In a joint presentation by EXALOS and FIBER OPTICAL SOLUTIONS (FOS) at the 61th DGON ISA symposium, experts from both companies demonstrated a novel integrated 1550 nm 3-fiber SLED transceiver module and its application in a high-precision Inertial Measurement Unit (IMU) for navigation.
The symposium took place in Brunswick (Braunschweig), Germany at October 22-23, 2024, as a face-to-face event.

The advanced 14-pin Butterfly (BTF) module is realized with a micro-optical, free-space bench technology.

The broadband SLED emits an optical spectrum with 3dB bandwidth of 33 nm around a center wavelength of 1549 nm. The output is collimated into three output beams that are propagating through an optical circulator before being focused into an array of three PM output fibers. Efficient beam collimation and low-loss beam propagation on the optical bench in combination with high-efficiency coupling to the PM output fibers results in output power values of around 1.0 mW per fiber channel at low drive currents of only 150 mA.

Higher output power values are obtained at higher SLED drive currents. The polarization extinction ratio (PER) of each fiber port provides more than 15 dB.

Three integrated receiver photodiodes detect the returned light from the PM fiber loop of the corresponding FOG. The design provides low transmission loss as well as high isolation and, therefore, high wavelength and power stability against backward-propagating light.

All in all, the low-loss optical architecture in forward and backward direction offers power-efficient operation with low SLED drive currents and thus low TEC currents over the full temperature range from -40°C to +85°C.

The original, popular IMU required a wide range of discrete optical components, including depolarizers, fiber splitters or fiber-pigtailed photodiodes, as well as eleven splices of polarization-maintaining (PM) fibers.

The new innovative IMU design is based on the new integrated EXALOS SLED transceiver module. The 14-pin Butterfly (BTF) module delivers broadband light with similar optical power levels and with a high polarization extinction ratio (PER) at three PM output fibers.
This allows the direct splicing to the three phase modulators (MIOC), reducing the number of PM fiber splices to only three:

About EXALOS

EXALOS AG, an Indie Semiconductor company, is manufacturing state-of-the-art SLEDs and LDs in the visible and near-infrared wavelength range for a broad range of industries, including biomedical imaging, fiber optic gyroscopes, interferometry, machine vision, optical sensors, automotive, test equipment or other demanding applications. EXALOS is offering broadband SLED devices at various wavelengths, ranging from 400 nm to 1700 nm. The company has its headquarters in Schlieren, Switzerland.

Information on Exalos web-site

DGONs web-site

Fiber Optical Solution has received the ISO 9001:2015 certification for our inertial navigation systems production process. This certification highlights our commitment to quality and continuous improvement.

We thank our dedicated team and loyal customers for their support. This achievement strengthens our promise to deliver high-quality products and services.