Fiber bandpass filters are the optical filters that allow optical signals of certain frequencies to pass through while blocking the optical signals of other frequencies. To block the light of unwanted frequencies, they either absorb the light or reflect it or do both. You can use a band-pass filter to transmit signals in a specific range of frequencies, varying from a narrow band to a wide range.
An Overview of a Band-Pass Filter
Optical bandpass filters are micro-optics devices that transmit (or pass) a specific range (or band) of frequencies and block others. This specific range can include visible light, as well as non-visible wavelengths that fall at the infrared and ultraviolet ends of the spectrum.
Since the filter passes only a certain band of frequencies, the result is an output that comprises only light signals with desired frequencies and wavelengths.
You can define them through various characteristics, including:
- Blocking level – how effectively and efficiently the bandpass filter is able to eliminate the unwanted wavelengths
- Peak Transmission – how effectively the incident light is propagated and transmitted
- Central Wavelength – the wavelength of the light at the center of the transmission band profile
- Full Width at Half Maximum – the limits of bandwidth between which 50 percent or more light is transmitted
For instance, a very high transmission across the FWHM range with a very low transmission outside of that range is an indication that a bandpass filter is highly effective and has very little noise in the output.
What is a band-pass filter used for?
A fiber bandpass filter is used for blocking unwanted noise signals in a wide range of systems and applications, such as:
- Fiber amplifiers
- Fiber lasers systems
- EDFA systems
- DWDM systems
- High-speed communication system
- Instrumentation applications
Apart from this, optical bandpass filters are also used for anti-reflection and anti-glare coatings, chemical analysis, dielectric mirrors, high reflectors, IR applications, fluorescence filters, long-wave pass, shortwave pass, UV applications, and more.
Generally, bandpass filters are made in two ways. Thin-film filters and coated filters are designed through the deposition of multilayer dielectric coatings onto a substrate. On the other hand, spectral and absorption filters are made by a combination of lamination, cemented layers, and thin film coating.
Fiber bandpass filters are designed based on environmentally stable thin-film filter technology. They work by absorbing or reflecting unwanted wavelengths and transmitting only desirable parts of the light spectrum.
By combing filters and different methods, it is possible to design single laminated bandpass filters with very specific and complex properties to meet the needs of all kinds of electro-optical applications.
DK Photonics is an esteemed optical passive component manufacturer based in China, offering a wide range of fiber optics passive components, including fiber bandpass filters characterized by high isolation, low insertion loss, high extinction ratio, and excellent stability. To buy fiber bandpass filters with standard or customized specifications, please get in touch with us.