New possibilities for environmental and medical sensing

  

The company says its AQ6377 device is the world’s first OSA that allows side mode analysis of MWIR lasers.

Lasers are increasingly being used for environmental sensing applications to detect gases such as CO2, N2O and NO. Different gases have different wavelength absorption lines, however, the side modes of the laser reduce the laser’s capability to distinguish between the various gases.

In the mid infrared range (3.5 to 5µm) the AQ6377 is the only OSA capable of analysing the wavelength spectrum of lasers, including their side modes, with high accuracy.

Lasers are also increasingly being used for medical spectroscopy diagnostics, particularly Quantum Cascade Lasers (QCLs). These operate using a pulsed technique, across a very wide wavelength range. The Yokogawa AQ6377 offers the capability to perform stable measurements in this wide wavelength range. It can also evaluate pulsed QCL signals with low repetition rates, which has hitherto been difficult to achieve.

Key features of the AQ6377, include a wavelength resolution of 0.2 nm, a wavelength accuracy of ±0.5 nm, a high dynamic range of 50 dB, and a level sensitivity down to -60 dBm. The wide dynamic range and high sensitivity have been achieved by reducing the influence of stray-light in the monochromator.

The built-in calibration light source takes advantage of the natural absorption properties of acetylene gas to deliver a wavelength calibration signal which is accurate to 0.6 picometres. This source is also used in conjunction with the automatic optical alignment capability to compensate for any deviation in the optical axis caused by vibrations and shock suffered in transit, and those due to temperature changes. Using those features, the AQ6377 can maintain its high optical performance on site.

Terry Marrinan, VP Sales & Marketing Yokogawa Europe and South-East Asia, commented, “With the global attention to air quality and the effects of greenhouse gases, we take pride in our ability to help improve the accuracy of their measurements. By creating the AQ6377 high performance OSA, we are responding to the needs of customers developing solutions for optical gas sensing as well as surgical equipment who require measurement equipment of a maximum performance that is also easy-to-use and maintain.”