Distributed feedback, DFB, lasers are a major source for long haul optical fibre based
telecommunication systems. They rely on ultrahigh precision gratings to reduce mode
competition within the laser cavity, thereby making single frequency operation possible.
Techniques applied to DFB grating manufacture tend to be either holographic, or a direct
serial write process using slow and expensive electron beam lithographic machines. An
entirely new approach is proposed which compliments the accuracy of the electron beam
systems with the high throughput and relatively low cost of a conventional contact mask
regime. The new process relies on a group of materials which are able to retain an
embossed relief upon curing with ultraviolet radiation. The main manufacturing stages of
this new technique are presented including details of the embossing tool fabrication using
reactive ion etching, and characterisation of material properties. It is proposed that the
technique, whilst intended for DFB manufacture, could find applications in many other
areas, for instance as a route to low cost replication of photomasks. In addition a new
grating assessment technique, based on normal reflectance measurements, has been
developed. The technique has been used to investigate hitherto unmeasured effects in
electron beam lithography on a variety of substrate materials before and after
semiconductor overgrowth. Details of a theoretical exercise which agrees closely with
experimental results are included. The technique is non-destructive and should be of
interest to all areas of microlithography and holographic imaging where it is important to
have control over a wide range of process stages or where the feature size rules out the
use of conventional optical microscopes.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.