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This paper describes the advantages that the introduction of photonic integration technologies can bring to the development of photonic-enabled wireless communications systems operating in the millimeter wave frequency range. We present two approaches for the development of dual wavelength sources for heterodyne-based millimeter wave generation realized using active/passive photonic integration technology. One approach integrates monolithically two distributed feedback semiconductor lasers along with semiconductor optical amplifiers, wavelength combiners, electro-optic modulators and broad bandwidth photodiodes. The other uses a generic photonic integration platform, developing narrow linewidth dual wavelength lasers based on arrayed waveguide gratings. Moreover, data transmission over a wireless link at a carrier wave frequency above 100 GHz is presented, in which the two lasers are free-running, and the modulation is directly applied to the single photonic chip without the requirement of any additional component.

A 2-D Hermite-Gaussian square launch is demonstrated to show improved systems capacity over multimode fiber links. It shows a bandwidth improvement over both center and offset launches and exhibits ±5 µm misalignment tolerance.

A novel Quantum Dot monolithically integrated 1×8 switch is shown to provide robust routing of data at 10Gb/s modulation rates. Two cascaded switches providing, 1×64 functionality, operate with a power penalty of only 0.9dB.

An integrated 1300 nm QD mode-locked narrow stripe MOPA is shown to generate 10.5 ps Fourier transform limited pulses at 20 GHz. The pulse train has an average power of 46.4 mW and peak powers exceeding 0.31 W.

10Gb/s error-free operation of the first monolithic 16×16 quantum well semiconductor optical amplifier switch is demonstrated. The switch has a 2dB facet-to-facet gain and a minimum power penalty of 2.5dB.

A scalable photonic interconnection network architecture is proposed whereby a Clos network is populated with broadcast-and-select stages. This enables the efficient exploitation of an emerging class of photonic integrated switch fabric. A low distortion space switch technology based on recently demonstrated quantum-dot semiconductor optical amplifier technology, which can be operated uncooled, is used as the base switch element. The viability of these switches in cascaded networks is reviewed, and predictions are made through detailed physical layer simulation to explore the potential for larger-scale network connectivity. Optical signal degradation is estimated as a function of data capacity and network size. Power efficiency and physical layer complexity are addressed for high end-to-end bandwidth, nanosecond-reconfigurable switch fabrics, to highlight the potential for scaling to several tens of connections The proposed architecture is envisaged to facilitate high-capacity, lowlatency switching suited to computing ystems, backplanes, and data networks. Broadband operation through wavelength division multiplexing is studied to identify practical interconnection networks scalable to 100 Gbits/s per path and a power consumption of the order of 20 mW/ ??Gbits/s?? for a 64 ??64 size interconnection network.

Optical interconnects are being considered for short link data networks as a solution enabling higher aggregate bit rates and lower power consumption. For short link length interconnects, as used in chip to chip interconnects, internal system backplanes and inter-system interconnects such as blade server backplanes, storage area networks and processing clusters, requirements are quite different to those for long distance telecommunications systems. Low power consumption, latency, and size become important criteria in addition to ultra high bandwidth. In order to achieve the projected ultra high capacity and low latency needs, we are considering optical switching fabrics. The optical switch, however, brings significant changes to the interconnect architecture in terms of how routing decisions are made and how contention resolution is managed. We discuss these issues and present our results for a multiwavelength optically switched interconnect.

We propose a device based on self-induced phase shifting to create a non-linear optical transfer function with a single optical access. The device is designed around the Nonlinear-Optical Loop Mirror (NOLM) principle. The device is a loop formed by four SOAs with a splitter/recombiner at one of the junctions for optical access. The device also includes a mirror inside one of the SOAs such that part of the light is transmitted around the loop and part is reflected. The dimensions of formed loop are kept below 4mm (1mm/SOA) to the requirement for integration. It is assumed the loop is based on a standard ridge waveguide design with InGaAsP/InGaAs quantum wells yielding a refractive index of 3.88. Also, the width of the waveguide is kept constant at 2μm to ensure single-moded operation. We present simulations results obtained with VPITransmissionMakerTM from VPIPhotonics. The software allows the simulation of optical modules such as Lasers, SOAs, Bragg Grating. The SOA and Laser modules exploit on the Transmission Line Laser Model (TLLM) model for solving the standard laser rate equations. For the Multi-Quantum Wells (MQW) SOAs, another set of equations are used to model the effects of carriers entering and exiting the quantum wells. The model is used to explore the tunability of the design and manufacturing parameters for optimal performance of the non-linear optical loop mirror. Design parameters include the size of the loop, drive current of each SOA, position and reflectivity of the mirror, number and size of the quantum wells and separate confinement height. To provide an efficient way of comparing different values for a given parameter, three figures of merits are chosen. The first one is the input dynamic range of the device in its current configuration, which corresponds to the area of the transfer function where the input signal will experience regeneration. The second parameter is the peak to trough ratio corresponding to the maximum possible output swing i.e. the maximum point of the transfer function less its corresponding minima. The final parameter named the regeneration slope is the division of the peak to trough ration by the input dynamic range. The particularity of this loop is the mirror etched into one of the active waveguides to create self-induced phase shifts leading to non-linear transfer functions with a single optical input. Optimisation is explored for various design parameters that would need to be decided prior to manufacturing such a device. It is believed that such optimisation can provide a way to create all-optical signal processing devices created for a single application.

We report 7 GHz cut-off frequency, 2.5 and 5Gb s(-1) eye pattern measurements upon direct modulation of 1.3 mum quantum dot lasers grown without incorporating phosphorus in the layers. Passive mode-locking is achieved from very low frequencies up to 50 GHz and hybrid mode-locking is achieved up to 20 GHz. The minimum pulse width of the Fourier-limited pulses at 50 GHz is 3 ps, with an uncorrelated timing jitter below 1 ps. The lasers are optimized for high frequency operation by a ridge waveguide design that includes etching through the active layer and ridge widths down to 1 mum. The far-field shape for 1 mum is close to circular with a remaining asymmetry of 1.2.

Highly localised carbon doping is demonstrated within the active region of strained InGaAs/GaAs MQW lasers. As predicted by numerical beam propagation simulations, the smaller linewidth enhancement factor arising from the combination of strain and p-doping leads to reduced filamentation in tapered laser structures, as compared to devices fabricated from otherwise identical epilayer structure containing undoped active regions.