Real-time optical spectrum analysis based on the time-space duality in chirped fiber gratings

Based on time-space duality, we deduce a time-domain equivalent to the Fraunhofer (far-field) approximation in the problem of spatial diffraction. We can use this equivalence to carry out a real-time optical spectrum analysis, which is shown to be realizable by using, as the dispersive media, filtering devices based on chirped distributed resonant coupling. In particular, we present the design of linearly chirped fiber gratings (reflection configurations) and linearly chirped intermodal couplers (transmission configurations) to work as real-time spectrum analyzers. The proposed systems are shown to work properly by means of simulation tools. Furthermore, we use joint time-frequency signal representations to get a better understanding of the physical processes that determine the behavior of these systems. In this way, we demonstrate that the propagation of a given signal through a chirped fiber grating (or a chirped intermodal coupler), under the temporal Fraunhofer conditions, translates into a temporal separation of the spectral components of the signal. The results of our study indicate potential important applications based on this effect.

[1]  E. Treacy.  Optical pulse compression with diffraction gratings , 1969 .

[2]  T. Jannson,et al.  Temporal self-imaging effect in single-mode fibers , 1981 .

[3]  Collett-Wolf equivalence theorem and propagation of a pulse in a single-mode optical fiber. , 1982, Optics letters.

[4]  T Jannson,et al.  Real-time Fourier transformation in dispersive optical fibers. , 1983, Optics letters.

[5]  J. Kuhl,et al.  Compression of femtosecond optical pulses with dielectric multilayer interferometers , 1986 .

[6]  F. Ouellette.  Dispersion cancellation using linearly chirped Bragg grating filters in optical waveguides. , 1987, Optics letters.

[7]  Oscar E. Martínez,et al.  3000 times grating compressor with positive group velocity dispersion: Application to fiber compensation in 1.3-1.6 µm region , 1987 .

[8]  Moshe Nazarathy,et al.  Temporal imaging with a time lens: erratum , 1990 .

[9]  B H Kolner,et al.  Temporal imaging with a time lens. , 1990, Optics letters.

[10]  F Ouellette,et al.  All-fiber filter for efficient dispersion compensation. , 1991, Optics letters.

[11]  A. Lohmann,et al.  Temporal filtering with time lenses. , 1992, Applied optics.

[12]  Applications of Time-Lens Optical Systems , 1993 .

[13]  A. Papoulis.  PULSE COMPRESSION, FIBER COMMUNICATIONS, AND DIFFRACTION : A UNIFIED APPROACH , 1994 .

[14]  R. Scott,et al.  Temporal magnification and reversal of 100 Gb/s optical data with an up‐conversion time microscope , 1994 .

[15]  F. Ouellette,et al.  All-fiber devices for chromatic dispersion compensation based on chirped distributed resonant coupling , 1994 .

[16]  B. Kolner.  Space-time duality and the theory of temporal imaging , 1994 .

[17]  Michalis N. Zervas,et al.  Effects of non-ideal group delay and reflection characteristics of chirped fibre grating dispersion compensators , 1997 .

[18]  D. B. Patterson,et al.  Fiber Bragg gratings for dispersion compensation in transmission: theoretical model and design criteria for nearly ideal pulse recompression , 1997 .

[19]  John E. Sipe,et al.  Applications of ultrashort pulse propagation in Bragg gratings for wavelength-division multiplexing and code-division multiple access , 1998 .

[20]  K. Ennser,et al.  Optimization of apodized linearly chirped fiber gratings for optical communications , 1998 .

[21]  M A Muriel,et al.  Real-time Fourier transformer based on fiber gratings. , 1999, Optics letters.

[22]  José Azaña,et al.  Experimental demonstration of real-time Fourier transformation using linearly chirped fibre Bragg gratings , 1999 .

[23]  José Azaña,et al.  Field distributions inside fiber gratings , 1999 .

[24]  M A Muriel,et al.  Temporal Talbot effect in fiber gratings and its applications. , 1999, Applied optics.

[25]  J. Azaña,et al.  Technique for multiplying the repetition rates of periodic trains of pulses by means of a temporal self-imaging effect in chirped fiber gratings. , 1999, Optics letters.