A facet-attached micro lens (FaML) can be attached to an edge coupler using a two-photon lithography process to achieve low-loss coupling (<3 dB) to mode-matched microlens-attached fiber(s). The field emitted from the edge coupler is expanded from 3 μm to 25 μm to allow relaxed alignment for fast and easy coupling. The fabrication process is performed by Dream Photonics Inc. after the photonic integrated circuit chips have been fabricated by ANT. The edge coupler used for this process is designed by Dream Photonics Inc. and the deep trench etching process is required for the edge couplers. Additional qualities include low polarization-dependent loss (0.5 dB) and large bandwidth operation (>100 nm). The polymer of the microlenses is also rated for high power handling (>700 mW at telecom wavelengths), Telcordia Ref. 3.3.2.2: 225 cycles of -40°C to +85°C (>200 h), and Telcordia Ref. 3.3.2.3: 85°C/85% humidity, 3500 h. For more details, please see the FaML example.
