The invention discloses a
chirp spectral pattern cavity-less
optical fiber Fabry-Perot filter. The filter is characterized in that the filter comprises a multi-mode micro-nano
optical fiber cladding,a multi-mode micro-nano
optical fiber core and a Bragg
grating; the multi-mode micro-nano optical
fiber cladding is an outermost layer. According to the along-axis cross section of the multi-mode micro-nano optical
fiber cladding, transition is realized from a uniform region with a constant
radius to a micro-nano region with a gradually-changed
radius, and again transition is realized from the micro-nano region with the gradually-changed
radius to the other uniform region with a constant radius. The multi-mode micro-nano optical
fiber core is an inner layer and is covered by the multi-mode micro-nano optical fiber cladding. According to the along-axis cross section of the multi-mode micro-nano optical fiber core, transition is realized from a uniform region with a constant radius to a micro-nano region with a gradually-changed radius, and again transition is realized from the micro-nano region with the gradually-changed radius to the other uniform region with a constant radius. The Bragg
grating is a continuously-inscribed and equal-period Bragg
grating which covers all the micro-nano region of the multi-mode micro-nano optical fiber core. With the
chirp spectral pattern cavity-less optical fiber Fabry-Perot filter provided by the invention adopted, a
chirp spectral pattern which can change in a
free spectral range can be realized within a relatively large
wavelength range, anda relatively large
chirp rate can be realized. The chirp spectral pattern cavity-less optical fiber Fabry-Perot filter has the advantages of compact structure and easiness in manufacture.