Free spectral range variations of grating-based Fabry–Perot filters photowritten in optical fibers

We fabricated grating-based Fabry–Perot (FP) interferometers by photowriting a pair of Bragg gratings with a spacing of a few millimeters in a germanosilicate fiber. The measured free spectral range (FSR) of the FP filters is found to vary with the frequency in the spectral range of the filters. Relative FSR variation reaches values close to 10%. An analytical model is presented and compared with a coupled-mode theory in a matrix approach. The computations and the experimental results demonstrate that the main FSR variation (10%) is due to the spectral modification of the reflection coefficients of the two gratings. The relative FSR variation that is due to the propagation effective-index modification is found to be close to 10−5. A comparison between a grating-based FP filter photowritten in a fiber and a bulk FP filter is presented.

[1]  K. Hill,et al.  Aperiodic distributed-parameter waveguides for integrated optics. , 1974, Applied optics.

[2]  Gerald Meltz,et al.  Fiber Fabry-Perot interferometer using side exposed fiber Bragg gratings , 1992 .

[3]  Dana Z. Anderson,et al.  Production of in-fibre gratings using a diffractive optical element , 1993 .

[4]  Elsa Garmire,et al.  Comparison between the matrix method and the coupled-wave method in the analysis of Bragg reflector structures , 1992 .

[5]  T. Erdogan,et al.  Four channel fibre grating demultiplexer , 1994 .

[6]  G. Meltz,et al.  Formation of Bragg gratings in optical fibers by a transverse holographic method. , 1989, Optics letters.

[7]  Steven T. Davey,et al.  All-fibre narrowband reflection gratings at 1500 nm , 1990 .

[8]  Optical bistability in an NLDFB device showing absorption: comparison of feedback efficiencies for different grating profiles and study of the behavior of aperiodic and nonperfect grating profiles , 1990 .

[9]  John E. Sipe,et al.  Optical properties of photosensitive fiber phase gratings , 1993 .

[10]  J. Bokor,et al.  Bragg gratings fabricated in monomode photosensitive optical fiber by UV exposure through a phase mask , 1993 .

[11]  Raymond M. Measures.  Fiber optic sensor considerations and developments for smart structures , 1991, Other Conferences.

[12]  A. Yariv.  Coupled-mode theory for guided-wave optics , 1973 .

[13]  William W. Morey,et al.  Bragg-Grating Temperature and Strain Sensors , 1989 .

[14]  J Chen,et al.  Cross talk of Fabry - Perot filters and its effect on the performance of optical fiber frequency-division-multiplexing/frequency-shift-keying systems. , 1993, Optics letters.

[15]  M. Yamada,et al.  Analysis of almost-periodic distributed feedback slab waveguides via a fundamental matrix approach. , 1987, Applied optics.

[16]  Marc Douay,et al.  Second order diffraction efficiency of Bragg gratings written within germanosilicate fibres , 1993 .

[17]  D. K. Lam,et al.  Characterization of single-mode optical fiber filters. , 1981, Applied optics.

[18]  Bertrand Poumellec,et al.  Experimental evidence of two types of photorefractive effects occuring during photoinscriptions of Bragg gratings within germanosilicate fibres , 1993 .

[19]  K. Hill,et al.  Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication , 1978 .

[20]  M. A. Putnam,et al.  Fiber Bragg reflectors prepared by a single excimer pulse. , 1992, Optics letters.

[21]  Laurence Reekie,et al.  High reflectivity ad narrow bandwidth fibre gratings written by single excimer pulse , 1993 .

[22]  William W. Morey,et al.  Nd3+ fibre laser utilising intra-core Bragg reflectors , 1990 .

[23]  R. K. Froelich,et al.  Fundamental high-frequency performance limit for IMPATT mode operation , 1985 .

[24]  H. Kogelnik,et al.  Filter response of nonuniform almost-periodic structures , 1976, The Bell System Technical Journal.