What is acousto-optic tunable filter?
The acousto-optic tunable filter (AOTF) is an electro-optical device that functions as an electronically tunable excitation filter to simultaneously modulate the intensity and wavelength of multiple laser lines from one or more sources.
Which of the tunable filter is most suitable for DWDM?
Up to date, the most commonly used tunable filter structures are interferometric such as Fabry-Perot (FP) and Mach-Zehnder (MZ) interferometers[1]. They are usually poor in the performance of passband flatness and the crosstalk, and require robust electronics to stabilize the central wavelength.
How does an acousto-optic modulator work?
How Does an Acousto-Optic Modulator Work? Acousto-optic modulator typically uses a transparent crystal or piece of glass as a medium for light propagation. An electric signal then drives an attached transducer to vibrate, therefore generating a sound wave within the cell.
What are acousto-optic devices?
Acousto-optics is a versatile technology that allows users to precisely and rapidly control the wavelength, amplitude and propagation direction of a laser beam. These capabilities are proving popular in applications as diverse as agriculture, entertainment and defence.
What are acousto-optic modulator used for?
An acousto-optic modulator (AOM) is a device which can be used for controlling the power of a laser beam with an electrical drive signal.
What is Raman-Nath theory?
At sound frequencies of a few megahertz and lower, Raman-Nath theory determines light diffraction by sound if the interaction length is no longer than about 35 cm. Imaging rules under Raman-Nath conditions are nearly the same as corresponding rules for imaging under Bragg conditions.
What is the purpose of acousto-optic modulator?
What is DWDM filter?
Application. Dense wavelength division multiplexing (DWDM) filters multiplex and de-multiplex wavelength signals in high speed optical networks. The DWDM filters are evenly spaced on an ITU grid ranging from 1525 to 1640 nm. Single band filters are used to transmit a single DWDM channel and reflect other DWDM channels.
How does an optical filter work?
Optical filters selectively transmit light in a particular range of wavelengths, that is, colours, while absorbing the remainder. They can usually pass long wavelengths only (longpass), short wavelengths only (shortpass), or a band of wavelengths, blocking both longer and shorter wavelengths (bandpass).
What are the two types of optical filters?
Optical filters are passive devices that allow the transmission of a specific wavelength or set of wavelengths of light. There are two classes of optical filters that have different mechanisms of operation: absorptive filters and dichroic filters.
Can we use grating as optical filter?
Diffraction gratings are desirable as narrow-band filters because they are highly dispersive. A grating, if used properly, has a dλ/dθ that may be an order of magnitude larger than that of a typical prism. Also, since they are reflective, it is possible to use gratings far into the UV.
What is the purpose of an optical filter?
An optical filter is used to “attenuate or enhance an image.” An optical filter can also reflect unique wavelengths, split images into two identical images or transmit an image.
What are the different types of filters?
Filters can be active or passive, and the four main types of filters are low-pass, high-pass, band-pass, and notch/band-reject (though there are also all-pass filters).
Does a filter reflect light?
In any filter, a small amount of the incident light is reflected from the surface regardless of the filter construction and a small portion of the light is also absorbed. However, these artifacts are usually very minimal and do not interfere with the primary function of the filter.
What are optical filters made of?
There are two general categories of optical filters: absorptive and dichroic (also called interference) filters. Absorptive filters tend to be made from glass with selected organic or inorganic compounds added.
How does a dichroic filter work?
Dichroic filters use the principle of thin-film interference, and produce colors in the same way as oil films on water. When light strikes an oil film at an angle, some of the light is reflected from the top surface of the oil, and some is reflected from the bottom surface where it is in contact with the water.
Why do we use filter in spectrophotometer?
The filter selects the transmitted wavelength range through an absorption or interference process.
How do you make an optical filter?
For optical filters with multiple layers, the thickness of each layer is chosen so that the reflections of a selected wavelength either interfere constructively or destructively with themselves. A quarter-wave layer (QWL) is designed to reflect a certain wavelength of light and is commonly used in optical filters.