We will examine progress in electrically pumped Metal-Insulator-Metal (MIM) waveguide laser devices. Such structures
allow the concentration of both electrically injected carriers and the optical mode into a gain region of just a couple of
tens of nanometers in size in two dimensions. We will show results from such waveguide devices, demonstrating the
presence of propagating optical modes in these devices. Another aspect of MIM waveguides is their use in Bragg
gratings to form distributed feedback lasers. Results will be shown from such Bragg grating devices and key issues in
their design discussed.
There has been considerable interest in nano-cavity lasers, both from a scientific perspective for investigating
fundamental properties of lasers and cavities, and also to produce smaller and better lasers for low-power applications.
Light confinement on a wavelength scale has been reported in photonic crystal nano-cavities. Even stronger light
confinement can be achieved in metallic cavities which can confine light to volumes with dimensions considerably
smaller than the wavelength of light. It was commonly believed, however, that the high losses in metals are prohibitive
for laser operation in metallic nano-cavities. Recently we have reported lasing in a metallic nano-cavity filled with an
electrically pumped semiconductor. Importantly, the manufacturing approach employed for these devices permits even
greater miniaturization of the laser. In particular Metal-Insulator-Metal (MIM) waveguides with dimensions well below
the diffraction limit can be fabricated using our techniques. Experimental results from such MIM waveguide lasers will
be presented. In theory it is shown that it is possible to reduce the semiconductor gain medium dimensions of these MIM
waveguide devices down to a few tens of nanometers in size. Finally, latest results for the fabrication of MIM type
waveguide devices will also be examined.
We present the results of a transmission experiment, over 110 km of field installed fiber, for an all-optical 160 Gb/s
packet switching system. The system uses in-band optical labels which are processed entirely in the optical domain
using a narrow-band all-optical filter. The label decision information is stored by an optical flip-flop, which output
controls a high-speed wavelength converter based on ultra-fast cross-phase modulation in a single semiconductor optical
amplifier. The packet switched node is located in between two different fiber sections, each having a length of 54.3-km.
The field installed fibers are located around the city of Eindhoven in the Netherlands. The results show how the all-optical
switch can effectively route the packets based on the optical information and that such packets may be
transmitted across the fiber with an acceptable penalty level.
We present some progress in the field of optical signal processing that could be utilized in all-optical packet switching. We demonstrate error-free 160 Gb/s optical wavelength conversion employing a single semiconductor optical amplifier. The gain recovery time of the semiconductor optical amplifier is greater than 90 ps. Assisted by an optical bandpass filter, an effective recovery time of 3 ps is achieved in the wavelength converter, which ensures 160 Gb/s operation. This optical wavelength converter can be controlled by a monolithically integrated optical flip-flop memory to route 80 Gb/s data-packets all-optically. The routing is realized without electronic control. The integrated optical flip-flop is based on two-coupled lasers, exhibits single-mode operation, has 35 dB contrast ratio between the states and switches state in about 2 ns. We demonstrate that the integrated flip-flop is able to control the optical wavelength converter up to 160 Gb/s. The system is capable of routing 80 Gb/s data packets with duration of 35 ns, separated by 15 ns of guard time.
We discuss how all-optical signal processing might play a role in future all-optical packet switched networks. We introduce a concept of optical packet switches that employ entirely all-optical signal processing technology. The optical packet switch is made out of three functional blocks: the optical header processing block, the optical memory block and the wavelength conversion block. The operation principle of the optical packet switch is explained. We show that these three functional blocks can be realized by using the nonlinearities of semiconductor optical amplifiers. Some technologies in these three functional blocks are described. The header processor is realized using a Terahertz Optical Asymmetric Demultiplexer. We also describe a header pre-processor to improve the extinction ratio of the header processor output. In the optical memory block, we show that an all-optical memory can be obtained by using two coupled lasers that form a master-slave configuration. The state of the optical memory is distinguished by the wavelength of the master laser. We extend the concept to an optical memory can have multiple states. In the wavelength conversion block, we demonstrate a 160 Gbit/s wavelength conversion using a single semiconductor optical amplifier in combination with a well-designed optical bandpass filter. The semiconductor optical amplifier has a gain recovery time
greater than 90 ps, which corresponds to a less than 20 GHz bandwidth for conventional wavelength conversion. We show that by properly using the optical bandpass filter, ultrafast dynamics in the semiconductor optical amplifier can be employed for wavelength conversion at ultrahigh bit-rates.
We discuss how all-optical signal processing might play a role in future all-optical packet switched networks. We describe a few approaches to optical header processing, all based on nonlinearities in a semiconductor optical amplifier. In first approach a SLALOM configuration is used. The second approach uses a Terahertz Optical Asymmetric Demultiplexer. We also describe a header pre-processor to improve the extinction ratio of the header processor output. The second functional block on which we focus is optical buffering. We show how all-optical signal processing technology can be used to route a packet into a fiber delay line and we describe a circulating optical loop based op optical technology.