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Journal ArticleDOI

Integrated Optical Rectangular-Edge Filter Devices in SOI

15 Jan 2017-Journal of Lightwave Technology (IEEE)-Vol. 35, Iss: 2, pp 128-135
TL;DR: In this paper, an integrated optical design of a rectangular-edge filter device in 250-nm silicon-on-insulator platform is proposed and demonstrated experimentally, where the device is designed with a multimode waveguide with asymmetric side-wall grating, which is adiabatically interfaced with input/output single-mode waveguides.
Abstract: An integrated optical design of a rectangular-edge filter device in 250-nm silicon-on-insulator platform is proposed and demonstrated experimentally. The device is designed with a multimode waveguide (supporting at least two modes) with asymmetric side-wall grating, which is adiabatically interfaced with input/output single-mode waveguides. The input/output access waveguides are terminated with grating couplers for optical characterizations. Design parameters are optimized for a sharp-edge or nearly rectangular-edge filter response in optical C-band (1530 nm $\leq \lambda _{\text{edge}} \leq $ 1565 nm). The submicron features and the entire footprint of the devices were defined with a single-step e-beam lithography process by using negative-tone resist and subsequent dry etching of $\sim$ 100 nm by using an inductively coupled reactive ion etching system. All the fabricated devices exhibit a rectangular-edge filter response at $\lambda _{\text{edge}} \sim $ 1560 nm with an edge-extinction of $>$ 40 dB at the rate of 118 dB/nm. The rectangular-edge is followed by a broad pass-band of $\sim $ 40 nm till the first-order Bragg reflected wavelength of $\lambda _B^{00} \sim $ 1600 nm in the transmission characteristics obtained for 1520 nm $\leq \lambda \leq$ 1620 nm. Tunability of a rectangular-edge filter is verified with cladding refractive index change and the observed refractive index sensitivity of the edge is $\sim$ 18 nm/RIU. The limit of detection for 1-dB transmitted power extinction at $\lambda _{\text{edge}}$ of a typical fabricated device is estimated to be 5.3 $\times\, \text{10}^{-4}$ RIU.
Citations
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Journal ArticleDOI
TL;DR: The achieved functional characteristics of the proposed accelerometer are compared to several recent contributions in the related field and can be a suitable device for many applications ranging from consumer electronics to inertial measurement units.
Abstract: Here, a novel optical micro-electro-mechanical systems (MEMS) accelerometer sensor based on a micro-ring resonator and an elliptical disk is proposed. The designed optical MEMS accelerometer is then analysed to obtain its functional characteristics. The proposed optical MEMS sensor presents an optical sensitivity of 0.0025 nm/g, a mechanical sensitivity of 1.56 nm/g, a linear measurement range of ±22 g, a first resonance frequency of 13.02 kHz, and a footprint of 34 μm × 50 μm. Furthermore, the achieved functional characteristics of the proposed accelerometer are compared to several recent contributions in the related field. According to this comparison study, the present optical MEMS accelerometer can be a suitable device for many applications ranging from consumer electronics to inertial measurement units.

14 citations

Journal ArticleDOI
TL;DR: In this paper, a silicon-based compact comb-like asymmetric grating is proposed as a thermally stable optical filter for label-free sensing applications, which allows a single narrow passband transmission peak with a large Free Spectral Range (FSR) attributed to the engineered photonic bandgap of two modes present in the waveguide region.
Abstract: A silicon-based compact comb-like asymmetric grating is proposed as a thermally stable optical filter for label-free sensing applications. The device is designed and fabricated with a cavity section introduced between the two grating regions which are partially etched in the lateral direction to ensure the nonzero coupling of the fundamental and first-order modes in the propagation and counter-propagation direction. To demonstrate refractive index sensing, resonance shift in the device is measured with sodium chloride (NaCl) dissolved in DI water. In contrast to conventional Bragg grating where stopband lies in the transmission spectrum, the proposed device allows a single narrow passband transmission peak with a large Free Spectral Range (FSR) attributed to the engineered photonic bandgap of two modes present in the waveguide region. The device is deliberately designed such that slightly wide resonance peak is obtained that makes device operation thermally stable for a large temperature variation of ±15 K. A higher-order leaky mode with strong light-analyte interaction (due to long corrugation width) in the gratings governs high sensitivity of ≈352 nm/RIU for different concentrations of NaCl from 0% to 10% in the Deionized (DI) water with a small footprint area of $18~{\mu } {m}^{\textsf {2}}$ only. Proposed filter characteristics are well suited for multifunctional applications in integrated photonic devices.

11 citations


Cites background from "Integrated Optical Rectangular-Edge..."

  • ...However, such devices still suffer from the narrow FSR issues which limit the sensing capability to detect a variety of material on a single device [24], [36], [37]....

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  • ..., Micro Ring Resonator (MRR) [19]–[21], Interferometry type structure [22], Sub-Wavelength Grating (SWG) based structure [23], [24] and photonic crystalbased sensors [25]....

