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12 pages, 4032 KiB

Open AccessArticle

Design Consideration, Numerical and Experimental Analyses of Mode-Division-Multiplexed (MDM) Silicon Photonics Integrated Circuit with Sharp Bends

by Pin-Cheng Kuo, Chi-Wai Chow, Yuan-Zeng Lin, Wahyu Hendra Gunawan, Tun-Yao Hung, Yin-He Jian, Guan-Hong Chen, Ching-Wei Peng, Yang Liu and Chien-Hung Yeh

Sensors 2023, 23(6), 2965; https://doi.org/10.3390/s23062965 - 9 Mar 2023

Cited by 2 | Viewed by 2146

Abstract

Due to the popularity of different high bandwidth applications, it is becoming increasingly difficult to satisfy the huge data capacity requirements, since the traditional electrical interconnects suffer significantly from limited bandwidth and huge power consumption. Silicon photonics (SiPh) is one of the important [...] Read more.

Due to the popularity of different high bandwidth applications, it is becoming increasingly difficult to satisfy the huge data capacity requirements, since the traditional electrical interconnects suffer significantly from limited bandwidth and huge power consumption. Silicon photonics (SiPh) is one of the important technologies for increasing interconnect capacity and decreasing power consumption. Mode-division multiplexing (MDM) allows signals to be transmitted simultaneously, at different modes, in a single waveguide. Wavelength-division multiplexing (WDM), non-orthogonal multiple access (NOMA) and orthogonal-frequency-division multiplexing (OFDM) can also be utilized to further increase the optical interconnect capacity. In SiPh integrated circuits, waveguide bends are usually inevitable. However, for an MDM system with a multimode bus waveguide, the modal fields will become asymmetric when the waveguide bend is sharp. This will introduce inter-mode coupling and inter-mode crosstalk. One simple approach to achieve sharp bends in multimode bus waveguide is to use a Euler curve. Although it has been reported in the literature that sharp bends based on a Euler curve allow high performance and low inter-mode crosstalk multimode transmissions, we discover, by simulation and experiment, that the transmission performance between two Euler bends is length dependent, particularly when the bends are sharp. We investigate the length dependency of the straight multimode bus waveguide between two Euler bends. High transmission performance can be achieved by a proper design of the waveguide length, width, and bend radius. By using the optimized MDM bus waveguide length with sharp Euler bends, proof-of-concept NOMA-OFDM experimental transmissions, supporting two MDM modes and two NOMA users, are performed. Full article

(This article belongs to the Special Issue Silicon Photonics: A Theme Issue in Honor of Professor Richard A. Soref)

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10 pages, 5444 KiB

Open AccessArticle

Wideband and Channel Switchable Mode Division Multiplexing (MDM) Optical Power Divider Supporting 7.682 Tbit/s for On-Chip Optical Interconnects

by Tun-Yao Hung, Guan-Hong Chen, Yuan-Zeng Lin, Chi-Wai Chow, Yin-He Jian, Pin-Cheng Kuo, Ching-Wei Peng, Jui-Feng Tsai, Yang Liu and Chien-Hung Yeh

Sensors 2023, 23(2), 711; https://doi.org/10.3390/s23020711 - 8 Jan 2023

Cited by 6 | Viewed by 2774

Abstract

Silicon photonics (SiPh) are considered a promising technology for increasing interconnect speed and capacity while decreasing power consumption. Mode division multiplexing (MDM) enables signals to be transmitted in different orthogonal modes in a single waveguide core. Wideband MDM components simultaneously supporting wavelength division [...] Read more.

