We propose and experimentally demonstrate a novel multimode ultra-compact mode (de)multiplexer for highly integrated on-chip mode-division multiplexing systems. This device is composed of wide divergence angle asymmetric Y-junction based on subwavelength structure optimized using an inverse design method. The proposed occupied footprint only 2.4 × 3 µm2. measured insertion loss crosstalk were less than 1dB -24 dB from 1530 nm to 1590 both TE0 TE1 mode, respectively. Likewise, three...

We propose and experimentally demonstrate a novel ultracompact dual-mode waveguide crossing based on subwavelength multimode-interference couplers for densely integrated on-chip mode-division multiplexing system. By engineering the lateral-cladding material index manipulating phase profiles of light at nanoscale using an improved inverse design method, structure could theoretically realize identical beat length both TE0 TE1, which can reduce scale device greatly. The fabricated occupied...

An ultracompact broadband dual-mode 3 dB power splitter using inverse design method for highly integrated on-chip mode (de) multiplexing system is proposed and experimentally demonstrated. A convertor based on subwavelength axisymmetric three-branch waveguide utilized to convert TE0 TE1 three intermediate fundamental modes. The topology constraint of the nanostructures enables optimized device achieve a strict 50:50 splitting ratio over broad wavelength range from 1.52 1.60 µm. fabricated...

Inverse-designed free-form nanophotonic structures have shown great potential in designing ultra-compact integrated photonic devices, but strict fabrication requirements may hinder further applications. We propose here a photonic-crystal-like (PhC-like) subwavelength structure, which is insensitive to the lag effect that most common error. A colorless 3 dB coupler employing such structure designed, fabricated, and characterized. With only one-step etching, coupling region of our final device...

In this paper, we proposed an improved mobile fronthaul architecture employing the SNR-improved delta-sigma digitization scheme and 4-level pulse amplitude modulation (PAM-4) format. Different from traditional 2-bit quantization, deploys two-fold which uses 1-bit modulator to quantize signal, another in-band noise. A significant reduction of noise can be achieved only applying a differentiator, bringing about much better shaping performance. Meanwhile, two streams combined transmitted in...

We propose a novel method to simultaneously improve the physical layer security and transmission performance of orthogonal frequency division multiplexing (OFDM) passive optical network system by using chaos fractional Fourier transform (FrFT) techniques. The designed 3-D chaotic sequences are used form training sequence for time synchronization, perform OFDM subcarriers masking, control order FrFT operation. analyses show that whole key space size proposed scheme could be beyond 10 <sup...

A dual-field encryption scheme of an orthogonal frequency division multiplexing passive optical network (OFDM-PON) is proposed based on analog–digital hybrid chaotic system. In our scheme, the downstream data are encrypted in field, and upstream electrical field. The system circumvents security vulnerabilities both analog digital chaos, e.g., periodicity chaos masked by one, time delay signature concealed injecting chaos. Meanwhile, key space dimension enlarged. Simulation results show...

We propose and numerically investigate a chaotic optical coherent secure communication scheme, which supports long-haul transmission for signals in advanced modulation formats. A hybrid chaos system is designed with coordination of digital analog signals. The entropy source provides broadband signal, could serve as the carrier to load quadrature amplitude (QAM) data. Simultaneously, binary signal generated from transmitted establish synchronization. Coherent detection utilized at receiver,...

We propose and experimentally study a coherent optical secure transmission system based on one dual-polarization in-phase quadrature modulator (IQM). One beam of the polarized light is used to generate broadband chaos by configuring nonlinear opto-electronic oscillator while other carries encrypted signal. The signal obtained through sequential encryption analog digital chaos. mutual mask hybrid chaotic signals can effectively enhance security performance. Moreover, varying depth vectors,...

With the development of highly densified photonic integrated circuits, optical cross nodes number exhibits dramatically increasing. Not only efficient but also ultra-compact waveguide crossings are required to materialize full potential silicon photonics for on-chip intercross connect. In this work, we proposed several inverse-designed 4 × 4, 5 and 6 star-crossings based on photonic-crystal-like (PhC-like) subwavelength structures, which have ultra-high port density about 7.1 μm2/port, 5.83...

We propose and experimentally demonstrate a novel physical layer encryption scheme for high-speed optical communication. A 10 Gb/s on-off keying signal is secretly transmitted over 100 km standard single-mode fiber. The intensity-modulated message secured by the mechanism, which composed of an external noise source internal time-delayed feedback loop. serves as entropy with sufficient randomness. loop structure in transmitter introduces time-domain key space, corresponding open-loop...

We propose and experimentally demonstrate a novel ultracompact silicon polarization rotator based on equivalent asymmetric waveguide cross section in only single-step etching procedure for densely integrated on-chip mode-division multiplexing system. In the conventional mode hybridization scheme, is employed to excite hybridized modes realize high performance with compact footprint extinction ratio. However, fabrication complexity severely restricts potential application of section. use...

