Monolithic electro-optically modulated VCSEL suitable for radio over fibre applications to 20 GHz

An integrated EOM VCSELs is shown to offer high linearity (92dB/Hz 2/3 at 6GHz) and by extrapolation ∼90dB/Hz2/3 up to 20GHz. Successful modulation with IEEE 802.11g signals is demonstrated at 6GHz with a 12dB dynamic range. © 2011 Optical Society of America.

Picosecond pulse source for OTDM/WDM applications based on arrayed waveguide grating

A novel technique for high quality femtosecond pulse generation from a gain-switched laser diode by means of pulse compression and transformation in a compact nonlinear fiber device, based on a dispersion-imbalanced fiber loop mirror (DILM) is demonstrated. This source allows the generation of extremely high quality pulses as short as 270 fs on demand with strong suppression of pulse pedestals. Spectral filtering in arrayed waveguide grating (AWG) converts the device into a compact multiwavelength source of high-quality picosecond pulses for optical time division multiplexing/wavelength division multiplexing applications.

Quality enhancement of a WDM signal using dispersion-imbalanced loop mirror

The nonlinear filtering of a 10Gb/s data stream in a dispersion-imbalanced fibre loop mirror has been demonstrated over a wide spectral range of 28nm. A relative extinction ratio of - 30 dB for the cw background has been achieved across the whole spectral range.

Uncooled, 10Gb/s operation of two-contact InGaAsP lasers with low drive current

Uncooled, high-speed modulation of two-contact lasers is presented with ultra-low drive currents. Practical operation at 10Gb/s up to temperatures of 85°C and extinction ratios of 6dB are found for current swings which are less than 40% of conventional lasers.

High coupling in novel 2D-lattice distributed reflector laser gratings

It is shown that 2D lattice gratings, despite being placed outside the waveguide region, exhibit sufficiently strong coupling coefficients that optical modes rapidly couple transversely into the etched grating region, yielding high coupling coefficients of 270cm-1. This performance allows mode-hop-free lasing operation in DBR structures.

Fibre optics monitoring of clay cuttings and embankments along London's ring motorway

Although a wide range of techniques exist for slope monitoring, the task of monitoring slopes is sometimes complicated by the extensive nature and unpredictability of slope movements. The Brillouin optical time-domain reflectometer (BOTDR) is a distributed optical fiber strain measurement technology utilising Brillouin scattering. This method measures continuous strain along a standard optical fibre over a distance up to 10 km and hence has potential to detect deformations and diagnose problems along large sections of slopes and embankments. This paper reports the demonstration of BOTDR method for monitoring surface ground movements of clay cuttings and embankments along London's ring M25 motorway. A field trial investigating varying methods of onsite fibre optic installations was conducted. The surrounding ground was artificially moved by excavating a 3 m deep trench perpendicular to the instrumented sections. Results obtained from onsite installations after slope movement demonstrate a half-pipe covered fibre optic installed on wide (200mm) Tensar ™SS20 geogrid gives the most consistent recorded strain change profile. Initial conclusions suggest this method best represents induced ground motion at the surface and hence is recommended for implementation in future sitework. Copyright ASCE 2008.

Holographic mode-group division multiplexing

Specific fibre modes are deliberately excited in a few-mode and multimode fibre using holography. The same system is also used to demonstrate holography's ability to detect and route individual fibre modes. © 2011 Optical Society of America.

Aberration correction in Spatial Light Modulator based mode multiplexers

The Spatial Light Modulator in a mode demultiplexer is used to measure the aberrations of the system in which it is installed before applying aberration correction to improve the insertion loss and modal extinction ratios. © 2013 OSA.

Orthogonal multipulse modulation for 64 Gigabit Fibre Channel

Real-time orthogonal multipulse modulation is demonstrated at 56 Gb/s with transmission over 500 m of single-mode fiber. Up to 2 dBo power budget advantage is predicted relative to alternatives such as PAM4. © 2013 OSA.

Transmission of simultaneous 10Gb/s Ethernet and radio-over-fibre transmission using in-band coding

A technique using spectrum-shaping codes to create nulls in the baseband spectrum of an Ethernet signal, so that several RF signals can be inserted in-band, is demonstrated by simultaneous transmission of 10GbE and WCDMA signals. © 2013 OSA.

100 Gigabit Ethernet transmission enabled by carrierless amplitude and phase modulation using QAM receivers

Simulations have investigated single laser 100G Ethernet links enabled by CAP-16 using QAM receivers that not only lower significantly system timing jitter sensitivity but also outperform PAM and standard CAP in terms of power margin. © 2013 OSA.

Transient crosstalk in LCOS based WSS and a method to suppress the crosstalk levels

The origin of the transient crosstalk (TC) in a phase-only LCOS based WSS using a Fourier transform setup was investigated and identified. Two methods were proposed to reduce the TC by at least 5dB without the need to modify the optics or electronics in use. © 2013 OSA.

Aberration correction in spatial light modulator based mode multiplexers

The Spatial Light Modulator in a mode demultiplexer is used to measure the aberrations of the system in which it is installed before applying aberration correction to improve the insertion loss and modal extinction ratios. © 2013 OSA.

Orthogonal multipulse modulation for 64 gigabit fibre channel

Real-time orthogonal multipulse modulation is demonstrated at 56 Gb/s with transmission over 500 m of single-mode fiber. Up to 2 dBo power budget advantage is predicted relative to alternatives such as PAM4. © 2013 OSA.

Transmission of simultaneous 10Gb/s ethernet and radioover-fibre transmission using in-band coding

A technique using spectrum-shaping codes to create nulls in the baseband spectrum of an Ethernet signal, so that several RF signals can be inserted in-band, is demonstrated by simultaneous transmission of 10GbE and WCDMA signals. © 2013 OSA.