LiDAR, short for light detection and ranging, uses pulsed lasers to accurately calculate distances as well as correctly detect the size and shape of objects. The high resolution of the information — LiDAR can resolve to a few centimeters from more than 100 meters away — and the ability to create accurate model three-dimensional images have made the technology critical in many applications. Some uses include autonomous vehicles and automobile crash avoidance, surveying, environment, construction, agriculture, oil and gas exploration, and pollution modeling.

In wavelength-division multiplexer (WDM) and passive optical network (PON) modular design, single band pass filters and multiple band pass filters are used for the same purpose: permitting narrow wavelength ranges to pass through while rejecting wavelengths outside that range (known as the filter’s upper and lower cutoff frequencies).

Multiple band pass filters are used to transmit two or more standard coarse wavelength division multiplexing (CWDM) channels, separating them from the other CWDM bands — replacing two or more single band pass filters with a single component.

Much like vehicle hand cranks in their day, the use of a gain flattening filter (GFF) paired with a wavelength- division multiplexer (WDM) in optical fiber amplifiers – such as erbium-doped fiber amplifiers (EDFA) — has been accepted not because it is ideal, but because a superior solution had yet to be created. Until now.

This article explains what a Hybrid GFF is and how it works. It also details the advantages of using Iridian Spectral Technologies’ Hybrid GFFs in lieu of a conventional two-filter setup in EDFA and other optical filter applications.