Photonics-based Systems Are Ready For The Mission
•Brochure: Mission-Ready
Fiber optic and photonic technologies offer enhanced RF and electrical technical performance benefits over traditional copper and coaxial cable systems plus almost unlimited bandwidth and distance. RF over Fiber systems are the obvious choice for existing and next generation Military and Defense battlefield, airborne and shipboard platforms.
High dynamic range, low noise and unprecedented communications security (COMSEC) covering low frequency (3-30 Kilohertz) to extremely high frequency (>30 Gigahertz) radiofrequency spectrum is the hallmark of photonicsbased systems. Fiber optic network topologies include linear, ring, bus, and wavelength add-drop architectures (WDM, CWDM, DWDM and OADM) with redundant path features, such as counterrotating rings, that allow flexibility in system design and rapid deployment for advanced, mission-critical fiber based RF communications, emitter location, telemetry, radar calibration, jammingcountermeasures and Electronic Support Measures (ESM) for airborne, ground-based and naval shipboard platforms.
Most analog optic or RF over Fiber networks today use standard singlemode (monomode) fiber cable as the optical waveguide. Fiber optic cable and the associated analog optoelectronics equipment have many advantages including very high linearity, low transmission loss, low weight, flat wideband frequency response, stable operation over extreme temperatures and excellent phase noise performance over temperature extremes from low frequencies to EHF. Two kinds of laser diodes are predominantly used today for analog, broadband transmitters: Directly modulated Fabry-Perot (FP) and Distributed Feed-Back (DFB) lasers in either direct and externally modulated configurations. Additionally, there are a couple different versions of DFB lasers—thermoelectrically (TEC) cooled and not cooled. For military and defense systems that require operation at temperature extremes, the cooled-DFB laser is preferable for guaranteed and predictable performance over temperature. These lasers traditionally operate at 1310nm (1.3?m) or in the 1550nm (1.5?m) window (C band: 1525~1562nm and L Band: 1570~1615nm). As photonic technologies advance, new bands are being introduced by the International Telecommunication Union (ITU), based in Geneva, Switzerland. Lasers that operate in these bands are commonly called "ITU-grid" lasers. Optical receivers typically employ positive intrinsic negative (PIN) and avalanche (APD) photodetectors for low noise, high gain optical to electrical signal conversion. RF over Fiber systems typically deploy industry standard fiber such as Corning SMF-28™ for most applications. Photonuum is researching into technologies and techniques that will convert multimode (MM) signals into singlemode for certain applications—this is beneficial for legacy systems that were deployed initially with multimode fiber.
Fiber optic systems can transport RF signals over kilometers with minimal loss and can be engineered for unity gain RF links. Low Noise Amplifiers (LNAs) can be implemented to raise the RF signal above the laser noise and post RF amplifiers can be used to overcome any optical link loss and to add signal gain at the far end receive site. As the signal propagates over the fiber cable there is a 1:2 relationship regarding optical loss (dBo) and electrical loss (dBe). For example: If a fiber link is approximately 12 kilometers in length, the optical loss at 1550nm will be around 3dB (0.25dB/per kilometer x 12 kilometers) The physics translates this to an electrical loss of 6dB (or 6dBo) in system gain.
For battlefield, airborne and shipboard Electronic Warfare (EW) and radio communications platforms, weight and cable size reduction is crucial. RF over Fiber links offer the greatest size and weight savings without sacrificing the performance required for military and defense mission-critical systems.
Photonuum Inc.'s selection of products come in a variety of form factors including flange-mount modules, 1U subsystems, 3U Universal Chassis hot-swappable module configurations or weather-proof NEMA solutions. The units can be wall or rack-mounted in a 19-inch rack with 120/240 VAC or DC powering options. Weather-proof NEMA solutions are available and boardlevel products can be tailored to specific needs.
SOURCE: Photonuum
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•Brochure: Mission-Ready