Silicon photonics (SiPh) are considered a promising technology for increasing interconnect speed and capacity while decreasing power consumption. Mode division multiplexing (MDM) enables signals to be transmitted in different orthogonal modes in a single waveguide core. Wideband MDM components simultaneously supporting wavelength division multiplexing (WDM) and orthogonal frequency-division multiplexing (OFDM) can significantly increase the transmission capacity for optical interconnects. In this work, we propose, fabricate and demonstrate a wideband and channel switchable MDM optical power divider on an SOI platform, supporting single, dual and triple modes. The switchable MDM power divider consists of two parts. The first part is a cascaded Mach–Zehnder interferometer (MZI) for switching the data from their original TE₀, TE₁ and TE₂ modes to different modes among themselves. After the target modes are identified, mode up-conversion and Y-branch are utilized in the second part for the MDM power division. Here, 48 WDM wavelength channels carrying OFDM data are successfully switched and power divided. An aggregated capacity of 7.682 Tbit/s is achieved, satisfying the pre-forward error correction (pre-FEC) threshold (bit-error-rate, BER = 3.8 × 10⁻³). Although up to three MDM modes are presented in the proof-of-concept demonstration here, the proposed scheme can be scaled to higher order modes operation. Full article

(This article belongs to the Special Issue Silicon Photonics: A Theme Issue in Honor of Professor Richard A. Soref)

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9 pages, 3403 KiB

Open AccessCommunication

Optical Temperature Sensor Based on Polysilicon Waveguides

by Xinru Xu, Yuexin Yin, Chunlei Sun, Lan Li, Hongtao Lin, Bo Tang, Peng Zhang, Changming Chen and Daming Zhang

Sensors 2022, 22(23), 9357; https://doi.org/10.3390/s22239357 - 1 Dec 2022

Cited by 2 | Viewed by 2023

Abstract

Traditional temperature detection has limitations in terms of sensing accuracy and response time, while chip-level photoelectric sensors based on the thermo-optic effect can improve measurement sensitivity and reduce costs. This paper presents on-chip temperature sensors based on polysilicon (p-Si) waveguides. Dual-microring resonator (MRR) [...] Read more.

Traditional temperature detection has limitations in terms of sensing accuracy and response time, while chip-level photoelectric sensors based on the thermo-optic effect can improve measurement sensitivity and reduce costs. This paper presents on-chip temperature sensors based on polysilicon (p-Si) waveguides. Dual-microring resonator (MRR) and asymmetric Mach–Zehnder interferometer (AMZI) sensors are demonstrated. The experimental results show that the sensitivities of the sensors based on AMZI and MRR are 86.6 pm/K and 85.7 pm/K, respectively. The temperature sensors proposed in this paper are compatible with the complementary metal-oxide-semiconductor (CMOS) fabrication technique. Benefitting from high sensitivity and a compact footprint, these sensors show great potential in the field of photonic-electronic applications. Full article

(This article belongs to the Special Issue Silicon Photonics: A Theme Issue in Honor of Professor Richard A. Soref)

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15 pages, 4270 KiB

Open AccessArticle

Circular Optical Phased Array with Large Steering Range and High Resolution

by Daniel Benedikovič, Qiankun Liu, Alejandro Sánchez-Postigo, Ahmad Atieh, Tom Smy, Pavel Cheben and Winnie N. Ye

Sensors 2022, 22(16), 6135; https://doi.org/10.3390/s22166135 - 16 Aug 2022

Cited by 10 | Viewed by 3074

Abstract

Light detection and ranging systems based on optical phased arrays and integrated silicon photonics have sparked a surge of applications over the recent years. This includes applications in sensing, free-space communications, or autonomous vehicles, to name a few. Herein, we report a design [...] Read more.

