What Is a Wavelength Meter?
A wavelength meter measures light’s wavelength, offering higher sensitivity than optical spectrum analyzers due to its narrow dynamic measurement range. While optical spectrum analyzers provide broader functionality, wavelength meters focus solely on measuring wavelengths, making them more affordable. The measurement reflects the wavelength in a vacuum, with a minor discrepancy from air measurements due to the air’s refractive index.
Uses of Wavelength Meters
Wavelength meters are vital for tasks requiring precise wavelength accuracy, such as characterizing optical components, measuring narrow-bandwidth light sources like lasers and LEDs, and evaluating light in optical fiber communications. They are especially common in measuring light between 1,000 and 1,800 nm, critical for optical fiber communications.
Principle of Wavelength Meters
Wavelength meters utilize physical light interference, employing Fizeau or Michelson interferometers to measure wavelength. These interferometers create interference fringes from light beams, unique to each wavelength and the optical path difference. The wavelength is calculated based on the known optical path difference and the interference pattern observed.
Other Information on Wavelength Meters
1. Wavelength Meter and Optical Fiber Communications
Essential for optical fiber communications, wavelength meters measure the 1,500 nm band, the most efficient for minimizing light loss. As the demand for bandwidth increases, wavelength meters now often measure multiple wavelengths simultaneously, with advanced models handling up to 1,024 wavelengths to support wavelength multiplexing technologies.
2. Applications Beyond Optical Fiber Communications
Wavelength meters also serve in semiconductor laser evaluation for optical communications, with models that rapidly assess single wavelengths on production lines. Additionally, they support measurements in bands below 1,000 nm for optical fiber amplifiers and cater to applications like optical coherence tomography in ophthalmology and fluorescence observation in biotechnology, with models covering 300 nm to 1,200 nm.
3. Compatibility With CW and Pulsed Light Sources
Some wavelength meters accommodate both continuous wave (CW) and high-speed pulsed light sources, which are crucial for various laser applications. It’s important to select a model based on its compatibility with the intended light source.