SELFOC® MicroLens SELFOC MicroLenses are ideal for many signal transmission and focusing applications. Some typical uses are listed as follows: Laser diode-to-fiber coupling Fiber-to-detector coupling Fiber-to-fiber coupling Focusing and collimating There are three categories of lenses, each distinguished by a different numerical aperture: SLS (standard), SLW (wide), and SLH (high). Each NA type is appropriate for different applications and exhibits different alignment sensitivites (see table 2). While the numerical aperture is a maximum at the center of the lens aperture, the actual NA is a function of the ray paramenters (height and angle) for each ray that strikes the lens' surface. Click to the Appendix of this guide for an illustration of how the NA depends on these parameters. MicroLens Options Proper handling and storage of lenses. Table 1 Common Characteristics   ITEM SPECIFICATIONS NOTES O P T I C A L Transmittance 89% minimum 380 - 2000 nm wavelength range Polarization Preservation 0.99 Non-stressed state Maximum Pitch 0.75P Lens length Z = 2pP / ÖA Lens Effective Diameter approx. 60 - 70% lens diameter For low loss and low aberration Index Gradient Constant ÖA Tolerance +/- 0.75% max. Within same ion exchange batch +/- 2.5% max. Between ion exchange batches M E C H A N I C A L Lens Diameter Tolerance +0.005 / -0.010 mm Excluding SLW-3.0 and 4.0 +0 / -0.02 mm For SLW-3.0 and SLW-4.0 Lens Length (Z) Tolerance * +/- 2.5% of nominal length Adjusted according to ÖA variation +0/-0.04 mm (vs.calculation) Machining and polishing tolerance Minimum Lens Length 1.0 mm for non-coated lenses 2.3 mm for AR coated lenses   Facet Perpendicularity 6 mrad max.   Ellipticity 3 µm Dmax - Dmin Glass Material Oxide Glass   Young's Modulus 6,000 - 8,000 Kgf / mm2 typical Thermal Expansion Coeff. 10 x 10-6 / °C typical OTHERS Temperature 350 °C max. operating temp. for lens material Humidity (Will react with non-coated lens) Store in dessicant to avoid moisture. See inner cover for Storage/Handling. Radiation (Varies by dose and wavelength) Contact NSG for reference data SURFACE QUALITY ** inspected at 20X mag. Pin Holes / Particles Defects greater than 30 µm in diameter are not allowed. Defects smaller than 10 µm in diameter are allowed. Up to 3 defects with diameter between 10 µm and 30 µm are allowed. Scratches Scratches wider than 5 µm are not allowed. Scratches narrower than 2 µm are allowed. Up to 3 scratches with 5 µm max. width and 200 µm max. length are allowed. Chips Chips are not allowed within the concentric area of 90% of the lens diameter. * Total lens length (Z) tolerance includes variations from both ÖA and machining/polishing. ** The Surface Quality Specs apply to complete, round, flat end surfaces perpendicular to the cylindrical axis of the lens. It does not apply to the flat portion of the angled end surface.   Table 2: Standard Lens Specifications SML Type Applications/Features On-Axis N.A. Diameter(mm) Standard Pitch(es) Standard Wavelength (nm) SLH "High" field of view (74°), Coupling of source/detector to optical fiber, Small beam diameter 0.60 1.8 0.25   SLW "Wide" field of view (55°), Best general purpose lens 0.46 1.0 0.25 1.8 0.18, 0.23, 0.25, 0.29 2.0 0.25 3.0** 0.11, 0.25 780 4.0** 0.11 * For SLS-2.0, specify SMF (singlemode) or MMF (multimode) applications as a special feature, see Ordering Information. ** SLW-3.0 and SLW-4.0 lenses with 0.11 pitch are tested for wavefront quality. See section on Specialty Lenses for further details. Table 3 Optical Parameters Wavelength Type SLW SLH N.A.(2q) 0.46 (55°) 0.60 (74°) Dia. (mm) 1 1.8 2 3 4 1.8 630 nm N0 1.6073 1.6354 1.6576 ÖA 0.608 0.339 0.304 0.207 0.154 0.430 Z (0.25P) 2.58 4.63 5.17 7.60 10.24 3.65 830 nm N0 1.5986 1.6249 1.6457 ÖA 0.601 0.332 0.298 0.203 0.151 0.423 Z (0.25P) 2.61 4.73 5.27 7.75 10.43 3.71 1060 nm N0 1.594 1.6194 1.6394 ÖA 0.599 0.329 0.296 0.201 0.149 0.419 Z (0.25P) 2.62 4.77 5.31 7.85 10.54 3.74 1300 nm N0 1.5916 1.6165 1.6360 ÖA 0.597 0.327 0.295 0.199 0.1483 0.418 Z (0.25P) 2.63 4.8 5.32 7.89 10.59 3.76 1560 nm N0 1.5901 1.6147 1.6340 ÖA 0.596 0.326 0.294 0.199 0.1478 0.417 Z (0.25P) 2.64 4.82 5.32 7.89 10.63 3.77 Note: Standard wavelenth for SLW-3.0/4.0 is 780 nm.   Ordering Information Example: Type Diameter Pitch Wavelength AR Coating; Metallization Special Features SLW 180 025 156 A2M 8D AR Coating: A2, C1, etc., NC = Non-coated (see SML Options for details). Metallization: M = Metallization, 0 = Non-metallized (see SML Options for details). Special Features: e.g., SMF or MMF for SLS-2.0; 8D = 8° Angled Facet, etc. (see SML Options for details).