Fiber Collimator series 60FC

for collimating radiation exiting an optical fiber or as an incoupler

Fiber collimator 60FC-4
Fiber collimator 60FC-4
Fiber collimator 60FC-4
Fiber collimator 60FC-4
Fiber collimator 60FC-4
Representative product images. Individual product images are found on the individual product pages.

Features

The fiber collimator is designed for collimating radiation exiting from an optical fiber cable or used in reverse as a fiber coupler (fiber port) for coupling a beam into an optical fiber cable.
  • Focal lengths up to 20 mm
  • Choice of aspheres, monochromats, achromats and apochromats
  • Various AR coatings for UV - IR
  • Choice of fiber receptacles: FC PC or FC APC (standard), ST, LSA or mini AVIM®
  • Compact Ø 12 mm housing
  • Front connector accepts attachment optics
  • Nickel silver or amagnetic titanium


Description

The fiber collimators series 60FC are designed for collimating radiation exiting optical fiber cables with high pointing stability. They can also be used in reverse-mode as fiber incouplers. They are suitable for single-mode and polarization-maintaining fiber cables leading to collimated beams with a Gaussian intensity profile. Please note that for multimode collimation the intensity profile is not Gaussian and depends on specific fiber and radiation properties. 

An optics for each application
A large variety of collimating 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%.

Adjustment of focus
The distance between fiber end-face and collimating optics is adjusted by means of an eccentric key. The lens does not rotate when adjusting the focus. The final focus setting is locked by means of two radially arranged clamping screws. Additionally attachment optics can be mounted to the front of the collimator. 

Optimum lens performance 
The angled polish of connectors of type APC is considered by a pre-angled mechanical coupling axis 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 
The fiber collimator can be equipped with FC PC (wide key*), FC APC (wide key*), ST, LSA (compatible with fiber connectors type DIN, AVIO and AVIM) or mini AVIM® (compatible with mini AVIM® and midi AVIM®) receptacles. SMA-905 (F-SMA) type receptacles are available for 0°-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.*Even though the fiber collimator has a wide key receptacle it still can be used with both narrow key and wide key fibers. More information can be found here.

Material 
The fiber collimators are available in nickel silver (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.

Mounting
The collimator can be placed into a standard mirror mount using the corresponding adapters.

Technotes

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.
    • What is the difference between the eccentric keys type 60EX-4 and 60EX-5?

      Both eccentric keys are used for the fiber collimators series 60FC and the laser beam couplers series 60SMF/60SMS.The difference between the two eccentric keys is their stroke:

      The eccentric key type 60EX-5 has a larger stroke compared to the key type 60EX-4. The 60EX-5 is used for couplers with focal length ≥ 12 mm. The 60EX-4 is used for focal lenghts < 12 mm.

      In some (very, very rare) cases it might be necessary to use the eccentric key type 60EX-5 even for couplers with focal lengths shorter than 12 mm:

      - When the coupler is used with a fiber connector that has an end cap,

      - the coupler is collimated for an extremely long wavelength,

      - the coupler is collimated for an extremely short wavelength,

      - or the coupler is focussed to a finite distance in order to generate a small spot .


    • I do not have a collimating telescope to collimate. Can you give me practical advice?
      Of coarse, a collimating telescope is the best way to collimate. But there are other methods depending on the type of fiber (single-mode and PM vs. multimode) you can use. Please refer to our practical collimating tips here.
    • My collimator is shipped "prealigned". What does this mean?
      Schäfter+ Kirchhoff ships all collimators prealigned and collimated for either a specific wavelength defined by the customer or a typical wavelength. The collimation is performed using professional collimating telescopes.

      Please note: The fibers used in the standard adjustment procedure are all equipped with an end cap when aligning for wavelengths ≤ 520 nm. The adjustment wavelength is given on the label for each collimator/coupler. If a fiber with end cap was used it is marked by "EC".

