Med-Tech Sensors

Develop more laser applications with wide wavelength OSAs

by Yokogawa Test&Measurement February 23, 2023

Lasers are so common today that it’s hard to believe there was a time when they didn’t exist – from enabling optical communication networks, to detecting air pollution and being used in surgery, lasers are everywhere.

With so many uses already, and many others being found all the time, manufacturers are obviously keen to have a capable and convenient way to test and evaluate new optical products.

This means developers are keen to find a vendor that can offer a wide range of wavelength measurements in a single family of optical spectrum analyzers – no-one wants to have to buy widely different devices from different sellers just to measure an extra wavelength range. Commonality is key to ease of use and speed of testing, allowing direct comparisons of products under test and ensuring time to market is minimized.

To meet these requirements, Yokogawa has launched two new optical spectrum analyzers (OSAs) designed to meet testing needs in both optical product development and manufacturing.

The Yokogawa AQ6375E and AQ6376E are the only grating based OSAs covering SWIR (Short-Wavelength InfraRed) over 2 μm and MWIR (Mid-Wavelength InfraRed) over 3 μm with world class optical performance.

The new OSAs are offered in four versions, each covering a specific wavelength range.

The AQ6375E Standard has a wavelength range of 1200-2400nm; the AQ6375E Extended Wavelength version has a wavelength range of 1000-2500nm; the AQ6375E Limited version has a wavelength range of 1200-2400nm (with reduced wavelength resolution); and the AQ6376E Standard has a wavelength range of 1500-3400nm.

This extensive choice of wavelengths gives developers and manufacturers greater flexibility in the range of wavelengths they can measure, all in one highly accurate and very useable family of OSAs.

This flexibility allows developers to use the OSAs in a wide range of applications. These include environmental measurement and gas sensing, where the OSAs will find use in the measurement of gas absorption spectra and the characterization of light sources used in Laser Absorption Spectroscopy.

Other possible applications are in medical care and biotechnology products and industrial laser development. The AQ637xE will extend the number of optical products that can be analyzed, both in development applications and in production.

High accuracy of course is paramount. One source of error for OSAs is deviations in the optical axis caused by vibrations and impacts.  Wavelengths can also deviate due to changes in ambient temperature.

To compensate for these possible errors, the AQ637xE has a built-in calibration system, which uses an onboard light source for optical alignment and wavelength calibration.

Other errors that can plague OSAs are related to the SWIR and MWIR region. Here, there are wavelengths where light shows strong absorptions due to water vapor and carbon dioxide, which can both disturb the spectral measurement.

To combat this, the AQ637xE continuously supplies pure purge gas such as nitrogen to the monochromator, reducing the influence of light absorptions on the measurement.

Ease of use is key to rapid measurements. The AQ637xE’s offers a high-resolution, responsive 10.4-inch multi-touch capacitive LCD touchscreen, which makes operating the device simple and more intuitive – users can change measurement conditions, perform analysis and change the optical spectrum view as simply as operating a tablet device.

Once you have the results, analysis is the next step – built-in analysis functions can characterize optical spectrum from a variety of optical systems and devices, such as WDM system, DFB-LD, EDFA, and filters.

With a family of OSAs offering a large choice of wavelengths, together with high accuracy, manufacturers are ready to develop and produce a wide range of new optical devices, for many applications.