Broadband, Low‐Crosstalk, and Massive‐Channels OAM Modes De/Multiplexing Based on Optical Diffraction Neural Network

Abstract

Optical communication technology based on the wavelength, time, polarization, and complex amplitude of light is approaching a bottleneck, while the spatial dimension is relatively unexplored. Orbital angular momentum (OAM) beams are an important group of spatial light beams that are promising for increasing the optical communication capacity based on their orthogonality. To effectively utilize this spatial dimension of light, broadband and low‐crosstalk OAM mode de/multiplexing devices are indispensable. In this work, by exploiting an optical diffraction neural network, a low‐crosstalk OAM de/multiplexer operating in the full C+L band is developed and demonstrated. The device can support 16 OAM modes (l = ±1 to ±8) with 5 phase plates (8‐level phase), and the designed insertion loss and average intermode crosstalk are better than −2.8 and −30.9 dB, respectively. In particular, multiplexing and demultiplexing are experimentally performed on the same device. The measured average insertion loss in mutltiplexing and demulteplexing is −6.1 to −5.4 and −6.8 to −5.8 dB, respectively, and the corresponding average intermode crosstalk is −27.2 to −22.7 and −26.5 to −22.4 dB. The results in this work have great application prospects for the design of mode de/multiplexers and mode division multiplexing communication systems.

Research Progress on Router Devices for the OAM Optical Communication

“…Multicasting Extended communication link [95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111][112] Switching Exchanging data [113][114][115][116][117][118][119][120][121][122][123][124][125][126][127] Filtering Extracting specific channel [128][129][130][131][132][133][134][135][136][137][138][139][140] Hopping Anti-interference [141][142][143][144]…”

“…Exchanging data [113][114][115][116][117][118][119][120][121][122][123][124][125][126][127] Filtering…”

“…For the OAM optical communication system, it might be useful to extend the employment of an OAM-based communications link in a multi-user environment, in which different OAM data channels could be selectively manipulated. One of the OAM-RDs that can realize channel switching plays an important role [113][114][115][116][117][118][119]. In 2013, Yue et al [120] experimentally demonstrated OAM-based reconfigurable optical switching functions when multiple OAM modes were used by switching n input modes with arbitrary OAM charges to n OAM modes with a desired number of charges.…”

Miniaturized optical vortex mode demultiplexer: Principle, fabrication, and applications

“…2019年, Fontaine等 [60] 提出了一种特殊的变 换方法, 用于将笛卡尔坐标系中的点(x, y)转换为 处理能力 [67−72] . 然而, 这些方法主要集中在对单个 涡旋光束的模式转换.…”

Broadband Diffractive Neural Networks Enabling Classification of Visible Wavelengths

“…[10] Various applications, from image processing to data encryption, have been demonstrated with DNNs using terahertz radiation. [17][18][19][20] Research efforts have focused on developing DNNs for visible wavelengths for potential novel applications including optical computing, fluorescence imaging, and 3D holographic displays. [21][22][23] However, shorter wavelengths present a challenge for DNNs in the context of fabricating submicrometer DOI: 10.1002/adpr.202300310 Diffractive neural networks (DNNs) are emerging as a new machine learning hardware based on optical diffraction with parallel and high-throughput information processing.…”