Distributed Bragg Reflector Filter
Application ID: 22561
A distributed Bragg reflector (DBR) is a periodic structure formed from alternating dielectric layers that can be used to achieve nearly total reflection within a range of frequencies. The main advantage of DBRs over ordinary metallic mirrors is that DBRs can be engineered to have custom reflectances at selected wavelengths.
This application allows the performance of two different kinds of DBR filters to be simulated and characterized: Band-stop filters and Notch filters.
A band-stop filter prevents wavelengths within the range of the stop-band from transmitting. This is useful for filtering out unwanted wavelength regions from a spectrum. Band-stop filters are commonly included in many kinds of optical measurement setups, where they are used to prevent stray laser light from entering the sensitive detector equipment.
A notch filter allows a narrow range of wavelengths to pass while reflecting all other wavelengths. This is useful for selecting emission from a spectrally narrow source, such as individual transitions in a gas, while rejecting optical contamination from other emission sources.
The inputs to this application configure the properties of the geometry and the layer refractive indices.Results are presented as plots of the reflectance over a range of radiation wavelengths. The width of the stop-band is presented for both filter cases, while the reflectance of the notch and the width of the notch pass-band is also calculated.
This model example illustrates applications of this type that would nominally be built using the following products:
however, additional products may be required to completely define and model it. Furthermore, this example may also be defined and modeled using components from the following product combinations:
The combination of COMSOL® products required to model your application depends on several factors and may include boundary conditions, material properties, physics interfaces, and part libraries. Particular functionality may be common to several products. To determine the right combination of products for your modeling needs, review the Specification Chart and make use of a free evaluation license. The COMSOL Sales and Support teams are available for answering any questions you may have regarding this.