Light detection and ranging systems based on optical phased arrays and integrated silicon photonics have sparked a surge of applications over the recent years. This includes applications in sensing, free-space communications, or autonomous vehicles, to name a few. Herein, we report a design of two-dimensional optical phased arrays, which are arranged in a grid of concentric rings. We numerically investigate two designs composed of 110 and 820 elements, respectively. Both single-wavelength (1550 nm) and broadband multi-wavelength (1535 nm to 1565 nm) operations are studied. The proposed phased arrays enable free-space beam steering, offering improved performance with narrow beam divergences of only 0.5° and 0.22° for the 110-element and 820-element arrays, respectively, with a main-to-sidelobe suppression ratio higher than 10 dB. The circular array topology also allows large element spacing far beyond the sub-wavelength-scaled limits that are present in one-dimensional linear or two-dimensional rectangular arrays. Under a single-wavelength operation, a solid-angle steering between 0.21π sr and 0.51π sr is obtained for 110- and 820-element arrays, respectively, while the beam steering spans the range of 0.24π sr and 0.57π sr for a multi-wavelength operation. This work opens new opportunities for future optical phased arrays in on-chip photonic applications, in which fast, high-resolution, and broadband beam steering is necessary. Full article

(This article belongs to the Special Issue Silicon Photonics: A Theme Issue in Honor of Professor Richard A. Soref)

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Review

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22 pages, 6749 KiB

Open AccessReview

Near-IR & Mid-IR Silicon Photonics Modulators

by Georgi V. Georgiev, Wei Cao, Weiwei Zhang, Li Ke, David J. Thomson, Graham T. Reed, Milos Nedeljkovic and Goran Z. Mashanovich

Sensors 2022, 22(24), 9620; https://doi.org/10.3390/s22249620 - 8 Dec 2022

Cited by 5 | Viewed by 4102

Abstract

As the silicon photonics field matures and a data-hungry future looms ahead, new technologies are required to keep up pace with the increase in capacity demand. In this paper, we review current developments in the near-IR and mid-IR group IV photonic modulators that [...] Read more.

As the silicon photonics field matures and a data-hungry future looms ahead, new technologies are required to keep up pace with the increase in capacity demand. In this paper, we review current developments in the near-IR and mid-IR group IV photonic modulators that show promising performance. We analyse recent trends in optical and electrical co-integration of modulators and drivers enabling modulation data rates of 112 GBaud in the near infrared. We then describe new developments in short wave infrared spectrum modulators such as employing more spectrally efficient PAM-4 coding schemes for modulations up to 40 GBaud. Finally, we review recent results at the mid infrared spectrum and application of the thermo-optic effect for modulation as well as the emergence of new platforms based on germanium to tackle the challenges of modulating light in the long wave infrared spectrum up to 10.7

μ

m with data rates of 225 MBaud. Full article

(This article belongs to the Special Issue Silicon Photonics: A Theme Issue in Honor of Professor Richard A. Soref)

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29 pages, 8159 KiB

Open AccessReview

Metasurfaces for Sensing Applications: Gas, Bio and Chemical

by Shawana Tabassum, SK Nayemuzzaman, Manish Kala, Akhilesh Kumar Mishra and Satyendra Kumar Mishra

Sensors 2022, 22(18), 6896; https://doi.org/10.3390/s22186896 - 13 Sep 2022

Cited by 39 | Viewed by 7000

Abstract

Performance of photonic devices critically depends upon their efficiency on controlling the flow of light therein. In the recent past, the implementation of plasmonics, two-dimensional (2D) materials and metamaterials for enhanced light-matter interaction (through concepts such as sub-wavelength light confinement and dynamic wavefront [...] Read more.

Performance of photonic devices critically depends upon their efficiency on controlling the flow of light therein. In the recent past, the implementation of plasmonics, two-dimensional (2D) materials and metamaterials for enhanced light-matter interaction (through concepts such as sub-wavelength light confinement and dynamic wavefront shape manipulation) led to diverse applications belonging to spectroscopy, imaging and optical sensing etc. While 2D materials such as graphene, MoS₂ etc., are still being explored in optical sensing in last few years, the application of plasmonics and metamaterials is limited owing to the involvement of noble metals having a constant electron density. The capability of competently controlling the electron density of noble metals is very limited. Further, due to absorption characteristics of metals, the plasmonic and metamaterial devices suffer from large optical loss. Hence, the photonic devices (sensors, in particular) require that an efficient dynamic control of light at nanoscale through field (electric or optical) variation using substitute low-loss materials. One such option may be plasmonic metasurfaces. Metasurfaces are arrays of optical antenna-like anisotropic structures (sub-wavelength size), which are designated to control the amplitude and phase of reflected, scattered and transmitted components of incident light radiation. The present review put forth recent development on metamaterial and metastructure-based various sensors. Full article

