Abstract: A method of performing spectroscopic measurements provides an optical frequency comb, and directs the comb through or at a sample. The optical frequency comb is generated by gain switching a laser diode constructed from Gallium Nitride and related materials. Various techniques are described for manipulating the comb source to achieve desired benefits for spectroscopy.

Abstract: A device for measuring optical spectra at high speed and with high resolution using tunable optical laser comb sources. In one embodiment there is provided a first tunable comb laser source and a second tunable comb laser source whereby the wavelength of each comb laser source is chosen such that the combination of the two sources provides a continuous spectral coverage over a band in an optical spectrum under a selected wavelength tuning condition. By overlapping the two comb sources in the manner described the deadzone issue is overcome in the most spectrally efficient way possible.

Abstract: A device for measuring optical spectra at high speed and with high resolution using tunable optical laser comb sources. In one embodiment there is provided a first tunable comb laser source and a second tunable comb laser source whereby the wavelength of each comb laser source is chosen such that the combination of the two sources provides a continuous spectral coverage over a band in an optical spectrum under a selected wavelength tuning condition. By overlapping the two comb sources in the manner described the deadzone issue is overcome in the most spectrally efficient way possible.

Abstract: A device for measuring optical spectra at high speed and with high resolution using tunable optical laser comb sources. In one embodiment there is provided a first tunable comb laser source and a second tunable comb laser source whereby the wavelength of each comb laser source is chosen such that the combination of the two sources provides a continuous spectral coverage over a band in an optical spectrum under a selected wavelength tuning condition. By overlapping the two comb sources in the manner described the deadzone issue is overcome in the most spectrally efficient way possible.

Abstract: A method of performing spectroscopic measurements provides an optical frequency comb, and directs the comb through or at a sample. The optical frequency comb is generated by gain switching a laser diode constructed from Gallium Nitride and related materials. Various techniques are described for manipulating the comb source to achieve desired benefits for spectroscopy.

Abstract: In wavelength switching optical networks, the optical data being transmitted may be routed to different end points by switching the operating frequency of the laser. However, the phase noise of the laser source increases following a switching event. This increased phase noise can prevent the successful transmission of phase modulation formats which are sensitive to it. Accordingly, it is generally necessary to wait a short period before transmitting data. However, the period may be as long as the data packet being transmitted (e.g. 3 ?S), which is a limiting factor. The present application obviates this problem by including a radio frequency pilot tone with the data prior to modulation onto the optical carrier.

Abstract: According to the invention there is provided a tunable laser system for use in an optical communication system, said tunable laser system comprising a multi-section laser separated by at least two slots to define a plurality of sections, each section adapted to provide an optical gain. Each section comprises a separate control means to provide an adjustable optical gain in each section. The tunable laser system and method of the present invention provides a wide tuning range, narrow linewidth and fast switching times.

Abstract: A contract management system accessible by a plurality of users is disclosed, which has a data store containing user data and project data, said user data including, for each user, a user-type identifier indicating whether said user is a contract manager, client, clerical support or a consultant; project control means accessible by a contract manager to create project data for a project, said project data including an indication of user data for a consultant engaged under contract for the project, and deliverables data corresponding to deliverables to be provided under said contract, and financial data for said project; said project control means being accessible by the consultant to submit financial data for a project which the consultant is engaged on, and to submit variations to said financial data for a said project; said project control means being further accessible by said contract manager for a project to authorise said variatons to the financial data for that project and to authorise payment to the c