Introduction:
Diode lasers are cost effective opto-electronic devices which cover a wide variety of applications. For most applications in the field of measuring and sensing, there is an improvement of the spectral properties needed. Technically, this is realized by using external cavities. For a proper coupling of the external cavity to the diode laser, an anti-reflection coating of the front facet of the diode laser is required.  

Innovation:
Sacher Lasertechnik was the first business to introduce anti-reflection coated diodes into the world market as early as 1992. First successful anti-reflection coatings were realized as early as 1987 at Marburg University. Dr. Joachim Sacher was one of the first scientists who realized the potential of this technology.

Benefit of AR-coated diode lasers, Laser Performance:
Our anti-reflection coated diode lasers give the laser system the performance of a turnkey system. These is no longer the need for a long term search of the current and temperature values of the operating point. Our customers benefit from our experience of more than 15000 installed anti-reflection coated diode lasers in experimental and industrial laser systems. Make sure to include the Original Anti-Reflection Coating within your laser system. 

Benefit of AR-coated diode lasers, Wavelength Tuning:
Using our anti-reflection coated diode lasers within an external cavity laser system increases the total tuning range of diode lasers up to a factor of 2 in comparison with standard diode lasers. Spectral regimes beside standard wavelengths are easily accessible. 

Benefit of AR-coated diode lasers, Large Mode-hop free Tuning Range:
Employing standard diode lasers within an external cavity laser system causes a coupled cavity system. This results in the coherence collapse (Sacher et al., Phys. Rev. A45, 1893 (1992)) and only very small tuning ranges of a few GHz can be reached.  The performance of our anti-reflection coated diode lasers enables our laser systems for large mode-hop free spectral tuning. Our external cavity Littman laser system is especially designed for achieving high mode-hop free tuning range.

Specifications:
R<=5E-4, typical values R<=5E-5. For our standard coatings, we specify the minimum of the reflectivity to be below 5E-4. Typical values are R<=5E-5. These excellent values are a result of more than 10 years of experience in the manufacturing of anti-reflections coatings (US Patent 6,297,066). 

Measuring the Reflectivity of diode lasers:
A direct measurement of the reflectivity of diode lasers is barely possible due to the small size of the laser chip. Therefore, we use an indirect method of determining the reflectivity by the method of Kaminov et al., IEEE J. Quantum Electron., QE-19, 493 (1983). An example of applying this method to the newly released GaN laser diodes is given by Hildebrandt et al., published in Applied Optics, April 2003. 

Effect of AR-coatings on diode lasers:
Anti-reflection coating causes a significant change of the physical properties of diode lasers. The most obvious effect is the change of threshold current and of spectral properties. 

Quality Management:
Each anti-reflection coated diode laser will be delivered with an individual datasheet. This datasheet provides information on the change of the PI-curve as well as on the spectral performance of the device. 

Lifetime Data:
We have performed lifetime testing on a 25 unit batch of our anti-reflection coated diode lasers employing the accelerated aging method. As a result, we have found the mean time to failure (MTF) not to be affected by anti-reflection coatings as long as the diodes are driven under reasonable conditions. Please check the links for details. 

Manufacturing Capabilities: 
Sacher Lasertechnik operates a full technology line for the assembly and the antireflection coating of diode lasers. 

Laser Bar Coating:
Sacher Lasertechnik has developed a unique method of performing anti-reflection coatings for laser bars, c/f US Patent 6,297,066.