Current Issue : April-June Volume : 2024 Issue Number : 2 Articles : 5 Articles
This study aims to analyze the NRZ-OOK modulation format in free-space optical communication. Simulations were conducted to examine the influence of the SpS parameter and optical signal power at the input modulator on the average power of the modulated optical signal. The research employed a computer simulation approach, where the optical signal was transmitted through an optical path without cables, enabling fast data transmission and longer distances compared to wired media. The method used specifically uses a machine learning-based application, Python. The simulation results indicate that higher SpS values result in a more accurate and smoother optical signal representation. Furthermore, an increase in the optical signal power at the input modulator increases the average power of the modulated optical signal. However, negative optical power values do not hold any relevant physical meaning. The magnitude of the Pi_dBm value also affects the optical signal spectrum, with higher optical power generating more robust frequency components. Graphs with negative optical power exhibit significant noise due to distortion and non-linearity. The findings of this study provide a better understanding of the influence of these parameters in the NRZ-OOK modulation format for free-space optical communication....
A new method to measure laser phase noise and frequency stability based on the phasesensitive optical time-domain reflectometry is proposed. In this method, the laser under test is utilized in a phase-sensitive optical time-domain reflectometer, which employs phase-modulated dual pulses and acts as an optical frequency discriminator: laser frequency fluctuations are deduced from the analysis of the reflectometer data corresponded to phase fluctuations along the vibration-damped and thermally insulated fiber spool. The measurement results were validated by comparison with direct optical heterodyning of the tested and more coherent reference lasers. The use of dual pulses generated by an acousto-optic modulator makes it easy to adjust the time delay during measurements, which distinguishes favorably the proposed method from standard optical frequency discriminators. The method is suitable for testing highly coherent lasers and qualifying their parameters such as linear drift rate, random frequency walk rate, white frequency noise (which is directly related to laser instantaneous linewidth), and flicker noise level....
Over the past few decades, on-chip photonic integrated circuits based on silicon photonics (SiPh) platforms have gained widespread attention due to the fact that they offer many advantages, such as high bandwidth, low loss, compact size, low power consumption, and high integration with different photonic devices. The demand for high-speed and high-performance SiPh devices is driven by the significant increase in demand for Internet traffic. In photonic integrated circuits, controlling optical signals to make them circulate in a specific direction is a highly researched area of study. However, achieving a purely passive on-chip optical circulating network on a SiPh platform is very challenging. Therefore, we propose and demonstrate, through simulations, an on-chip optical circulator network on a silicon-on-insulator (SOI) platform. The proposed device can also support mode conversion. The proposed on-chip optical circulating network consists of two kinds of tailor-made multi-mode interferometer (MMI) structures and waveguide crossings. Through the optical power division and mode combination capabilities of the MMI, an optical circulating network supporting high optical isolation and mode conversion is achieved. The proposed optical circulating network has a loss of 1.5 dB at each output port, while maintaining a high isolation of 35 dB in the transmission window from 1530 nm to 1570 nm....
FTTH (Fibre to the Home) uses a fusion splice field-assembled optical connector. The fusion splice field-assembled optical connector is connected and assembled using a generic fibre fusion splicer. However, general purpose fusion splicers make the device difficult to operate in the installation field because the fusion splicer is too large and heavy to handle. As a result, the fibre optic splice often breaks during the optical connector assembly process. This makes it difficult to apply fusion-spliced optical connectors in the FTTH field. To solve this problem, this paper proposes a fusion splicer for FTTH that can perform fusion splicing using a wing-type sleeve optical connector. The proposed fusion splicer, with a connection module with a lifting/lowering function, is implemented to connect and protect the wing-type sleeve field-assembled optical connector. In addition, by eliminating the tube heater used as a connection protection method in the existing fusion splicer, the power module is reduced. The developed fusion splicer was evaluated for assembly reliability through splice loss measurements and a comparison of assembling time with the existing fusion splicer....
Silicon (Si) photonics has emerged as a prominent technology for meeting the escalating requirements of high-speed data transmission in optical communication systems. These systems need to be compact, energy-efficient, and capable of handling large amounts of data, driven by the advent of next-generation communication devices. Recently, there have been significant activities in exploring graphene within silicon-based components to enhance the overall performance metrics of optoelectronic subsystems. Graphene’s high mobility of charge carriers makes it appealing for the next generation of high-performance devices, especially in high-speed optoelectronics. However, due to its zero bandgap, graphene is unlikely to replace silicon entirely, but it exhibits potential as a catalyst for silicon-based devices, namely in high-speed electronics and optical modulators, where its distinctive characteristics can facilitate progress in silicon photonics and other fields. This paper aims to provide an objective review of the advances made within the realm of graphene-integrated Si photonics for high-speed light modulation and detection....
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