Showing papers on "Optical communication published in 2023"

Integrated sensing and communication in an optical fibre

Abstract: The integration of high-speed optical communication and distributed sensing could bring intelligent functionalities to ubiquitous optical fibre networks, such as urban structure imaging, ocean seismic detection, and safety monitoring of underground embedded pipelines. This work demonstrates a scheme of integrated sensing and communication in an optical fibre (ISAC-OF) using the same wavelength channel for simultaneous data transmission and distributed vibration sensing. The scheme not only extends the intelligent functionality for optical fibre communication system, but also improves its transmission performance. A periodic linear frequency modulation (LFM) light is generated to act as the optical carrier and sensing probe in PAM4 signal transmission and phase-sensitive optical time-domain reflectometry (Φ-OTDR), respectively. After a 24.5 km fibre transmission, the forward PAM4 signal and the carrier-correspondence Rayleigh backscattering signal are detected and demodulated. Experimental results show that the integrated solution achieves better transmission performance (~1.3 dB improvement) and a larger launching power (7 dB enhancement) at a 56 Gbit/s bit rate compared to a conventional PAM4 signal transmission. Meanwhile, a 4 m spatial resolution, 4.32-nε/[Formula: see text] strain resolution, and over 21 kHz frequency response for the vibration sensing are obtained. The proposed solution offers a new path to further explore the potential of existing or future fibre-optic networks by the convergence of data transmission and status sensing. In addition, such a scheme of using shared spectrum in communication and distributed optical fibre sensing may be used to measure non-linear parameters in coherent optical communications, offering possible benefits for data transmission.

Third-Order Optical Nonlinearities of 2D Materials at Telecommunications Wavelengths

Abstract: All-optical signal processing based on nonlinear optical devices is promising for ultrafast information processing in optical communication systems. Recent advances in two-dimensional (2D) layered materials with unique structures and distinctive properties have opened up new avenues for nonlinear optics and the fabrication of related devices with high performance. This paper reviews the recent advances in research on third-order optical nonlinearities of 2D materials, focusing on all-optical processing applications in the optical telecommunications band near 1550 nm. First, we provide an overview of the material properties of different 2D materials. Next, we review different methods for characterizing the third-order optical nonlinearities of 2D materials, including the Z-scan technique, third-harmonic generation (THG) measurement, and hybrid device characterization, together with a summary of the measured n2 values in the telecommunications band. Finally, the current challenges and future perspectives are discussed.

Orbital Angular Momentum Beams for High-Capacity Communications

Abstract: There is a growing interest in structured light, especially orbital angular momentum (OAM) beams, due to its unique amplitude and phase structure. Multiple orthogonal OAM beams can be utilized to enable high-capacity communication systems in various scenarios. This review will discuss the properties, challenges, advances, and perspectives of OAM-based optical communications, including the following (a) basic multiplexing and encoding links; (b) OAM-based communication in free space and fiber; (c) technical hurdles; (d) mitigation approaches; (e) encoded quantum communications; (f) advanced topics including different frequency ranges and novel beams; and (g) ecosystem and commercialization.

Bidirectional and Dual‐Mode Organic Photodetector Enables Secure Ultraviolet Communication

Abstract: Traditional optical communication mode with single-band photodetector depicts terrible confidentiality and it depends on sophisticated cryptography schemes to obtain a secure communication process. Dual-band photodetectors have potential to realize a secure optical communication with a straightforward optical encryption strategy. However, previous reports of dual-band organic photodetectors (OPD) relied on the multi-stacked photosensitive layers thus there remain challenges in spectral matching and interfaces contacting. Here, a structurally simple bidirectional and UV–vis dual-band OPD is proposed, with single photosensitive layer sitting between electrodes. By elaborately regulating the optical field distribution and vertical phase segregation of the bulk heterojunction (BHJ), this OPD presents completely distinct spectral response ranges under bidirectional illuminations. Finally, this OPD outputs outstanding self-powered UV and vis dual-band responsivities (up to 30 and 50 mA W−1) as the light illuminates from forward and backward direction, respectively. In addition, a stable and reliable optical communication system is realized based on this OPD where the UV response conveys valid information and further superimposes vis response for encryption. This design concept offers a simple alternative for achieving varied response windows and opens up a novel optical encryption method, which has potential be applied in a close-range private communication process.

