Additive manufacturing of lensed fiber probes for wafer-level testing and improved optical coupling
Operational since 2017, since 2023 as Keystone Photonics.
Product Range
Custom Optics
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Lens with high NA for die-level laser and PIC testing. |
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Lens with low NA for die-level spot-size converter testing. |
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Large working-distance for wafer-level testing of grating couplers with well-defined best coupling position. |
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Collimated output with up to 30 μm MFD for coupling to other lensed devices. |
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Asymmetric lenses with 0° to 20° deflection. |
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90° deflection for wafer-level testing of edge-coupling devices in 100 μm trenches. |
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Large working-distance for extra clearance. |
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85° emission for better top-view camera vision. Other angles available upon request. |
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More options and design&simulation service available upon request. E.g. cryo compatible, extended wavelength range, anamorphic lens designs, metal-coated optics etc. |
Fiber Arrays
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Fiber arrays up to 64 channels |
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Lensed fiber arrays for both die and wafer level testing of angled facets (e.g. InP laser, SOA, SLED). |
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Any pitch, fiber type, mixed fiber arrays, PM fiber arrays, cryo, UV, VIS NIR fiber arrays are available upon request. Every channel of a fiber array can be equipped with different optics. |
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Range of 3D-printed markers for top- and bottom-view camera alignment. Suitable for surface and trench coupling. |
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Photonic integrated circuits (PIC) can be used as a means for pitch equalization or pitch reduction to 20 µm. Such probe heads allow testing of ultra-low pitch photonic integrated circuits both using grating and edge-coupled devices. PIC may be equipped with 3D-printed mirror optics or a straight lens.
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Custom Fiber Array Mounting
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Test & Validation
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Optional mode-field and transmission measurements. |
Our Applications
Wafer-level Testing
Mirrored lenses for trench coupling
Lenses for surface coupling
Astrophotonics
Lenses printed on multi-core fibers for astrophotonics
Cryo and Quantum Applications
Data Centers and Medical Devices
Request Form for Standard Products
Standard Corpus Types (µm)

Corpus type A

Corpus type B

Corpus type C

Corpus type D
Optional markers compatible with commercial probe stations

- All calculations were done with Gaussian approximation
- All MFD are specified at 1/e² intensity level
- MFDs correspond to UHNA4 and SMF28 fiber (except for smallest MFD)
- WD is measured from apex of lens to waist
- Measured coupling efficiency is pending, estimated coupling is 0.5 dB for large MFD,
1 dB for smallest MFD, TIR surface has 0.1-0.3 dB penalty
Our Technology in a Nutshell
Optical Wafer-Level Testing
Watch Keystone Photonics: 1 hour 23 minutes
Watch Keystone Photonics: 1 hour 42 minutes
Our jobs
We do not have open positions at the moment, but you can always send us an unsolicited application at jobs@keystone-photonics.com
Reliable and industry-proven fabrication services of validated photonic components for wafer-level testing and free-space coupling.