Integrated optical temporal Fourier transformer based on a chirped Bragg grating waveguide

Abstract

We experimentally demonstrate the first integrated temporal Fourier transformer based on a linearly chirped Bragg grating waveguide written in silica glass with a femtosecond laser. The operation is based on mapping the energy spectrum of the input optical signal to the output temporal waveform by making use of first-order chromatic dispersion. The device operates in reflection, has a bandwidth of 10 nm, and can be used for incident temporal waveforms as long as 20 ps. Experimental results, obtained through both temporal oscilloscope traces and Fourier transform spectral interferometry, display a successful Fourier transformation of in-phase and out-of-phase pairs of input optical pulses, and demonstrate the correct functionality of the device for both amplitude and phase of the temporal output.

Fabricating waveguide Bragg gratings (WBGs) in bulk materials using ultrashort laser pulses

“…For comparison, Table 1 lists κ values for The duty cycle was fixed at 35%, whereas the writing pulse energy was varied. [21] PbP 1551 25 -Boro-aluminosilicate (Eagle2000) [22] PbP 1551 145 0.6 Boro-aluminosilicate (Eagle2000) [23] PbP 1550 472 0.5 Soda-lime [27] Two-step PbP 1577 14 -Fused silica [26] Modulated burst 1548 111 1.5 Er:Yb codoped phosphate [30] Modulated burst 1537 242 -Yb-doped phosphate [42] Modulated burst 1535 221 -Boro-aluminosilicate (Eagle2000) [31] Modulated burst 1551 713 -Fused silica [43] Modulated burst 1546 36 0.7 Boro-aluminosilicate (Eagle2000) [24] PbP 799 65 -Boro-aluminosilicate (Eagle2000) [28] Modulated burst 1552 157 -ZBLAN [29] PbP überstructure 1550 324 -Boro-aluminosilicate (Eagle2000) [44] Multiscan modulated burst 1563 177 -LiNbO 3 [45] Modulated burst stressors 1540 45 -Boro-aluminosilicate (Eagle2000) [41] PbP 648 136 -Boro-aluminosilicate (Eagle2000) [41] PbP 698 183 0.8 Boro-aluminosilicate (Eagle2000) [41] PbP 748 187 -Boro-aluminosilicate (Eagle2000) [41] PbP 798 163 -Fused silica [46] Modulated burst 1550 210 2.2 Fused silica [47] Modulated burst 1549 280 < 1 Chalcogenide (GLS) [48] Modulated burst 1551 179 -LiNbO 3 [49] Multiscan modulated burst (depressed clad) 1558 1230 1.52-3.51 Boro-aluminosilicate (Eagle2000) [50] Two-step PbP 1545 120 -Fused silica [25] PbP (waveguide bundle) 840 126 -Fused silica [25] PbP (waveguide bundle) 1550 220 1.6 Borosilicate (AF45) [51] Modulated …”

“…This approach was taken by Dolgaleva et al who used a linearly chirped grating to take the temporal Fourier transform of an incident optical pulse [43]. A chirped WBG can perform a temporal Fourier transform of an optical signal if it has a sufficient amount of dispersion.…”

Self-adaptive noise suppression for characterizing the dispersion of chirped fiber Bragg grating

“…However, the first prerequisite is to characterize the dispersion property of the CFBG itself. General approaches for characterizing the dispersion property of CFBG include the pulse scanning method, modulation phase shift method, high-coherence interferometry, and low-coherence interferometry (LCI) [7][8][9][10][11]. Although each of these methods is feasible, LCI increasingly attracts the attention of researchers because of its advantages of high speed, high precision, simple configuration, and low cost.…”

Femtosecond laser fabrication of phase-shifted Bragg grating waveguides in fused silica

“…The present technique of controlling the phase, amplitude, and duty cycle of the laser burst trains will further enable apodized and chirped BGWs to be formed and the possibility for arbitrary tailoring of Bragg grating spectral shapes for pulse shaping [18]. These advantages can now be exploited for devices formed in bulk optics, extending beyond the limits of present-day fiber grating devices.…”