Optical network on chip: design of wavelength routed optical ring architecture

Abstract: Network on chip (NoC) technology has now achieved a mature stage of development as a result of their use as a key component in many successful commercial devices. As multiprocessors continue to scale, these ship based electronic networks are more challenging to meet their power budget communication requirements. Innovative technology is emerging with the aim of offering shorter latencies and greater bandwidth with lower power consumption. Ring topology provides superior results among the all wavelength routed topologies in the chip optical network. In this paper, we proposed an optical ring network-on-chip (ORNoC) architecture which is contention free. Communication matrix is used to assign a single waveguide/wavelength pair to implement simultaneous communications. The design constraints for the proposed architecture will be wavelength reused on a single waveguide for multiple communications. We imply automatic wavelength/waveguide assignment for effective design and will prove that the proposed architecture can connect more number of nodes and less wavelengths per waveguide.

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.

Dynamics and feedback sensitivity of vertical-cavity surface-emitting lasers with arbitrary optical feedback intensity

Abstract: Vertical cavity surface emitting lasers (VCSELs) are the key laser sources in the high-performance computers (HPCs) and data centers (DCs). The explosive growth of data traffic in the HPCs and DCs requires increased bandwidths of VCSELs. In this paper, we deduce the Time-Delay (T-D) model considering the multiple round trips of light in VCSELs with an optical feedback cavity to enhance the modulation bandwidth. The T-D model is suitable for the VCSEL with an arbitrary optical feedback intensity. The influences of the round trip time m of light in the optical feedback cavity on the intensity-modulation responses with strong and weak optical feedback are studied. The feedback coefficients considering the multiple round trips of light in the optical feedback cavity and the dispersions of the distributed Bragg reflector are deduced, and are suitable for the arbitrary optical feedback intensity. The feedback coefficients are influenced by the value of m and the optical feedback intensity, and decrease as the value of m under arbitrary optical feedback intensity increases. The feedback coefficients under strong optical feedback are larger than that under weak optical feedback with the same value of m. The theories are useful for the high-speed VCSELs with optical feedback.

Current status of NASA’s Low-Cost Optical Terminal (LCOT) at Goddard Space Flight Center

Abstract: This paper provides the status of ongoing work at NASA-Goddard Space Flight Center (GSFC) to build a low-cost flexible ground terminal for optical communication. For laser communication to be cost-effective for future missions, a global network of flexible optical terminals must be put in place. There is a need for a single ground terminal design capable of supporting multiple missions ranging from LEO to lunar distances. NASA’s Low-Cost Optical Terminal (LCOT) has a single modular design that can be quickly reconfigured to support different laser communications missions. The LCOT prototype uses a 70cm commercially available telescope designed with optical and quantum communications in mind. This telescope is currently being integrated with a state-of-the-art adaptive optics system, and novel high-power laser amplifier demonstrate its utility as an optical communications receiver by receiving a downlink from the recently launched Laser Communication Relay Demonstration (LCRD). LCOT uses commercially available components wherever possible, and where commercial options are not available, the LCOT team works with vendors to create commercial options. This paper discusses the development progress for the blueprint of NASA’s future global ground terminal network.

10-Gbps visible light communication in a 10-m free space based on violet series-biased micro-LED array and distance adaptive pre-equalization.

Abstract: In this paper, we fabricated a 3×3 violet series-biased micro-LED array with high-output optical power and applied it in high-speed and long-distance visible light communication. By employing the orthogonal frequency division multiplexing modulation scheme, distance adaptive pre-equalization, and a bit-loading algorithm, record data rates of 10.23 Gbps, 10.10 Gbps, and 9.51 Gbps were achieved at 0.2 m, 1 m, and 10 m, respectively, below the forward error correction limit of 3.8×10-3. To the best of our knowledge, these are the highest data rates achieved by violet micro-LEDs in free space and the first communication demonstration beyond 9.5 Gbps at 10 m using micro-LEDs.

