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Terahertz-frequency quantum-cascade lasers (THz QCLs) are compact, electrically-driven sources of narrowband radiation in the ~2–5-THz band. Numerous scientifically important gas-phase species within the Earth’s upper atmosphere have distinctive spectral features within this band, making QCLs attractive sources for spectroscopic and radiometric atmospheric studies. In this paper, we demonstrate the integration of a QCL with a satellite-compliant cryocooler, precision-micromachined waveguide, a pair of diagonal feedhorns and a Cassegrain telescope, as key steps toward a complete 3.5-THz integrated receiver system.

We report on ongoing technology activities on the Elegant Breadboard for the LOCUS telescope and its 1.15THz receiver. LOCUS is a Low-Earth orbit small satellite (150kg category) with the objective of linking observations of climate, the upper atmosphere and space weather by performing simultaneous high spectral resolution measurements of molecular signatures of molecules which drive the thermal exchange in the highest layers of our atmosphere. These measurements are performed both in the THz frequency region and in a photometric narrow-band near and mid-IR channels allowing to decouple molecular abundances from temperature and pressure profiles. The elegant breadboard under development will reproduce representative optics and explore the thermal implications of a compact optical-bench with a small cryo-cooler and radiator stage for a small LEO satellite. An extensive test programme will be undertaken to raise the payload and receiver system and we will seek opportunities to test the system in an observational campaign. Technology developments will benefit future technology activities related to both a future Earth-Orbit mission and potential astronomy missions.

This paper describes how design rules are established for photolithographically manufactured acrylate polymer optical multimode waveguide components by optical experimental measurements made on the manufactured waveguide component. The loss of individual waveguide components, such as straight sections, 90deg bends, crossings, tapers and tapered bends must be known so that the combined loss of a cascade of such elements can be found to determine whether the interconnectionpsilas optical power budget is sufficient to achieve a good bit error rate. However, the loss depends on several factors: the materials: the polymer used for the core and for the cladding, the fabrication technique: e.g. the photolithographic procedure and the precise temperature baking regime used, and the measurement technique: the optical source lateral size and angular divergence and precise position relative to the entrance of the waveguide, the output detector lateral size, its angular acceptance angle (if any) and its precise position relative to the exit of the waveguide. The experiments reported on photolithographically manufactured acrylate polymer multimode waveguide were performed at room temperature. A new technique for measure the transmitted power at waveguide crossings is reported for the first time.

This paper reports numerous experimental measurements and modelling result of the loss caused by various amounts of translation and rotation misalignment in the optical backplane system. Combinations of VCSEL as the light source and waveguides of various widths have been input in the system. The source has been moved away from the centre of a channel waveguide in the horizontal and vertical direction gradually to find out the translation and rotation tolerance. Offsets between VCSEL-waveguide and waveguide-receiver have been studied to find the translation and rotation tolerance.

BPM modeling establishes a set of design curves for coupling loss of a VCSEL optical source for several widths of square multimode polymer waveguides giving the interdependence of lateral and axial offset misalignments.