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Definition: the process of developing a laser device
This article discusses the process of developing laser devices. It does not focus on any particular technical details, but rather addresses the more general issue of arranging an efficient development process.
Many aspects apply in very similar form to other types of photonic devices, such as parametric oscillators.
In Short
Due to the complexity of laser devices and their physical basis, the effectiveness, speed and cost of laser development projects are strongly dependent on a well structured process. A crucial point is solid laser design work at the beginning, not only as a reaction to already severe problems. The laser design is then not the result of a complicated development process, but rather its basis, as well as a valuable input for the next project.
A Systematic Procedure for Laser Development
Non-systematic approaches to laser development can fail for many reasons. A systematic procedure as described in the following can be much more efficient concerning time and resources:
- The first step is a careful assessment of what exactly is required. It is essential to realize all requirements at this stage, because it can be much more costly to introduce additional properties of the laser at a later stage.
- The second step is to check whether the envisaged technology is overall appropriate, and perhaps to compare the chosen approach with competing options. This step is essential, because mistakes made at this stage would affect the whole development process. An experienced laser engineer is therefore strictly required.
- The next step is to work out a detailed laser design. This process involves quantitative checks of various issues before any laboratory work is started. For example, if a passively mode-locked bulk laser is developed, this process can include calculations (not necessarily detailed modeling) concerning the pump intensity and laser gain (at different wavelengths), the threshold pump power, the balance of chromatic dispersion and nonlinearity in the resonator, the expected alignment sensitivity, the required modulation depth of the SESAM, the overall operation point of the SESAM concerning degree of saturation, the strength of pulse shaping, etc. Various problems can be identified, enforcing design changes at this early stage and leading to a design which is free of a number of foreseeable problems. The “deliverable” of this design phase is a clearly written design report, containing not only all the parameters of the suggested prototype but also a clear description of the reasoning behind the design and possibly the likely limitations, some warnings, the list of required parts, etc.
- Only after this stage are the required parts ordered and the prototype is built, following the detailed prescriptions in the laser design. The prototype may exhibit minor problems which can be fixed within a short time. Nevertheless, this phase of the development (largely taking place in the laboratory) normally consumes more time than the preparatory steps.
- Further steps often have to be taken to turn the prototype design into an industrial design which is suitable for efficient production, sufficiently robust for practical application, and overall convenient for the customers.
- Other than the design document, the user manual can be written after all the prototype testing and refinement. Here, it is an advantage already to have all the practical experience with the device.
The advantages of this structured approach are manifold:
- Most importantly, the costly and time-consuming laboratory work can be done in the most efficient way. Compared with a trial-and-error approach in the laboratory, it is easier to identify problems, their causes and suitable solutions on paper and/or with a computer, because this process is not limited by, e.g., available diagnostics, access to inner parts of the device, or available alternative optical components.
- As another consequence, the laser product can enter the market sooner, thus generating revenue at an earlier time and positioning the company in the market.
- The well-documented laser design helps the development team to learn more about the technical details, and is a very useful input for any further development – even if that is carried out by other personnel.
- An often comparatively minor advantage of a well-planned development process is that fewer parts are ordered which are not used in the end.
A frequent mistake is to consider the laser design document as a side product of the development process, rather than as its basis. This easily leads to inefficient iterative steps in the laboratory, which can consume much more time and resources than the process of working out a detailed design in an earlier phase.
See also: laser design, Spotlight article 2006-07-05, Spotlight article 2006-12-09, Spotlight article 2007-03-16, Spotlight article 2007-11-26, Spotlight article 2008-02-14, Spotlight article 2009-06-29, Spotlight article 2010-07-12
This encyclopedia is authored by Dr. Rüdiger Paschotta, the founder and executive of RP Photonics Consulting GmbH. Contact this distinguished expert in laser technology, nonlinear optics and fiber optics, and find out how his technical consulting services (e.g. product designs, problem solving, independent evaluations, or staff training) could become very valuable for your business!