(This article belongs to the Special Issue Silicon Photonics: A Theme Issue in Honor of Professor Richard A. Soref)

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35 pages, 10822 KiB

Open AccessReview

A Review of Capabilities and Scope for Hybrid Integration Offered by Silicon-Nitride-Based Photonic Integrated Circuits

by Frederic Gardes, Afrooz Shooa, Greta De Paoli, Ilias Skandalos, Stefan Ilie, Teerapat Rutirawut, Wanvisa Talataisong, Joaquín Faneca, Valerio Vitali, Yaonan Hou, Thalía Domínguez Bucio, Ioannis Zeimpekis, Cosimo Lacava and Periklis Petropoulos

Sensors 2022, 22(11), 4227; https://doi.org/10.3390/s22114227 - 1 Jun 2022

Cited by 38 | Viewed by 7431

Abstract

In this review we present some of the recent advances in the field of silicon nitride photonic integrated circuits. The review focuses on the material deposition techniques currently available, illustrating the capabilities of each technique. The review then expands on the functionalisation of [...] Read more.

In this review we present some of the recent advances in the field of silicon nitride photonic integrated circuits. The review focuses on the material deposition techniques currently available, illustrating the capabilities of each technique. The review then expands on the functionalisation of the platform to achieve nonlinear processing, optical modulation, nonvolatile optical memories and integration with III-V materials to obtain lasing or gain capabilities. Full article

(This article belongs to the Special Issue Silicon Photonics: A Theme Issue in Honor of Professor Richard A. Soref)

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32 pages, 7918 KiB

Open AccessEditor’s ChoiceReview

Non-Hermitian Sensing in Photonics and Electronics: A Review

by Martino De Carlo, Francesco De Leonardis, Richard A. Soref, Luigi Colatorti and Vittorio M. N. Passaro

Sensors 2022, 22(11), 3977; https://doi.org/10.3390/s22113977 - 24 May 2022

Cited by 31 | Viewed by 5553

Abstract

Recently, non-Hermitian Hamiltonians have gained a lot of interest, especially in optics and electronics. In particular, the existence of real eigenvalues of non-Hermitian systems has opened a wide set of possibilities, especially, but not only, for sensing applications, exploiting the physics of exceptional [...] Read more.

Recently, non-Hermitian Hamiltonians have gained a lot of interest, especially in optics and electronics. In particular, the existence of real eigenvalues of non-Hermitian systems has opened a wide set of possibilities, especially, but not only, for sensing applications, exploiting the physics of exceptional points. In particular, the square root dependence of the eigenvalue splitting on different design parameters, exhibited by 2 × 2 non-Hermitian Hamiltonian matrices at the exceptional point, paved the way to the integration of high-performance sensors. The square root dependence of the eigenfrequencies on the design parameters is the reason for a theoretically infinite sensitivity in the proximity of the exceptional point. Recently, higher-order exceptional points have demonstrated the possibility of achieving the nth root dependence of the eigenfrequency splitting on perturbations. However, the exceptional sensitivity to external parameters is, at the same time, the major drawback of non-Hermitian configurations, leading to the high influence of noise. In this review, the basic principles of PT-symmetric and anti-PT-symmetric Hamiltonians will be shown, both in photonics and in electronics. The influence of noise on non-Hermitian configurations will be investigated and the newest solutions to overcome these problems will be illustrated. Finally, an overview of the newest outstanding results in sensing applications of non-Hermitian photonics and electronics will be provided. Full article

(This article belongs to the Special Issue Silicon Photonics: A Theme Issue in Honor of Professor Richard A. Soref)

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