We propose a model-free time delay signature (TDS) extraction method for optical chaos systems. The TDS can be identified from series without prior knowledge of the actual physical processes. In secure communication systems, carrier is usually generated by laser diode subject to opto-electronic/all-optical delayed feedback. One most important factors security considerations concealment TDS. So far, statistical analysis methods such as autocorrelation function (ACF) and mutual information...

The utilization of metamaterials plays a pivotal role in integrated photonics. precise design enables them to finely manipulate light, resulting an ultra-compact footprint and exceptional performance that cannot be achieved by traditional structures. conventional methods for metamaterial design, however, encounter challenges from intricate targets. Although attempts have been made apply inverse metamaterials, there is still need highly intelligent, low-computation method, easy-to-fabricate...

Photonic RF memory (PRFM) that integrates advanced functions and comprehensive information dimensions is critical for electronic countermeasure applications with high operating frequencies wide bandwidths. In this paper, we report a novel programmable PRFM supporting ultra-high capacity storage functionally-integrated radar jamming. On the one hand, bandwidth scalability are further developed by response optimization founded on signal-carrier separation strategy. other single-false-target...

Abstract The increasing demand for communication capacity has led to extensive exploration of hybrid multiplexing technologies that combine multiple wavelengths, modes, and polarization. Nevertheless, designing mode converters remains challenging. Reconfigurable scalable multichannel parallel offer an attractive solution efficient switching with a small footprint. In this paper, compact high‐performance dual‐polarization order converter based on metamaterials is proposed, which consists two...

The recent advancements in nano-optics have created a strong demand for ultra-compact, miniaturized photonic devices. However, the mainstream inverse design algorithms face challenges achieving compact size, efficient performance, and superior process manufacturability simultaneously. present study proposes an exceptionally segmented hierarchical variable step-size binary search-based digital method, aiming to transcend these limitations. concept of “pixel splitting” is introduced first time...

We propose a scheme whereby time domain fractional Fourier transform (FRFT) is used to post process the optical chaotic carrier generated by an electro-optic oscillator. The delay signature of dynamics successfully masked FRFT when some conditions are satisfied. Meanwhile dimension space physical parameters increased. Pseudo random binary sequence (PRBS) with low bit rate (hundreds Mbps) introduced control FRFT. carrier, and PRBS covered each other so that eavesdropper has search whole key...

We propose and experimentally demonstrate a novel ultracompact multimode waveguide crossing. The compact asymmetric subwavelength Y-junction is introduced to convert the high-order modes into fundamental ones, enabling one implement three or more simultaneously in subsequent processing. Our proposed device occupied only footprint of 34 × μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . measured results indicate our fabricated...

An analog–digital hybrid optical chaos source and a corresponding secure key distribution (SKD) scheme are proposed. electro-optic feedback loop is introduced to enhance the robustness of chaotic semiconductor lasers. The source, which can adopt robust digital synchronization strategies, could generate broadband analog signal high dynamical complexity. Furthermore, reduces requirement on processing speed components simplifies system structure markedly. For demonstrating, we build SKD with...

A novel automatic bias control (ABC) method which could lock an optical IQ modulator at arbitrary points is proposed and experimentally demonstrated for the first time. In method, sequences parameters of used dither signals switch applied voltages are specially designed to minimize influence power coupling between three MZMs in nonideal extinction ratios. By this way, precise electro-optical characteristic these can be obtained by calculating relevancy produced output signal. Based on...

We propose and demonstrate an identity authentication method in the orthogonal frequency division multiplexing passive optical network (OFDM-PON) by recognizing device fingerprints of units (ONUs). Signal decomposition methods based on wavelet transform are implemented to extract feature matrixes during pre-process samples, then a trained 2-D convolutional neural (2D-CNN) is applied classify identify these matrixes. Experimental results show that legitimate ONUs can be successfully...

A chaotic-shift-keying (CSK) scheme is designed based on a chaos system with electro-optical hybrid time delayed feedback structure. By switching the delay parameter as message feeding method, generated chaotic signal no longer suffered from return map attack, which an innate vulnerability of traditional CSK. When coupling seed electrical and nonlinear optical loop carefully weighed, this CSK shows good robustness in terms handling noise for transmitting digital signals. demodulating signals...

We experimentally demonstrate a chaotic synchronization scheme based on the electro-optic hybrid entropy sources. The chaos method is validated that 200 km high-level can be attained and distance further extended. digital signal induced has good robustness against potential distortions in long-haul optical transmission. On basis of strategy, correlated random bit generation (CRBG) with rate 1.25 Gb/s proposed. generated sequences (CRBSs) pass all NIST tests. Meanwhile, data encryption robust...