Laser Beam Couplers series 60SMF

with fine threaded adjustment screws - for coupling into single-mode and polarization-maintaining fiber cables

60SMF-1-4
60SMF-1-4
60SMF-1-4
60SMF-1-4
60SMF-1-4
Representative product images. Individual product images are found on the individual product pages.

Features

The fiber couplers series 60SMF with fine threaded adjustment screws are an improved, advanced version of the fiber couplers 60SMS. They are high precision fiber couplers optimized for high coupling efficiency, high pointing stability and long-term stability and provide efficient coupling of ­collimated laser radiation into ­single-mode and PM fiber cables.
  • All appreciated benefits of the well-established 60SMS laser beam coupler including its very high pointing stability and as well as the proven long-term stability.
  • Ceramic bearings and adjustment screws with fine thread to ensure an even more precise and easy adjustment.

  • For single-mode or PM fiber cables
  • System mount Ø 19.5 mm
  • Integrated TILT and focusing adjustment
  • Focal lengths up to 18 mm
  • Choice of aspheres, monochromats, achromats and apochromats
  • Various AR coatings for UV - IR
  • Choice of fiber receptacles: FC PC or FC APC (standard), many others available
  • Eco brass ® (standard) or amagnetic titanium
  • With integrated TILT adjustment

Description

The fiber couplers series 60SMF with fine threaded adjustment screws are an improved, advanced version of the fiber couplers series 60SMS.They are designed for compact and long-term stable coupling of single-mode laser radiation into a single-mode or polarization-maintaining fiber. For multimode applications please use the series 60FC-A19.5 fiber couplers.

An optics for each application
A large variety of coupling optics allows that the optimum focal length and the best lens type for a single wavelength (asphere, monochromat) or a wavelength range (achromat or apochromat) can be selected for each application. All lenses are AR-coated. For an ideal Gaussian beam and standard fibers you can reach coupling efficiencies up to 80%.

High long-term stability
It‘s compact size as well as the high-resolution alignment mechanisms allow for a straight-forward, intuitive coupling procedure. The result is a fiber coupling with high thermal stability, pointing stability, that is vibration and shock-insensitive. Long-term stability tests (see figure on the right) have shown a power stability better than 3% for a temperature range of 15-35°C.

6 Degrees of freedom*
In order to achieve optimum coupling efficiency the fiber coupler needs to provide certain degrees of freedom. You need to adjust

  • the angle between laser beam and lens/fiber end-face
  • the z-position of the lens
  • adjust the polarization axis of the fiber to that of the laser source
  • center the lens with respect to the laser beam

The fiber coupler provides all degrees of freedom necessary. It has a TILT adjustment, an independent focus adjustment, can be rotated 360°, and allows for lateral adjustment* using e.g. the adapter 60A19.5-F.
The TILT adjustment is used to maximize the lateral overlap between the mode field of the fiber and the focussed laser spot using 3 adjustment screws. It has ceramic bearings and the adjustment screws have a super-fine thread to ensure an even more precise and easy adjustment. 3 locking screws are used for fine-adjustment and to lock the position for an optimum mechanical stability.
Independent to the TILT adjustment, the distance between fiber end-face and coupling optics is adjusted by means of an eccentric key. The final focus setting is locked by means of two radially arranged clamping screws. Since the focus adjustment is independent, the z-position of the mode field diameter can be placed much more precisely.
The polarization alignment of the fiber to the polarization axis of the laser source is performed by rotating the laser beam coupler. The separation of the fiber coupler and the adapter necessary for centering is essential to allow for a full 360° freedom of rotation. The coupler has a tight-fit cylinder that can be placed into a Ø 19.5 mm receptacle of a corresponding adapter.
The beam can be centered with respect to the aperture of the coupling optics using e.g. the adapter 60A19.5-F

Optimum lens performance
The angled polish of connectors of type APC causes the beam to exit in an angle and not parallel to the optical axis of the fiber. This is corrected by the pre-angled mechanical coupling axis of the coupler that compensates the beam deflection and you can use the lens centrically. This minimizes aberrations simply resulting from a non-ideal beam path through the lens.