Optical Communication Infrastructure in New Generation Mobile Networks

Abstract: ABSTRACT In this study, predictions by leading network technology companies and current literature on 5 G technologies have been investigated to shed a light on the foreseeable future of the developing communication systems infrastructure. Research has been carried out on the new-generation optical communication infrastructure, which is developing in parallel with the requirements of 5 G and beyond mobile communication systems, and optical-wireless communication (OWC), free-space optical communication (FSOC), visible-light communication (VLC), and optical-camera communication (OCC) is presented. Also, there is information about fiber-wireless (FiWi) and radio-over fiber (RoF) transmission systems and FSO system integration (RoFSO), which finds use as an infrastructure component in the next-generation high-frequency communication.

Cooperative relay orbital satellite optical communication under turbulent channels: Performance analysis

Abstract: Free-space optical (FSO) or laser satellite communication (SatCom) can be enhanced to mitigate turbulent channels by using relay communication, which provides main advantages including lower mass, lower consumption, better throughput, and lower cost. Furthermore, laser SatCom is inherently resistant to jamming, interception, and interference. This letter provides a theoretical and simulation analysis of downlink optical cooperative relay SatCom. The performance analysis for the proposed model is investigated using outage probability (OP) and bit error rate (BER) with intensity modulation direct detection (IM/DD) technique and decode and forwarding (DF) technology. The average aperture radius and operating wavelength are studied to illustrate the impact of the number of relays on the required aperture diameter. Closed forms for OP and BER are derived for the cooperative relay optical SatCom in order to express the results in the form of elementary functions, taking into account the impact of the ideal number of relays, significant design considerations, operating wavelengths, and zenith angles on the overall system performance. The collected findings demonstrate that our cooperative relays outperform both serial and direct link benchmarks for a variety of system characteristics.

Comparing of the effect of changing weather factors on FSO communication system performance using iterative improvement technique

Abstract: The issue of providing a communications system, with large frequencies within the range, is one of the main challenges that are required to be provided to users of the free-space optical communications service. In this work, the factors affecting the quality of performance of a free communication system (10 Gbps) were investigated and studied. The obtained results of this system are compared with two wavelengths 1550 nm and 850 nm in terms of farthest data transmission distance, BER, factor of quality and chart of eye in different weather situations using an iterative optimization.

Fiberless optical communication: issues and challenges

Abstract: Abstract To fulfill the requirement of high data rate with variable quality of service, optical wireless communication is a better option in comparison to existing RF system and is a favorable technological candidate for future optical communication. In wireless optical communication, information is transmitted by propagation of optical wave through the atmosphere. The detrimental effects of channel parameters can acutely limit the utility of an optical wireless communication system. The paper first reviews different channel models in the context to outdoor wireless communication. Different impairments that affect the performance of outdoor optical communication systems and different techniques to mitigate these impairments are then investigated. The upper layer protocols for free space optical communication are also discussed.

Multilevel polarization shift keying modulation for turbulence-robust underwater optical wireless communication.

Abstract: Turbulence is an intractable issue for underwater optical wireless communication (UOWC). Most literature has been mainly focused on the modeling of turbulence channels and performance analysis rather than mitigation of the turbulence effect, especially from the experimental aspects. In this paper, a multilevel polarization shift keying (PolSK) modulation based UOWC system is established utilizing a 15 m-long water tank, and the system performance is investigated under specific temperature gradient-induced turbulence and various transmitted optical powers. Experimental results show the feasibility of the PolSK in alleviating the effect of turbulence, and the bit error rate performance significantly outperforms traditional intensity-based modulation schemes which have difficulty in obtaining an optimal decision threshold in a turbulence channel.

Experimental demonstration of an 8 Gbit/s free-space secure optical communication link utilizing all-optical chaos modulation

Abstract: For the first time, to the best of our knowledge, we experimentally demonstrate a high-speed free-space secure optical communication system based on all-optical chaos modulation. The effect of atmospheric turbulence on optical chaos synchronization is experimentally investigated via a hot air convection atmospheric turbulence simulator. It is shown that, even under moderately strong turbulent conditions, high-quality chaos synchronization could be obtained by increasing the transmission power. Moreover, a secure encryption transmission experiment using a high bias current induced chaotic carrier for 8-Gbit/s on-off-keying data over a ∼10-m free-space optical link is successfully demonstrated, with a bit-error rate below the FEC threshold of 3.8 × 10 −3 . This work favorably shows the feasibility of optical chaotic encryption for the free-space optical transmission system.

