Lensed single-mode fiber arrays

Efficiently coupling light from photonic integrated chips (PICs) e.g. based on SiN, Si or InP technology requires a single-mode fiber (SMF) with a mode-field diameter (MFD) matched to the PIC. Our lensed fiber arrays can be either purchased on a 127 µm pitch SMF-array or a 250 µm SMF-array. We can supply lensed fiber arrays with MFD from 1.5 µm to 25 µm for a wavelength of 1310 nm or 1550 nm.

What are lensed fiber arrays?

Efficiently coupling light from photonic integrated chips (PICs) e.g. based on SiN, Si or InP technology requires a single-mode fiber (SMF) with a mode-field diameter (MFD) matched to the PIC. However typical SMFs have MFDs of around 10 µm while most PICs require MFDs in the range of few micrometers or below. To achieve mode matching, lensed-fibers or tapered fibers are used. These are SMF with either a lens or a taper melted or etched to the SMF. By this method neither length nor pitch of several SMF can be precisely matched to form an array of lensed SMFs.

To overcome this challenge we use V-Groove arrays, that have a well defined facet and pitch. We fabricate lenses onto this facet with 3D-microprinting based on two-photon polymerization. We are able to fabricate aspheric freeform lenses with highest reproducibility, also available as lensed SMF-arrays.

What performance can lensed fiber arrays deliver?
We have demonstrated that individual lensed fibers can couple InP lasers with losses of down to 0.6 dB into SMFs [1]. Losses to SOI chips are highly dependent on the taper. For standard 200 nm taper we expect losses of 3 dB with a penalty of approximately 2 dB if several lenses are to be coupled in parallel.
What specification can I order?

Our lensed fiber arrays can be either purchased on a 127 µm pitch SMF-array or a 250 µm SMF-array. We can supply lensed fiber arrays with MFD from 1.5 µm to 25 µm for a wavelength of 1310 nm or 1550 nm.

For configuration options, see table below:

table

Can I order custom optics on SMF-arrays?
Yes we can provide larger MFDs up to 25 µm as well as larger working distances, different wavelength or custom optics/fiber arrays, multi-core fibers and custom fibers and optics.
What power can the lenses withstand?
We could couple with powers of up to 3 W (35 dBm) at a wavelength of 1550 nm. Please note that this is close to destruction threshold, typical operation should be below 30 dBm at 1550 nm.

Further information

[1] P.-I. Dietrich et al. “Lenses for Low-Loss Chip-to-Fiber and Fiber-to-Fiber Coupling Fabricated by 3D Direct-Write Lithography,” in CLEO’16, OSA, 2016, SM1G.4.[2] S. Schneider et al. “Optical coherence tomography system mass-producible on a silicon photonic chip,” Opt. Express 24, 1573–1586 (2016).
Figure 1: Lensed fiber array with different 3D-printed lenses. The lenses can be printed with standard and custom specifications. (A) Lens with freeform surface. (B) Lens-90°-mirror comprising total internal reflection. (C) Electron microscopy image of different lenses on a V-groove array.

How can I order the lensed SMF-arrays?

Please mail at sales@vanguard-photonics.com and specify the product number, see table below. Please ask for customized optics.