SELFOC® MICRO LENS(SML), Standard

There are two categories of lenses, both distinguished by a different numerical aperture:
SLW (wide) and SLH (high). Each NA type is appropriate for different applications andexhibits different alignment sensitivities.
While the numerical aperture is a maximum at the center of the lens aperture, the actual
NA is a function of the ray parameters (height and angle) for each ray that strikes the lens’Surface (see technical note for detail).
C18 is optimized for Single Mode Fiber application to have better coupling efficiency. So,when you consider the usage of SMF, C18 have better Insertion Loss performance than
W18.

Applications:••••

Laser diode-to-fiber coupling
Fiber-to-detector coupling
Fiber-to-fiber coupling
Focusing and collimating

Optical Parameters:
Lens TypeDiameter
Wavelength

W10

W18

W20

C18

H18

Φ1.0mm

Φ1.8mmΦ2.0mm

Φ1.8mm

Φ1.8mm

0.46 (55°)

NA (2θ)1.607

N0630nm

0.339

0.304

-

0.430

Z @0.25P

2.58mm

4.63mm

5.17mm-3.65mm

-

1.646

1.599

√A

0.601

0.332

0.298

-

0.423

Z @0.25P

2.61mm

4.73mm

5.27mm-3.71mm

1.592

1.636

1.592

√A

0.597

0.327

0.295

0.324

0.418

Z @0.25P

2.63mm

4.80mm

5.32mm

4.85mm

3.76mm

1.590

1.634

1.590

N01550nm

1.658

0.608

N01310nm-√A
N0830nm0.60 (74°)

√A

0.596

0.326

0.294

0.323

0.417

Z @0.25P

2.64mm

4.82mm

5.34mm

4.86mm

3.77mm

NA: Calculated value on axis
N0： On-axis refractive index / not garanteed
nominal vaue
√A： Index gradient constant
Z： Lens length with 0.25 pitch at lens center, nominal value

Common Characteristics :Item

Specification

Notes

Transmittance

89% min.

Wavelength : 380-2000nm, 5mm, uncoated

Polarization Preservation

0.99

Non-stressed state

Effective diameter

Approx. 60-70% of lens DiameterIndex Gradient Constant√A Tolerance±2.5% max.

Between ion exchange batches±0.75% max.

Within same ion exchange batch+0.005/-0.01mm

For all SMLs except SLW3.0 and 4.0+0/-0.02mm

For SLW-3.0 and SLW-4.0Lens Length Tolerance+0/-0.04mm

Machining and polishing tolerance

End Facet Perpendicularity

6 mrad. max.

Ellipticity

3um

Glass MaterialOxide Glass

Young's Modulus

6000 - 8000 Kgf/mm 2

Lens Diameter Tolerance

Thermal Expansion Coefficient

10 x 10Dmax-Dmin
TypicalTypical-6/℃

Surface Quality (inspected at x20 mag.) :Item

Specification
Defects greater than 30um in deameter are not allowed.
Pinholes / Particles Defects smaller than 10um in diameter are allowed.
Up to three defects with diameter between 10um and 30um are allowed.
Scratches wider than 5um are not allowed.
Scratches
Scratches narrower than 2u are allowed.
Up to three scratches with 5um max. width and 200um max. length are allowed.
Chippings
Chippings are not allowed within the concentric area of 90% of the lens diameter.

Options :Metallization
Metallization of the side surface allows the user tosolder the lens into a housing. The purpose is tocreate a hermetic seal and to provide greaterbonding strength than epoxy bonding.
We have 2types of Metallization, one is M-Meta thatis good for Pb/SN solder(relatively old solder) andother is U-Meta that is good for Au/Sn solder(hightemperature).

Item / Type
Application

M-TypePb/Sn Solder

U-TypeAu/Sn Solder

Configuration

Cr : 500 + 150Å
Pt : 500 + 150Å
Au : 6000 + 1000Å

Ti : 1000 + 200Å
Pt : 1500 + 200Å
Au : 5000 + 1000Å

Max. SolderTemperature

230℃ x 10sec

380℃ x 120sec(in Nitrogen)AR CoatingAR coating reduce the amount of light lost due toFresnel reflection at the lens surfaces. They also
help to protect the lens surfaces from humidity,
chemical reaction, and physical damage. Five
grades of coating(S, K, U, H, D) are available, eachwith its unique characteristics. The coating areoptimized for specific wavelength(s).
Item / Coating TypeWavelength range
Maximum Refection
per surface
Coating Structure
Maximum Temperature
Maximum Humidity
and Reliability

None-Coated

S-GradeU-GradeK-GradeD-GradeH-Grade830 + 15nm&
1310 + 30nm

980 + 30nm&
1550 + 30nm

-630nm + 15nm 1310nm + 30nm
830nm + 15nm 1550nm + 30nm

600 + 200nm

1400 + 200nm

4 ~ 6%

0.25%

1.50%

0.20%

350℃
Not recommended
for high humidity

Typical AR Spectrum

Multilayer Metal Oxide
200℃ x1000hrs
85℃/85%RH 1000hrs

0.50%

Angled Facet
Angling one or more of the lens facets caneffectively reduce back reflection from thesurface(s). This option is available for all SELFOC
Microlens (SML) with OD of 1.0, 1.8 and 2.0mm.
There are two types of angled facets available. With
the Single-Angle option, one lens facet is tilted while
the other remains perpendicular to the optical axis.
With the Double-Angle Option, we can offer‘Parallelogram’ that is both facets are tilted
identically such that they remain parallel to eachother and ‘Trapezoid’ that is. Back reflection can be further minimized with theuse of AR coating.

Ordering Guide: