In the “real world”, Photonics is somewhat invisible to those who rely upon it worldwide. We would like students to connect their everyday experiences of communications with the underlying ideas in Photonics. To do this, we have developed the Photonics Simulator to illustrate to high school students how text or information is coded into binary optical signals which are relayed through photonic communications networks from sender to receiver. Using our simulator, students construct a virtual network, and then test it by sending messages. The messages are coded using ASCII binary code as digital signals in data packets with address headers, which need to be switched, combined, amplified, or delayed to get to their designated address. The students must manage their power budget, correctly target each message address, and avoid collisions of data packets to send their messages uncorrupted and error-free. We tested an early version of the simulator with five Year 9 and 10 classes. The students provided many constructive comments and their feedback was used to improve the graphical interface of the simulator. We subsequently tested the simulator with 80 Year 9 students in short workshops. Overall we had a very positive response - it was more fun than a normal class, and interactivity helped students retain information. Students enjoy the visual aspects– they see how messages are delivered, and learn the function of each network component by experiment. Tests of the simulator at the Macquarie Siemens Science Experience were also encouraging, with one student even sneaking back to class to complete his challenges!
By identifying appropriate quasi-phase-matching (QPM) conditions in z-cut congruent lithium niobate, we demonstrate
simultaneous QPM of type-I (ooe) and higher order type-0 (eee) second-harmonic-generation, which share a common
second harmonic wave. We demonstrate this experimentally at 1064nm, and show that cascading between these
processes occurs. The cascading can result in energy exchange between the cross-polarized fundamentals, indicative of
an equivalent 3rd order process. The nonlinear phase shifts and transfer functions resulting from this cascading are
Fabrication of quasi-phase-matching (QPM) gratings suitable for cascading of two second-order parametric nonlinear
processes in a single lithium niobate crystal is being undertaken using a new technique - electric field poling assisted by
laser micro-machined topographical electrodes. To date, single period poled gratings with 45.75, and 45.8 &mgr;m periods
have been fabricated in order to demonstrate second harmonic generation of 1064nm laser light with 1st order type-I and
7th order type-0 QPM simultaneously. The two frequency doubling processes share a common Z polarized second-harmonic
wave which allows exchange of energy between the two orthogonally polarized fundamental waves and
several second order cascading interactions can be realized. The use of the higher QPM orders (3rd, 5th or 7th) for the
type-0 second harmonic generation process leads to comparable efficiencies of the two processes, as the respective
nonlinear coefficients are dzzz ~27 pm/V and dyyz ~ 4.7 pm/V in lithium niobate crystals. Possible applications include;
polarization switching, parametric amplification and polarization mode dispersion monitoring, and polarization
insensitive second harmonic generation.
Fabrication processes such as laser micromachining and laser based photolithography are well established within the automotive, electronics and aeronautic industries, however, except in a handful of cases, laser based micro-processing is infrequently used in the fabrication of photonic devices. In this paper novel laser assisted methods for rapid prototyping of photonic devices such as periodically poled lithium niobate and 2-D photonic crystal structures are reviewed.