Optical communications in the mid-wave IR spectral band

Abstract

The mid-wave IR (MWIR) spectral band extending from 3 to 5 microns is considered to be a low loss atmospheric window. The MWIR wavelengths are eye safe and are attractive for several free-space applications including remote sensing of chemical and biological species, hard target imaging, range finding, target illumination, and free-space communications. Due to the nature of light-matter interaction characteristics, MWIR wavelength based systems can provide unique advantages over other spectral bands for these applications. The MWIR wavelengths are found to effectively penetrate natural and anthropogenic obscurants. Consequently, MWIR systems offer increased range performance at reduced power levels. Free-space, line-of-sight optical communication links for terrestrial as well as space based platforms using MWIR wavelengths can be designed to operate under low visibility conditions. Combined with high-bandwidth, eye-safe, covert and jam proof features, a MWIR wavelength based optical communication link could play a vital role in hostile environments.A free-space optical communication link basically consists of a transmitter, a receiver and a scheme for directing the beam towards a target. Coherent radiation in the MWIR spectral band can be generated using various types of lasers and nonlinear optical devices. Traditional modulation techniques are applicable to these optical sources. Novel detector and other subcomponent technologies with enhanced characteristics for a MWIR based system are advancing. Depending on the transmitter beam characteristics, atmospheric conditions may adversely influence the beam propagation and thereby increasing the bit error rate. For satisfactory transmission over a given range, the influence of atmosphere on beam propagation has to be analyzed. In this chapter, salient features of atmospheric modeling required for wavelength selection and performance prediction is presented. Potential optical sources and detectors for building a practical MWIR communication link are surveyed. As an illustration, the design configuration and experimental results of a recently demonstrated free-space, Optical communications in the mid-wave IR spectral band 559 obscurant penetrating optical data communication link suitable for battlefield applications is discussed. In this case, the MWIR wavelength was derived using an all solid-state, compact, optical parametric oscillator device. With this device, weapon codes pertaining to small and large weapon platforms were transmitted over a range of 5 km. Furthermore, image transmission through light fog, accomplished using this hardware, is also presented.Advances in source and detector technologies are contributing to the development of cost effective systems compatible with various platforms requirements. In coming years, MWIR wavelengths are anticipated to play a vital role in various human endeavors.

Integrated photonic materials for the mid‐infrared

“…Free‐space optical communications utilize high immunity to atmospheric turbulence when implemented at the mid‐IR wavelength region 166 . Atmospheric attenuation and scintillation play a significant role in free‐space, line‐of‐sight optical communication links.…”

ANALYTICAL MODELING OF AlGaAs/GaAs VERTICAL CAVITY SURFACE EMITTING LASERS (VCSELS) OPERATING AT 850 nm FOR FREE-SPACE OPTICAL COMMUNICATION

“…The free-space optical communication (FSOC) is favorite because of the availability of low loss atmospheric transmission windows in several spectral ranges [1]. The advantage of free-space optical communication includes high bandwidth, eye-safe, license-free operation, high transmission security, protocol transparency, jam-proof and error-free link.…”

NUMERICAL SIMULATION OF MID-INFRARED DOUBLE HETEROSTRUCTURES LASER BASED ON InAsSb/InAsSbP MATERIAL SYSTEM

“…There are number of low absorption atmospheric windows (2-2.5 μm and 3.5-4 μm) in the mid-infrared (MIR) spectral region enabling one to setup free space optical communication link [1,2]. The advantages of the free space optical communication includes high bandwidth, eye safe operation, license free service, high transmission security, protocol transparency, jam-proof and error free link [1]. The sources for free space optical communication system require narrow bandgap semiconductor materials for their fabrication [3].…”