Connector Type options
The fiber coupler can be equipped with receptacles of type FC PC, FC APC, ST or LSA (compatible with fiber connectors type DIN, AVIO and AVIM). F-SMA type receptacles are available for 0° and 5° or 8°-polish e.g. for SMA-905 High Power connectors. In case of FC or LSA with a spring loaded ferrule the fiber coupler has an additional grub screw to increase pointing stability.

Material Options
The fiber couplers are available in eco brass ® (standard) or in amagnetic titanium. In case of titanium, the relative permeability is near 1 (µr=1.00005) making it almost transparent to magnetic fields. The linear coefficient of thermal expansion is close to that of the optics so that a thermal stability over a larger temperature range can be expected.

FAQ

  • Adjustment
    • How much can I change the focus setting?
      For couplers and collimators with a focal length < 12 mm you can change the focus setting ± 0.5 mm. For couplers and collimators with a focal length ≥ 12 mm you can change the focus setting ± 1.0 mm.
    • I am unsure how to correctly adjust my coupler/collimator. Where do I find details about the adjustment procedure?
      Please refer to the manual in the Downloads section for a detailed adjustment procedure.
  • Fiber Receptacle
    • FC PC and FC APC
      • How do I attach a fiber cable?

        1. To prevent damage to the sensitive fiber end-face, always insert the fiber connector`s ferrule at an angle, with the connector key properly aligned to the receptacle notch.
        2. When the ferrule tip is safely located in the inner cylinder of the receptacle, align the connector to the receptacle axis and carefully introduce the connector into the fiber coupler.
        3. Then, orient the connector key in a way that it is pressed gently onto the right-hand side of the receptacle notch ("right-hand orientation rule").
        4. Gently screw on the connector cap nut onto the receptacle until it is finger-tight.
        5. Gently tighten the fiber grub screw to reduce the free play of the ferrule in the receptacle.

      • What is the "right-hand orientation rule"?

        When the ferrule tip is safely located in the inner cylinder of the receptacle, align the connector to the receptacle axis and carefully introduce the connector into the fiber coupler. 

        Then, orient the connector key in a way that it is pressed gently onto the right-hand side of the receptacle notch.

        The tightened grub screw and the "right-hand orientation rule" for the connector, ensure a high reproducibility in mode field position and angle, which is especially important for attaching and reattaching polarization-maintaining fibers reproducibly.

      • Can I attach a narrow key fiber cable to a fiber coupler with a wide key receptacle?

        Yes you can- without any problem. Simply adhere to the "right-hand orientation rule".

        Generally, with any FC PC or FC APC type connector there is a freeplay when inserting the fiber into the fiber coupler. The free play in between the connector ferrule and receptacle is only a few microns, but necessary for inserting the ferrule without force. There is a difference between the receptable and key width for wide key (2.14 mm) and narrow key (2.0 mm) fibers. If you follow th so-called "right-hand orientation rule" you can reproducibly attach and reattach even PM fibers  with narrow key receptacle to fiber couplers with wide key receptacle without difficulty.

        "Right-hand orientation rule":

        When the ferrule tip is safely located in the inner cylinder of the receptacle, align the connector to the receptacle axis and carefully introduce the connector into the fiber coupler. Then, orient the connector key in a way that it is pressed gently onto the right-hand side of the receptacle notch.The tightened grub screw and the "right-hand orientation rule" for the connector, ensure a high reproducibility in mode field position and angle, which is especially important for attaching and reattaching polarization-maintaining fibers reproducibly.


Downloads

Adjustment_60SMF.pdf (Manual)

This downloads section only includes general downloads for the complete series.
Please access the individual product pages (using the product configurator, the product list, order options or the search button if you have a complete order code). Here you will find specific downloads including technical drawings or stepfiles.

Accessories