Power stabilization of the wavelength-variable lasers

Customer’s situation

When adjusting the assembly of the wavelength-variable lasers, there are cases in which laser output is not obtained sufficiently, and the production department has demanded early improvement. As a result of the investigation, they found that the sufficient output was obtained when the diffraction grating was replaced with the other one. Therefore, they thought individual variation of the diffraction gratings have an effect to the output.
To solve this problem, they would have wanted to identify the cause and apply the improvement into to the specification of the diffraction grating.

Advantages of Shimadzu products

Note: What affects laser output?
"Diffraction efficiency" and “Diffraction wavefront accuracy" are possible specifications of the gratings that affect the laser output.
The diffraction efficiency is a value that expresses the extent to which energy can be obtained from diffracted light with respect to the energy of the incident light.
Also, the diffraction wavefront accuracy affects the characteristic of diffracted light.

★Advantage1: Stable and high diffraction efficiency
Shimadzu is able to offer the diffraction gratings with extremely high relative diffraction efficiency for S-polarized near infrared light.
Shimadzu have its own diffraction efficiency measuring equipment and can provide diffraction gratings that guarantee efficiency. 

★Advantage2: Excellent diffraction wavefront accuracy
The diffraction wavefront accuracy is mainly determined by the "surface accuracy of the substrate" and the "accuracy of the grating’s groove". Shimadzu's excellent substrate polishing, grooving and replicating technologies enable stable production of gratings with excellent diffraction wavefront accuracy.
Also, accuracy can be guaranteed by Fizeau laser interferometry *.
*The guaranteed diffraction wavefront accuracy is compatible with λ, λ/2, λ/4, etc., depending on the product and application.

Benefits by using Shimadzu products

They were able to identify the specifications of the grating that solve the insufficient output and apply the improvement into the specifications of the diffraction gratings.
As a result, output insufficiency of the tunable laser no longer happened.

Customer’s feedback

I have never thought diffraction wavefront accuracy affect the output so much.
Shimadzu diffraction gratings are also stable in diffraction wavefront accuracy in addition to its diffraction efficiency, so we can install them with no worry.
Our production department also appreciated it!

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