Page 323 - Fiber Bragg Gratings

300 Chapter 6 Fiber Grating Band-pass Filters

gratings between 27 and 35 mm long have been fabricated with periods
ranging from 116 to 135 /urn in few-moded fiber. Up to 85% coupling is
obtained with a FWHM bandwidth of 25 nm. The step-chirped technique
[120] can also be used to broaden the bandwidth for longer mode-converter
gratings. A 65-mm-long grating with a 0.3-yitm chirp over four sections
has been demonstrated to have a peak coupling efficiency of 90% at 1556
nm and a FWHM bandwidth of 14 nm.

References

1. Haus H. A. and Shank C. V., "Anti-symmetric type of distributed feedback
lasers," J. Quantum Electron 12, 532-539 (1976).
2. Utaka K., Akiba S., and Matsushima Y., "1/4-shifted GaAsP/InP DFB lasers
by simultaneous holographic exposure of negative and positive photoresists,"
Electron. Lett. 20, 1008-1010 (1984).
3. Haus H. A. and Lai Y., "Theory of cascaded quarter wave shifted distributed
feedback resonators," IEEE J. Quantum Electron. 28(1), 205-213 (1992).
4. Zengerle R. and Leminger O., "Phase-shifted Bragg-grating filters with im-
proved transmission characteristics," J. Lightwave Technol. 13(2),
2354-2358 (1995).
5. Agrawal G. P. and Radic S., "Phase-shifted fiber Bragg gratings and their
applications for wavelength demultiplexing," IEEE Photon. Technol. Lett. 6,
995-997 (1994).
6. Kashyap R., McKee P. E., and Armes D., "UV written reflection grating
structures in photosensitive optical fibres using phase-shifted phase-masks,"
Electron. Lett. 30(23), 1977-1978 (1994).
7. Canning J. and Sceats M. G., 'V-phase shifted periodic distributed structures
in optical fibers by UV post-processing," Electron. Lett. 30(16), 1244-1245
(1994).
8. Asseh H., Storoy H., Kringlebotn J. T, Margulis W., Sahlgren B., and Sand-
+
gren S., "10 cm long Yb DFB fibre laser with permanent phase shifted
grating," Electron. Lett. 31, 969-970 (1995).
9. Loh W. H. and Laming R. I., "1.55 yum phase-shifted distribute feedback fibre
laser," Electron. Lett. 31(17), 1440-1442 (1995).
10. Hiibner J., Varming P., and Kristensen M., "Five wavelength DFB fibre laser
source for WDM systems," Electron. Lett. 33(2), 139-140 (1997).
11. Zever I, Handbook of Filter Synthesis. Wiley, New York (1967).