Spot Size Converting Fiber Arrays

Spot size converters (SSCs) provide an efficient coupling from arrays of optical fibers to photonic integrated circuits (PICs). They reduce the mode field using lithographically defined tapered waveguides.

PHIX offers v-groove fiber arrays with a pre-attached silicon nitride (SiN) SSC. They cater to a variety of channel counts, mode field sizes and shapes, pitches, waveguide angles, etc., and they can be interfaced to PICs of many common materials.

Traditional ways to reduce the mode field of an optical fiber are the use of ultra-high numerical aperture (UHNA) fibers, lensed fibers or specially tapered fibers. These solutions work well for single fibers, but they provide serious alignment challenges when applied to multi-channel configurations. Variations in core concentricity and cladding diameter would inevitably result in high losses.

Our SSCs, on the other hand, offer a low-loss multi-channel solution. They exhibit lithographic accuracy at the chip interface and therefore demonstrate a minimal waveguide to waveguide loss. PHIX SSCs are manufactured at wafer level and attached to our fiber arrays using an automated process. 

Some of our spot size converters have angled waveguides and elliptical mode fields suitable for coupling to indium phosphide (InP) PICs. We have standard options that are compatible with InP MPW runs by Smart Photonics. 

Features

• Low-loss silicon nitride (SiN) waveguides
• Circular or elliptical output mode field sizes between 1.5 and 3.4 µm
• Conversion loss less than 1.5dB
• Polarization maintaining
• Options available for C-band and O-band wavelengths
• Pitches of 125, 127, or 250 µm, or custom down to 10 µm
• 16, 32, 48, and 64 channels available off the shelf
• 0º or 8º top-down facet angles