    • Are you using the optimum groove for adjusting the focus setting with the eccentric key?
      The distance lens to fiber end face is changed by means of an eccentric key. This key has a pin. The lens tube has one (or more) circumferential groove(s). The lens tube is shiftet axially by rotating the eccentric. 

      In order to cover the entire adjustment range, it might be necessary to switch from one to the next circumferential groove. 

      Sometimes it is easier to do a coarse alignment by shifting the rear part manually (instead of using the eccentric key). Then, the right groove for a proper fine adjustment with the eccentric will appear in the aperture of the fiber collimator for the eccentric and you can finish the fine adjustment using the eccentric key.

    • 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.


  • Fiber Collimators with receptacle type SMA
    • Why do we not offer fiber couplers without TILT alignment and a receptacle type F-SMA with an angled polish?

      The fiber connectors of type SMA do not have a spring-loaded ferrule (such as FC type connectors do).

      The receptacles do not have a limit stop.
      Since the length of the ferrule is not defined precisely, the emitting point in the fiber coupler is not properly defined.

      In case of a 0°-polish this is not a problem since you can adjust for this by adjusting the axial lens position.

      However, in case of an SMA fiber connector with an angled polish, the emitting point additionally moves laterally with ferrule length.

      In order to compensate for this lateral displacement, a TILT alignment is absoluetely necessary. 

  • Troubleshooting FC PC and FC APC
    • I can‘t collimate the radiation out of a coupler. Why?
      • Have you loosened the grub screws?
        The clamp screws have to be loosened before changing the focus setting, Please refer to the adjustment instructions of the individual couplers for more details.
      • Have you checked, if the fiber is correctly placed within the fiber receptacle of the coupler?
        The fiber connector might not be placed correctly within the receptacle of the coupler. In particular, please check the small grub screw holding the connector's ferrule (e.g. for FC PC and FC APC type couplers). It might be in the way. Please refer to the adjustment instructions of the individual couplers for more details.
      • Have you tried another eccentric key?
        Please check, if the eccentric key is damaged or broken.

        Please also check, if you are using the appropriate eccentric key. The eccentric key type 60EX-5 has a larger stroke compared to the key type 60EX-4. The 60EX-5 is used for couplers with focal length ≥ 12 mm. The 60EX-4 is used for focal lenghts < 12 mm.

        In some very, very rare cases the stroke of the original eccentric key may be too small for the coupler in your applictation. (See FAQ "Difference between 60EX-4 and 60EX-5"). Try using the 60EX-5 in this case.
      • Have you checked the eccentric key for damage?
        The eccentric key might be damaged or broken. If that is the case, try another eccentric key of the same type and (or) contact Schäfter+Kirchhoff for replacement.
    • It says my coupler/collimator was "precollimated" but the collimation setting seems to not be alright. What might be the problem?
      • Are you using the same wavelength as the adjustment wavelength?
        Schäfter+ Kirchhoff ships all collimators prealigned and collimated for either a specific wavelength defined by the customer or a typical wavelength. The collimation is performed using professional collimating telescopes.

        The adjustment wavelength is given on the label for each collimator/coupler. If you are using another wavelength you need to change the focus setting. Please refer to the manual for more details.
      • Are you using the same fiber type as in the adjustment procedure?
        The fibers used in the standard adjustment procedure are all equipped with an end cap when aligning for wavelengths ≤ 520 nm. The adjustment wavelength is given on the label for each collimator/coupler. If a fiber with end cap was used it is marked by "EC".

        If you are not using a fiber with an end cap but the preadjustment at Schäfter+Kirchhoff was done using an end cap ("EC") or you are using a fiber with an end cap and the preadjustment at Schäfter+Kirchhoff was done without, you might need to change the focus setting. Please refer to the manual for more details.

Downloads

Adjustment_60FC.pdf (Manual)
Article_FibercouplingNAe2.pdf (Technote)

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

to attach in the front of collimators with system mount Ø 8 mm

for transforming a collimated beam into a micro focus spot
for collimators with Ø 12 mm
for attaching to 60FC Fiber Collimators

Retardation optics for fiber collimators with Ø 12 mm