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Journal ArticleDOI
01 Feb 2021-Optik
TL;DR: In this paper, a grating-based narrowband wavelength selective reflector on silicon on insulator waveguide is proposed, which consists of dual-etch layers for different grating sets separated by the center cavity.

8 citations

Journal ArticleDOI
TL;DR: In this paper, experimental and simulation results of sidewall Bragg gratings (BGs) implemented on a silicon nitride waveguide platform, with emphasis on the appreciable drop of transmission on the high-frequency side of the grating stopband due to the coupling into backward cladding/radiative modes.
Abstract: We present experimental and simulation results of sidewall Bragg gratings (BGs) implemented on a silicon nitride waveguide platform, with emphasis on the appreciable drop of transmission on the high-frequency side of the grating stopband due to the coupling into backward cladding/radiative modes. We differentiate this from the coupling into backward slab modes as observed in BGs implemented in silicon-on-insulator ridge waveguides. The dimension of the device top cladding affects the shape of the drop pattern. Different approaches for circumventing this drop pattern are discussed. A better understanding of this physical phenomenon will help guide the design of BGs on integrated photonic platforms.

6 citations

Journal ArticleDOI
TL;DR: In this article, an integrated optical apodized subwavelength grating waveguide is designed and demonstrated exhibiting high-extinction edge-filter characteristics with a linear rolloff in the dB scale.
Abstract: An integrated optical apodized sub-wavelength grating waveguide is designed and demonstrated exhibiting high-extinction edge-filter characteristics with a linear roll-off in the dB scale. For a given waveguide cross-sectional geometry with fixed grating duty cycle and period, it has been shown that the apodized device length $L_{g}$ and width $W_{m}$ are the two important parameters deciding the band-edge position, roll-off and broadband extinction around the Bragg wavelength. The experimental results from fabricated devices ( $L_{g} = 70\,\,\mu \text{m}$ and $W_{m} = 2.5\,\,\mu \text{m}$ ) in silicon-on-insulator substrates (device layer ~ 220 nm and buried oxide layer $\sim ~2~\mu \text{m}$ ) show a smooth band-edge roll-off of > 3.5 dB/nm ( $\lambda _{edge} \sim ~1550$ nm) with a stopband ( $\Delta \lambda _{sb}>50$ nm) extinction of > 40 dB and a nearly flat-top passband ( $\Delta \lambda _{pb}>100$ nm) with negligible insertion loss of ~ 0.5 dB.

6 citations


Cites background or methods from "Integrated Optical Rectangular-Edge..."

  • ...A recent demonstration of a rectangular edge filter using a multi-moded asymmetric side-wall grating reported an edge-extinction of > 40 dB at the rate of 118 dB/nm [10]....

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  • ...The calculated effective index ne f f (zi , λ) and locally normalized mode field distribution E(x, y, zi , λ) of the i th cell are then used to evaluate the backward coupling coefficient κ(zi , λ) for the guided fundamental mode as given by [10]:...

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References
More filters
Journal ArticleDOI
TL;DR: The techniques that have, and will, be used to implement silicon optical modulators, as well as the outlook for these devices, and the candidate solutions of the future are discussed.
Abstract: Optical technology is poised to revolutionize short-reach interconnects. The leading candidate technology is silicon photonics, and the workhorse of such an interconnect is the optical modulator. Modulators have been improved dramatically in recent years, with a notable increase in bandwidth from the megahertz to the multigigahertz regime in just over half a decade. However, the demands of optical interconnects are significant, and many questions remain unanswered as to whether silicon can meet the required performance metrics. Minimizing metrics such as the device footprint and energy requirement per bit, while also maximizing bandwidth and modulation depth, is non-trivial. All of this must be achieved within an acceptable thermal tolerance and optical spectral width using CMOS-compatible fabrication processes. This Review discusses the techniques that have been (and will continue to be) used to implement silicon optical modulators, as well as providing an outlook for these devices and the candidate solutions of the future.

2,110 citations


"Integrated Optical Rectangular-Edge..." refers methods in this paper

  • ...Such integrated optical REF devices exhibiting well-defined wavelength edge (λedge) will be useful to design compact silicon modulator with similar working principle as ring-resonator based intensity modulators [13] and/or as electro-absorption modulator [14] in ON-OFF configuration but with a very high...

