Hybrid-Integrated Tunable Hollow Waveguide DBR Laser
We propose a novel hybrid-integrated tunable laser with a hollow waveguide distributed Bragg reflector, enabling a wide continuous tuning with a single-tuning parameter. The wavelength tuning of hollow waveguide lasers is demonstrated for the first time.
A hollow waveguide Bragg reflector: A tunable platform for integrated photonics
Abstract Hollow waveguides are promising candidates for applications in sensing and high-power transmission. Flexible design and cost effective fabrication of hollow waveguides make it possible to realize integrated devices with small temperature dependence, tight control on optical confinement and tailorable characteristics. One of the potential applications of hollow waveguide is a tunable Bragg reflector, which can be used as building block for integrated photonics. In this review, integrated tunable Bragg reflector based on hollow-core optical waveguide is reviewed and presented; this Bragg reflector offers variable characteristics and design flexibility for applications in reconfigurable integrated photonic devices and circuits. Variety of tunable optical functions can be realized with on-chip Bragg reflector based on hollow waveguide, few of them are discussed in this review. Ultra-wide tuning in Bragg wavelength and on-chip polarization control can be realized using 3D hollow waveguide. A tapered 3D hollow waveguide Bragg reflector for an adjustable compensation of polarization mode dispersion (PMD) is then discussed. The utilization of a high-index contrast grating in hollow waveguide is demonstrated to reduce the polarization dependence and reflection-bandwidth. The polarization- and bandwidth control may be useful for realizing polarization insensitive devices and semiconductor lasers with ultra-wide tuning.
Fluid to liquid membrane energy exchanger for simultaneous liquid desiccant regeneration and desalination applications–Theoretical and experimental analyses
Abstract In this paper, a thermal model developed for assessing the performance of the fluid to liquid membrane energy exchanger based liquid desiccant regenerator is presented. The model was validated with the experimental data and found accurate. Using the experimental inlet conditions reported in the literature for the structured packing chamber, the performance of the fluid to liquid membrane energy exchanger based liquid desiccant regenerator was theoretically predicted choosing water and air as working fluids and Lithium Chloride as a liquid desiccant. Further, studied the influence of inlet parameters such as working fluid and desiccant inlet temperature’s, hot liquid desiccant to cold working fluid ratio and desiccant concentration on vapour absorption rate. From this analysis, it is observed that membrane based liquid desiccant regenerator using water as a working fluid is best suitable for converting the weak desiccant into strong desiccant and for generating the pure water simultaneously (co-generation process). An experimental investigation was carried out for assessing the energy exchange process across the membrane based liquid desiccant regenerator using water as a working fluid. From the experimental analysis, it was found that desiccant temperature has a significant impact on the energy exchange process. The pressure drop across the membrane based liquid desiccant regenerator was also measured at different desiccant flow rates and concentration.