Experimental observation of optical differentiation and optical Hilbert transformation using a single SOI microdisk chip

Abstract

Optical differentiation and optical Hilbert transformation play important roles in communications, computing, information processing and signal analysis in optical domain offering huge bandwidth. Meanwhile, silicon-based photonic integrated circuit is one of the most promising candidates for all-optical signal processing due to its intrinsic advantages of low power consumption, compact footprint, ultra-high speed and compatibility with electronic integrated circuits. In this study, we analyze the interrelation between first-order optical differentiation and optical Hilbert transformation and then experimentally demonstrate a feasible integrated scheme which can simultaneously function as first-order optical differentiation and optical Hilbert transformation based on a single microdisk resonator. This finding may motivate the development of integrated optical signal processors.

Reconfigurable broadband microwave photonic intensity differentiator based on an integrated optical frequency comb source

“…Our CMOS compatible fabrication process makes our differentiators comparable, in terms of fabrication maturity, to those implemented by means of optoelectronics silicon devices. [13][14][15][16][17] In particular, we note that, due to the ultra-low loss of our platform, the ring resonator has a quality factor of ∼1.2 × 10 6 . Our device architecture uses a vertical coupling scheme where the gap can be controlled via film growth-a more accurate approach than lithographic techniques.…”

“…(2) are intensity differentiators for baseband RF input signals, i.e., the combined output RF signal after detection yields an exact differentiation of the input RF signal, in contrast to field differentiators that yield the derivative of a complex optical field. 8,10,[12][13][14][15][16][17] We note that while optical field differentiators can be used to directly operate on microwave photonic signals, our approach has important advantages. When an RF signal is modulated onto an optical carrier, the intensity of the optical carrier is proportional to the square of the RF field.…”

“…[8][9][10] To implement photonic differentiators, a number of schemes have been proposed, which can be classified into two categories, namely, field differentiators and intensity differentiators. 11 Field differentiators based on apodized fibre Bragg gratings 8,10,12 and integrated silicon photonic devices [13][14][15][16][17] have recently been demonstrated. These types of devices yield the derivative of a complex optical field and have the ability to shape ultra-short optical pulses that could find applications in optical pulse generation and advanced coding.…”

1D Photonic Crystals: Principles and Applications in Silicon Photonics

“…Extensive research has been performed to realize large-scale integration of silicon photonics for optical communication networks [1,2], optical computing [3,4], and biosensing [5,6]. The impetus of this research lies in the fact that silicon-on-insulator (SOI) technology is fully compatible with complementary metal oxide semiconductor (CMOS) technology and possesses high refractive index contrast enabling compact devices.…”

Hilbert transform: Applications to atomic spectra

“…The basic Hilbert transform can be used to quickly convert a real function to its imaginary counterpart. Although the Hilbert transform is well known in the field of communications [17] and signal processing [15] and has been applied to group delay measurements on fiber Bragg gratings [10], it is relatively underutilized in the field of quantum and atomic optics, where measurements and predictions of the refractive index are often needed.…”