Adjustable focus source couplers are ideal for situations where optical coupling efficiency is critical, such as in high power applications. A special connector allows the spacing between the fiber and lens to be precisely controlled without rotating the fiber. This is ideal in polarization maintaining applications, as the polarization axis does not change. The adjustments allow one to compensate for any change in wavelength or beam wave location, thus further optimizing the coupling efficiency. The minimized coupling efficiency lead to minimized heating of the fiber, especially important with high power. Adjustable focus couplers are available with a variety of lens types and fiber types. Internal surfaces are angle polished and/or AR coated to minimize backreflection. Typical backreflection levels are -40dB. -60dB is available for certain options. OZ Optics also sells fiber patchcords with adjustable FC/PC connectors only. Please see our online catalog at https://shop.ozoptics.com for standard parts and specifications. Contact OZ Optics for further assistance.