Optical parametric oscillator (OPO) lasers test optical fibers and components to characterize the spectral response of optical components, providing a competitive advantage in the optics industry.
OPO lasers have been used for many years in advanced test and measurement applications such as mass spectrometry, photoacoustic imaging, and spectroscopy. These “tunable” pulsed lasers now facilitate a variety of tests at different wavelengths to evaluate and quantify the performance of optical components such as fiber optic strands, filters, lenses, and coated mirrors. It is used to.
By design, most optical components reflect, filter, or transmit specific wavelengths or ranges of wavelengths. Therefore, it is important to perform testing of component materials and coatings to ensure that the product performs as expected. The more accurate these tests are, the better the quality of the product, which can give manufacturers a competitive advantage.
Because test conditions must reproduce or simulate real-world operating environments, lasers can be used to provide narrow wavelength bands, pulse widths (if applicable), and power levels to determine the spectral response of optical components. Masu.
These tests provide optical component manufacturers with important information related to factors such as absorption, scattering, and other optical properties. Damage testing has become essential to determine whether a particular optical material can be damaged at different wavelengths. Also, certain wavelengths can damage the coating and cause performance issues.
With such a range of tests, it would be advantageous to be able to tune the laser to the required wavelength. This increases flexibility and reduces complexity, allowing manufacturers to ensure that their optical products perform as expected.
pulse based pulse
Using pulse-based lasers offers significant advantages. Continuous wavelength lasers are an inexpensive solution for testing optical materials, but they do not offer a wide range of high-resolution wavelengths and are limited in the peak power they can generate.
Pulse-based lasers produce high-intensity bursts of light that can be used to determine whether the transmission properties of optical materials or coatings are affected. Optical component manufacturers are using this technology to determine whether high-intensity light causes damage such as nonlinear effects (creating unwanted wavelengths), solarization, and photobleaching across the wavelength spectrum, including into the deep ultraviolet (UV). may need to be tested. Continuous wave lasers are not powerful enough for this level of damage testing.
If a single-wavelength pulse-based laser is required, the relatively inexpensive and easy-to-use Nd:YAG (neodymium-doped yttrium aluminum garnet) laser is an ideal choice. The 1064 nm laser can also be modified to operate at other harmonic frequencies (213, 266, 355, and 532 nm) using additional hardware. This provides five defined wavelengths for testing, but each change increases cost.
There is a gap between the wavelengths, and the change from 1064 nm to 532 nm is noticeable. Each of these harmonics increases cost. Optical component manufacturers want to know how their products perform at wavelengths between these harmonics.
A more versatile, high-resolution option is an OPO laser that can be tuned to specific wavelengths across a broad spectrum. In this approach, the OPO converts the fundamental wavelength of pulsed mode Nd:YAG to a selected frequency. Manufacturers such as Opotek (Carlsbad, California) have developed a series of his OPO technologies that can easily produce many wavelengths from deep ultraviolet to mid-infrared.
For example, an OPO laser can be tuned to wavelength resolution by simply punching in a number (for example, 410, 410.1, or 410.2 nanometers). Some tests require high resolution wavelengths, which may not be achievable with broadband light sources.
Test the limits of optical components
Many optical components are sensitive to specific wavelengths, and destructive damage testing determines the limits to which the material can withstand. Laser-induced damage threshold testing is one example.
Certain wavelengths can cause photochemical reactions within optical materials, changing their molecular structure and chemical composition, reducing their effectiveness. Some materials can absorb certain wavelengths of light, which can cause localized heating and potential thermal damage. When light intensity exceeds a material's damage threshold, melting, evaporation, cracking, or other physical damage can occur.
Optical fibers and components often have protective coatings, which also make them susceptible to damage from certain wavelengths. One of the most common applications is optical fibers, where prolonged exposure to high-intensity laser light can cause various forms of damage. To test a strand of optical fiber, a laser beam is sent from one end to the other to evaluate the fiber's performance and properties.
For example, to determine peak power, pulse-based OPO lasers can deliver concentrated bursts of energy with short durations measured in nanoseconds. Peak power is calculated by dividing the energy of a single pulse by the pulse duration, so OPO lasers can deliver megawatts of energy compared to milliwatts of continuous wave lasers.
Given the different testing possibilities at different wavelengths, optical component manufacturers would be wise to consider the benefits of pulsed-based OPO lasers. The flexibility and resolution provided make it ideal for measuring the absorption, transmission, and reflection properties of materials and coatings, as well as for damage testing. By doing so, manufacturers can ensure that their optical products perform as expected, giving them a competitive advantage in the optical industry.
