. ...

All-Optical Clock Recovery from 5 Gb/s RZ Data Using a Self-Pulsating 1.56 μm Laser Diode
  • Citing Article
  • November 1991

IEEE Photonics Technology Letters

... Optical clock extraction from nonreturn-to-zero (NRZ) format data is a rather difficult task due to the absence of discretely separated clock components, as occurs instead in the return-to-zero (RZ) format. Techniques have been proposed that are based either on conversion schemes from the NRZ format to pseudoreturn-to-zero (PRZ) [1,2], or on nonlinear effects in semiconductor optical amplifiers (SOAs) [3,4]. In particular, self-phase modulation in SOAs has been exploited for optical clock recovery for both RZ and NRZ data [5], as well as for optical enhancement of the clock-to-data suppression ratio of NRZ data [6]. ...

Clock extraction using saturable absorption in a semiconductor nonlinear optical amplifier
  • Citing Article
  • October 1991

IEEE Photonics Technology Letters

... Multi-electrode is often used in optical bistability lasers [2], 1.3 to 1.5μm wavelength conversions [3] and SOAs used as both detectors and optical amplifiers [4]. In this paper, based on the distribution rules of carrier concentration and photon density along the cavity of SOA, we propose a new scheme to control the gain spectrum by multi-electrode SOA. ...

Wavelength Conversion from 1.3 to 1.55 μm Using Split Contact Optical Amplifiers
  • Citing Article
  • April 1991

IEEE Photonics Technology Letters