<title>High-channel-density broadband wavelength division multiplexers based on periodic grating structures</title>

Abstract

High channel density broadband wavelength division multiplexers (WDMs) based on periodic grating structures are discussed. These so-called single-window WDMs transmit a large number (> 100) of independent wavelength channels through a single fiber and within a single fiber communications window in both singlemode and multimode fiber cases. In this paper, singlegrating WDMs are analyzed in the context of the fundamental relation between channel density, crosstalk, power budget, and diffraction limited beam propagation. Also, the practical aspects of WDM-based fiber optic networks for high-speed (broadband) multi-media communication are discussed.

An easy packaging hybrid optical element in grating based WDM application

“…The filling ratio in this work, only 0.13 by 9 m SMF core in 65 m increments, is smaller than the general optimized value, around F=0.6. [9] Furthermore, applying a tapering waveguide or re-shaped fiber end can achieve a more suitable filling ratio which can modify a wider passband. [10] Because this WDM device has only two modules, this tolerance is suitable for the general manufacturing specification, thus the total error of the prism angle could be as high as +/-0.5°.…”

Design of hybrid free-space wavelength-division multiplexers for integration

“…It was a well-known fact that the average spatial distance among input and output optical channels of a MUX limits its physical volume [9,10]. This distance parameter is kept minimum in good practices, for example, by using a waveguide concentrator for grating-based MUX's [7].…”

“…The output may connect to fiber bundles. A concrete example of the 3-D hybrid MOWI is the waveguide concentrator ( Figure 2) [9,10]. However, we focus on the exploration of a more general structure for realizing a CWDM without using a bulk lens.…”

Athermalized low-loss echelle-grating-based multimode dense wavelength division demultiplexer

“…In this case, the optimized value of this ratio is F ϭ 0.667. 24 To increase the optical passband, we inserted a specially designed optical element for expanding the mode field diameter of output light spots into the optical system showed in Fig. 4.…”