Top 5 Considerations when Choosing Laser Diodes

When purchasing laser diodes for any application, engineers, technicians and procurement specialists generally refer to certain specifications that their system or application requires. When you buy laser diodes, there are certain criteria that ensure the correct laser diode is chosen for your application.

Below we have listed 5 key considerations when choosing laser diodes for an application:

1. Manufacturer

Choosing the correct manufacturer is important. Having a reliable vendor who deals directly with engineers on the latest technology allows access to the most up to date advances in laser diode development.

2. Wavelength

The choice of wavelength depends on the application. For instance, in barcode scanning where a visible red output is required, a 650nm wavelength is often the optimum choice. In other cases, the wavelength would be chosen in relation to how the light interacts with a given medium, such as scattering from smoke particles, absorption by skin tissue, or fluorescence of different particles. Cost may also drive an element of wavelength choice, as well as tight tolerance of specific wavelength.

3. Power output

The application will dictate the power requirement. For instance, patient alignment may require <1mW, however 3D scanning may require >50mW to optimize image contrast. The diode power is generally a key consideration to comply with a certain laser safety classification.

In general it is best practice to choose a device with at least 20% more power than required. This will allow capacity for unanticipated power spikes and also ensures maximum diode lifetime.

4. Pin Configuration

Most devices are generally available in a number of pin configurations connecting the laser diode and photodiode anode/cathode to the case of the device. The choice of pin type is important to determine the housing polarity when mounting the device and whether any electrical insulation is required.

5. Divergence Angles

This is important for optical designers in determining parameters such as circularity, minimum spot size, collimated beam divergence or coupling efficiency into an optical fiber. The divergence angles do vary within any given batch of diodes, so it is important to understand the manufacturer’s typical distribution which may be narrower than the data sheet values. A vendor with close ties to the manufacturer can generally supply extensive distribution data which can help improve manufacturing production yields.

For More Information

With over 20 years’ experience in distributing and working with laser diodes, ProPhotonix work closely with the R&D departments and engineers at all the major laser diode manufacturers – giving us access to the latest in laser diode technology. If you would like to search for a diode yourself try our laser diode selector which provides further information and datasheets for all of our manufacturer’s parts. Alternatively, for support in selecting the best laser diode for your application, contact us.