Generally, components that adjust an optical beam’s diameter whilst maintaining a parallel output are called collimators. When the beam is convergent it is called a ‘focuser’. Users of optical fibres face two traditional problems; light injection, and beam shaping. These two related phenomena are very different. Here at LASER COMPONENTS we have solutions for both pigtailed collimators, and focusers.
These components are built by adjusting a fibre at the back focal point of a lens and protected within a standard or custom package. Depending on your specifications and the type of fibre required, we will select the appropriate lens. The lens would be either a ‘Selfoc (GRIN: Graded Index)’, ‘plano-convex’, or ‘aspheric’ lenses.
‘Selfoc’ lenses are cylinders of graded index silica, with the back of the focal point close to the glass. The pigtail assembly is achieved by bonding the fibre to the lens. The performance of the collimator is in direct relation to the dimension of the lens that is matched with the operating wavelength. Back reflections are improved with selected angles and optional anti-reflection coatings. ‘Selfoc’ lenses have a standard beam diameter of 300 to 400 μm and are mainly used for single mode and graded index fibres. Sometimes they are used to reduce the numerical aperture of step index multi-mode fibres (for example HCS 200 fibre).
Many requested specifications require the use of plano-convex or aspheric lenses for high power, large beam, specific working distance applications. These particularities require the development of adapted devices with the appropriate lens and specific packaging.
MAIN SPECIFICATIONS
- Fibres: standard or special SM, GI
- Typical beam diameter: 0.4 mm
- Total angle divergence: < 0.3°
- Insertion loss (fibre to fibre): < 0.7 dB
- Return loss without AR: 14 dB
- Power: max 300 mW
- MP fibre, polarisation axes: +- 3°
- Isolation: 20 dB
- Packaging:-
Large housing L 200 mm x Ø 6.35 mm
Compact housing L 200 mm x Ø 2.5 mm
Plug housing FC ferrule (2.5 mm)