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Journal ArticleDOI
TL;DR: In this article, the authors provide an overview and outlook for the silicon waveguide platform, optical sources, optical modulators, photodetectors, integration approaches, packaging, applications of silicon photonics and approaches required to satisfy applications at mid-infrared wavelengths.
Abstract: Silicon photonics research can be dated back to the 1980s. However, the previous decade has witnessed an explosive growth in the field. Silicon photonics is a disruptive technology that is poised to revolutionize a number of application areas, for example, data centers, high-performance computing and sensing. The key driving force behind silicon photonics is the ability to use CMOS-like fabrication resulting in high-volume production at low cost. This is a key enabling factor for bringing photonics to a range of technology areas where the costs of implementation using traditional photonic elements such as those used for the telecommunications industry would be prohibitive. Silicon does however have a number of shortcomings as a photonic material. In its basic form it is not an ideal material in which to produce light sources, optical modulators or photodetectors for example. A wealth of research effort from both academia and industry in recent years has fueled the demonstration of multiple solutions to these and other problems, and as time progresses new approaches are increasingly being conceived. It is clear that silicon photonics has a bright future. However, with a growing number of approaches available, what will the silicon photonic integrated circuit of the future look like? This roadmap on silicon photonics delves into the different technology and application areas of the field giving an insight into the state-of-the-art as well as current and future challenges faced by researchers worldwide. Contributions authored by experts from both industry and academia provide an overview and outlook for the silicon waveguide platform, optical sources, optical modulators, photodetectors, integration approaches, packaging, applications of silicon photonics and approaches required to satisfy applications at mid-infrared wavelengths. Advances in science and technology required to meet challenges faced by the field in each of these areas are also addressed together with predictions of where the field is destined to reach.

939 citations


"Integrated Optical Rectangular-Edge..." refers background in this paper

  • ...munities to integrate efficient light sources, modulators, photodetectors, and many other active/passive waveguide devices [2], [3]....

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Journal ArticleDOI
TL;DR: A high-efficiency broadband grating coupler for coupling between silicon-on-insulator (SOI) waveguides and optical fibers and the size of the grooves is optimized numerically.
Abstract: We have designed a high-efficiency broadband grating coupler for coupling between silicon-on-insulator (SOI) waveguides and optical fibers. The grating is only 13 µm long and 12 µm wide, and the size of the grooves is optimized numerically. For TE polarization the coupling loss to single-mode fiber is below 1 dB over a 35-nm wavelength range when using SOI with a two-pair bottom reflector. The tolerances to fabrication errors are also calculated.

676 citations


"Integrated Optical Rectangular-Edge..." refers background in this paper

  • ...grating coupler [7], narrow line-width DBR filters [8], [9], highQ Fabry-Perot resonator [10], DBR laser [11], compact modulator [12], etc....

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Journal ArticleDOI
TL;DR: In this paper, several photonic signal processors, including high-resolution microwave filters, widely tunable filters, arbitrary waveform generators, and fast signal correlators, are discussed, and a new concept for realizing multiple-tap coherence-free processor filters, based on a new frequencyshifting technique, is presented.
Abstract: Photonic signal processing offers the prospect of realizing extremely high multigigahertz sampling frequencies, overcoming inherent electronic limitations. This stems from the intrinsic excellent delay properties of optical delay lines. These processors provide new capabilities for realizing high time-bandwidth operation and high-resolution performance. In-fiber signal processors are inherently compatible with fiber-optic microwave systems and can provide connectivity with built-in signal conditioning. Fundamental principles of photonic signal processing, including sampling, tuning, and noise, are discussed. Structures that can extend the performance of photonic signal processors are presented, including methods for improving the filter shape characteristics of interference mitigation filters, techniques to increase the stopband attenuation of bandpass filters, and methods to achieve large free spectral range. Several photonic signal processors, including high-resolution microwave filters, widely tunable filters, arbitrary waveform generators, and fast signal correlators, are discussed. Techniques to solve the fundamental noise problem in photonic signal processors are described, and coherence-free structures for few-tap notch filters are discussed. Finally, a new concept for realizing multiple-tap coherence-free processor filters, based on a new frequency-shifting technique, is presented. The structure not only eliminates the phase-induced intensity noise limitation, but can also generate a large number of taps to enable the achievement of processors with high performance and high resolution.

639 citations

Journal ArticleDOI
TL;DR: In this paper, a triangular array of silicon nanostructures is experimentally demonstrated to function as an optical cloaking device, operating in the near-infrared at a wavelength of 1550-nm.
Abstract: The ability to render objects invisible using a cloak (such that they are not detectable by an external observer) has long been a tantalizing goal1,2,3,4,5,6. Here, we demonstrate a cloak operating in the near infrared at a wavelength of 1,550 nm. The cloak conceals a deformation on a flat reflecting surface, under which an object can be hidden. The device has an area of 225 µm2 and hides a region of 1.6 µm2. It is composed of nanometre-size silicon structures with spatially varying densities across the cloak. The density variation is defined using transformation optics to define the effective index distribution of the cloak. A triangular array of silicon nanostructures is experimentally demonstrated to function as an optical cloaking device, operating in the near-infrared at a wavelength of 1550 nm. This approach could, in principle, be extended to larger areas using fabrication techniques such as nanoimprinting.

631 citations


"Integrated Optical Rectangular-Edge..." refers background in this paper

  • ...dent characteristics, the SOI waveguide with sub-wavelength grating finds versatile applications like optical cloaking [4], refractive index and dispersion engineering [5], [6], broad-band...

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