High efficiency in-fiber bandpass filters with arbitrary passband/stop-band combinations have been produced successfully with an UV postfabrication exposure technique in broadly chirped fiber gratings. By further concatenating such a bandpass filter with two additional chirped gratings we achieved a finesse as high as 220 for a 36-nm stop band. This new approach exhibits great advantages in controlling precisely the profiles of bandpass filters in terms of stop-band width, transmission wavelength and linewidth, and spacing of passbands.
© 1995 Optical Society of America
L. Zhang, K. Sugden, J. A. R. Williams, I. Bennion, D. C. J. Reid, and C. M. Ragdale, "Postfabrication exposure of gap-type bandpass filters in broadly chirped fiber gratings," Opt. Lett. 20, 1927-1929 (1995)