Mutual optical injection in coupled DBR laser pairs

We report an experimental study of nonlinear effects, characteristic of mutual optical coupling, in an ultra-short coupling regime observed in a distributed Bragg reflector laser pair fabricated on the same chip. Optical feedback is amplified via a double pass through a common onchip optical amplifier, which introduces further nonlinear phenomena. Optical coupling has been introduced via back reflection from a cleaveended fibre. The coupling may be varied in strength by varying the distance of the fibre from the output of the chip, without significantly affecting the coupling time. © 2008 Optical. Society of America

Photonic-Enabled Microwave and Terahertz Communication Systems

Abstract: An optical heterodyne technique for generating millimetre-wave and THz carriers with high spectral purity and low phase noise is described, for application to Gb/s wireless communications systems. Progress on key integrated optical components is reported. Introduction Microwave photonics research [1] has found applications in areas as diverse as electronic warfare and medical imaging, and the development of wireless-over-fibre systems for distribution of cellular radio and other wireless signals within large buildings and other areas where coverage from conventional hill-top sites is poor, has proved to be of considerable commercial importance, with sales of systems reaching some $250 m annually. Now, with wireless local area networks (LANs) ubiquitous and demand for higher wireless transmission rates using IEEE 802.16 and similar standards growing, new potential applications for photonics in wireless communications are emerging, to generate, modulate and detect signals at higher carrier frequencies (>60 GHz) that can support Gb/s data rate

Assessing written work by determining competence to achieve the module-specific learning outcomes.

This chapter describes lasers and other sources of coherent light that operate in a wide wavelength range. First, the general principles for the generation of coherent continuous-wave and pulsed radiation are treated including the interaction of radiation with matter, the properties of optical resonators and their modes as well as such processes as Q-switching and mode-locking. The general introduction is followed by sections on numerous types of lasers, the emphasis being on todayʼs most important sources of coherent light, in particular on solid-state lasers and several types of gas lasers. An important part of the chapter is devoted to the generation of coherent radiation by nonlinear processes with optical parametric oscillators, difference- and sum-frequency generation, and high-order harmonics. Radiation in the extended ultraviolet (EUV) and x-ray ranges can be generated by free electron lasers (FEL) and advanced x-ray sources. Ultrahigh light intensities up to 1021 W/cm2 open the door to studies of relativistic laser–matter interaction and laser particle acceleration. The chapter closes with a section on laser stabilization