Advantages of Multiple Band Pass Filters in Telecommunications Applications
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.
Wavelength budgeting for optical filters
Abstract: Considerations when specifying transition pass bands, blocking bands, and transition widths include filter manufacturing tolerances, thermal tolerances and source/detector variations among others. These factors must be taken into account properly and...Hybrid Gain Flattening Filters in Optical Fiber Amplifiers
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.
Effect of an optical coating on in-band and out-of-band transmitted and reflected wavefront error measurements
The wavefront error (WE) of a surface with an optical coating (“filter”) is ideally measured at the in-band wavelength of the filter. However, quite often this is not possible, requiring that the filter be measured at an out-of-band wavelength (typically 633 nm), assuming that the filter transmits (for transmitted WE, or TWE) or reflects (for reflected WE, or RWE) at this wavelength. This out-of-band TWE/RWE is generally assumed to provide a good estimation of the desired in-band TWE/RWE. It will be shown in this paper that this is not the case for a large class of filters (i.e., bandpass) where the group delay is significantly different at the in-band and out-of-band wavelengths and where the optical filter exhibits a thickness non-uniformity across the surface.
Edge Filters for Raman Spectroscopy
Raman spectroscopy probes the molecular vibrational and rotational modes of a material in order to detect and identify the material. Typically, laser light is incident upon the material and the scattered light is measured.
The excitation source (laser line) intensity is often to orders of magnitude greater than the Raman scattered signal. Therefore, edge pass (or notch) filters are required to block the Rayleigh scattered laser light while transmitting the red-wavelength shifted (Stokes) and/or the blue-wavelength shifted (Anti-Stokes) Raman scattered signal.
Messages From Above – Optical Satcom Lights the Way
We live in the “Communications Age” – rapid access to information and connectivity to each other, anytime, nearly everywhere. But despite the massive strides that have been made in the past half century – from hardline telephony to the current ubiquitous wireless “smart” device connectivity – there is still further evolution to come that will necessitate extending the communications reach even further. While we have laid down a large physical infrastructure of wireline fiber-optic networks and wireless cellular base stations, the next advances in communications, 5G and machine-to-machine communications, will require “help from above” to blanket literally every corner of our planet with high speed, ultra-low latency, secure networks – telecom meet satcom.
Remote Sensing With LiDAR Requires Optical Filter Trade-Offs
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.
Conflict Minerals Policy Statement
Section 1502 of the Dodd-Frank Wall Street Reform and Consumer Protection Act, and the Securities and Exchange Commission Rules adopted in connection therewith, require certain corporations to report the use of “Conflict Minerals” in the manufacture of...光学フィルターのクリーニング方法
光学フィルターのkりーにんぐ方法。 イリディアンのフィルターはハードコーティングされたフィルターですが、デリケートでもあるため、他の光学部品と直接接触することを避けるか、または最小限に抑えるように注意しながら取り扱う必要があります。 イリディアンのフィルターは全て、下記に推奨する方法でクリーニングすることができます。
How to Specify Surface Figure and Wavefront Distortion for Multi-layer Optical Filters
Optical filters are used in many applications and the surface figure and wavefront distortion requirements of filters are dependent on where and how they are used. Whereas band-pass or clean-up functionality may only require control of the transmitted wavefront, dichroic beam-steering/splitting filters or wavelength selective mirrors likely require specification of both the transmitted and reflected beams. If filters are only used in sensing applications with very tolerant detector geometries, there may be no need, in practice, to put any constraints on the surface figure or wavefront distortion. It is important to understand where, when, how, and how much to specify wavefront distortion to ensure that functional requirements are guaranteed while unnecessary and costly constraints are avoided.
LiDAR and Optical Filters for Autonomous Vehicles
“What’s a ‘steering wheel’?” At the present time this would be a very strange question to hear asked from anyone who has driven, ridden in, or even seen a car but in a couple of decades this may not seem so unusual. The evolution of increasingly affordable and capable sensing and imaging systems combined with the desire to create safer, more efficient transportation systems is driving the development of autonomous vehicles (pun intended). LiDAR is a key technology that will eventually help carry this growth through to “Level 5” autonomy : no steering wheels, no brake pedals, no human intervention in driving.