Photonic temporal integrator for all-optical computing

Abstract

We report the first experimental realization of an all-optical temporal integrator. The integrator is implemented using an all-fiber active (gain-assisted) filter based on superimposed fiber Bragg gratings made in an Er-Yb co-doped optical fiber that behaves like an 'optical capacitor'. Functionality of this device was tested by integrating different optical pulses, with time duration down to 60 ps, and by integration of two consecutive pulses that had different relative phases, separated by up to 1 ns. The potential of the developed device for implementing all-optical computing systems for solving ordinary differential equations was also experimentally tested.

Photonic arbitrary waveform generator based on Taylor synthesis method

“…In previous works, arbitrary waveforms were mostly obtained by using Fourier expansion method [2,[6][7][8][9][10][11][12][13][14][15][16][17]. However, an arbitrary waveform can also be expanded by Taylor series [24] with…”

“…The schemes based on Fourier synthesis method usually consist of a source of optical frequency comb, spectral dispersers with high resolution and complex amplitude and phase modulation arrays. These schemes have very good performance and have been realized by different materials, such as mature fiber grating techniques [2,6-8], indium phosphide (InP) platform [9], silica on silicon [10,11], silicon nitride [12,13] and silicon platform [14][15][16]. However, high resolution integrated spectral disperser is still a big challenge for the chip fabrication resulting in the difficulty to manipulate the comb lines one by one when the comb spacing is very small.…”

All-optical 1st and 2nd order integration on a chip

“…K = 0) must be met, which can be achieved in one of two ways: i) compensating both propagation and coupling losses by using an active device with gain (γ>1; r<1; r 2 γ≈1) or ii) using an ultra low-loss material platform (γ≈1) which is also mature enough to allow for a very high mirror reflectivity (r≈1). However, the first strategy implies the use of gain in the cavity and this introduces other limitations such as limited processing speed <20GHz as well as increased signal to noise ratio, in addition to adding fabrication steps that may not be CMOS compatible [12,15]. On the other hand, typical passive photonic integrators such as those based on fiber Bragg gratings (FBG), either suffer from a very limited integration time window [16,17] or require a reflectivity approaching 100% [18], which is quite a stringent requirement.…”

“…The realization of an optical integrator in integrated, or monolithic, form would represent a fundamental step for many ultra-fast data processing applications, including photonic bit counting [7], pulse waveform shaping [1, [7][8], data storage [9,10], analog-to-digital conversion [11], and real time computation of linear differential equations [12]. For many of these applications, and particularly the latter, the ability to perform optical integration even just up to second order would be extremely useful.…”

All-optical flip-flops based on dynamic Brillouin gratings in fibers

“…Approaches using a resonator [6] and fiber Bragg gratings (FBGs) [7][8][9] have been reported in the literature. Hybrid (active-passive) approaches incorporating Bragg gratings and active fiber have also been validated [10].…”