Freedom Photonics proposes the development, demonstration, and commercialization of a watt-class 1550 nm superluminescent diode (output power >1000 mW). Our design will produce a wide spectral bandwidth (>50 nm) with a highly symmetric, low-ripple, near-Gaussian spectral shape. The device will be packaged into an industry-standard hermetically-sealed 14-pin butterfly package and coupled to a polarization-maintaining single mode fiber for direct deployment into fiber optic interferometric systems. The package will include an integrated thermoelectric cooler and optical isolator. The reliability of the superluminescent diode is expected to greatly exceed 30 years and will be well suited for terrestrial and aerospace deployment. Our design approach leverages our industry-leading capabilities around high efficiency 1550 nm epitaxial design and high power 1550 nm diffraction-limited diode lasers. The proposed architecture is novel and offers several key benefits over traditional SLD sources including: 1) order-of-magnitude increased output power, 2) greatly improved power conversion efficiency, 3) inherent robustness to optical feedback, 4) greater wavelength tunability at constant output power, and 5) wavelength flexibility.
Benefit: The DoD applications of our proposed design include interferometric fiber optic gyroscopes (IFOGs) and accelerometers for use in strategic-grade high precision inertial sensors. For this application, the inherent wide optical bandwidth and spectral symmetry of superluminescent diodes (SLDs) are highly advantageous compared to the narrow and asymmetric spectral bandwidth of traditional laser diodes. However, the relatively low available output power of present SLD technology restricts the performance and package size of IFOGs, limiting their deployability in the field. Our proposed approach will enable an order-of-magnitude increase in SLD power compared to the present state of the art. This will allow miniaturization of the IFOG system sense coils which will ultimately lead to improved performance and reduction in system SWaP-C. Our device architecture is also ideally suited for dual-use applications in optical coherence tomography.
Keywords: inertial sensor, inertial sensor, Superluminescent Diode, Fiber-Optic Gyroscope, light emitting diode, SLD, Navigation, high power, 1550 nm