Channel Measurements for Switching Strategies in Hybrid RF/Optical Communications

Abstract: Free space optical (FSO) communication links increase data rate, reduce size and power, and increase security. These criteria are particularly important in space communication. Increasing mission complexity and crowding of lower frequency bands is driving the need for optical communications. This makes FSO communication technology extremely attractive, and there is significant ongoing work towards the development of FSO transceivers, ground stations, and relays. Notable projects include the Laser Communications Relay Demonstrator (LCRD), Integrated LCRD Low-Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T), and CubeSat Laser Infrared Crosslink (CLICK) CubeSats. These technologies will eventually operate in unison with existing Radio Frequency (RF) systems, but there is little experimental investigation of such hybrid networks. This paper presents some experimental underpinnings of switching strategies for hybrid RF/FSO systems in various attenuation conditions. A 170 m optical path was constructed in an enclosed test chamber where atmospheric conditions can be tightly controlled. The performance of a 1550 nm infrared FSO link was evaluated in this chamber under varying conditions of turbulence and jitter. The system will eventually be used to investigate switching criteria between the FSO and RF channels. Optimizing the use of RF/FSO communication links will allow data rate, size, power, and security improvements. Therefore, this research will help to mature the network architecture and improve the performance of communication networks to be used for LEO, GEO, Lagrange, Lunar missions and beyond.

65,536-ary orbital angular momentum-shift keying free-space optical communication based on few-shot learning.

Abstract: In an orbital angular momentum-shift keying free-space optical (OAM-SK FSO) communication system, precisely recognizing OAM superposed modes at the receiver site is crucial to improve the communication capacity. While deep learning (DL) provides an effective method for OAM demodulation, with the increase of OAM modes, the dimension explosion of OAM superstates results in unacceptable costs on training the DL model. Here, we demonstrate a few-shot-learning-based demodulator to achieve a 65,536-ary OAM-SK FSO communication system. By learning from only 256 classes of samples, the remaining 65,280 unseen classes can be predicted with an accuracy of more than 94%, which saves a large number of resources on data preparation and model training. Based on this demodulator, we first realize the single transmission of a color pixel and the single transmission of two gray scale pixels on the application of colorful-image-transmission in free space with an average error rate less than 0.023%. This work may provide a new, to the best of our knowledge, approach for big data capacity in optical communication systems.

Theoretical investigations of weakly- and strongly-coupled multi-core fibers for the applications of optical submarine communications under power and fiber count limits.

Abstract: The practical cable design for optical submarine communications has a limited fiber pair count due to the mechanical considerations of cable weight and size. Consequently, multi-core fibers (MCFs) could exhibit higher capacity than conventional single-mode fibers (SMFs) thanks to space division multiplexing (SDM). That is because the power supply to a submarine cable is fed by the voltage difference between shores. Under the power-limited condition, SDM improves the cable capacity by using more paths which outperforms the SMF link whose capacity approximately complies with a logarithmic relationship to optical power. At the same time, fiber nonlinearity can be alleviated by the reduced power density of transmitted light in MCFs, due to the increased spatial diversity and mode coupling among coupled cores. In this work, we theoretically investigate the potentials of MCFs including weakly-coupled multicore fiber (WC-MCF) and strongly-coupled multicore fiber (SC-MCF) as the propagation media for submarine communications across the Atlantic and the Pacific. To fairly compare the performances of SMFs- and MCFs-based submarine cables, the Gaussian noise (GN) model for SDM links is employed to optimize the systematic settings including spatial multiplicity and single span length. Then, we develop an SDM and wavelength division multiplexing (WDM) fiber transmission model based on coupled nonlinear Schrodinger equations (CNSE) to investigate the optical filed coupling effect in MCFs-based cables. The developed transmission model has been self-examined by measuring the inter-core crosstalk (IC-XT) and spatial mode dispersion (SMD), referring to the set values. As indicated by the theoretical analysis, the WC-MCFs cable exhibits a larger capacity than the SMFs cable, when the fiber pair count is limited below 32. Moreover, the SC-MCFs cable outperforms the WC-MCFs cable thanks to the reduced fiber nonlinearity due to the random mode coupling and the assistance of multiple-input and multiple-output digital signal processing (MIMO-DSP). At last, the marginal influences of IC-XT, SMD, and insertion loss of Fan-in and Fan-out couplers are also analyzed for the MCFs cable.

A new duplex optical communication scheme based on quantum well diode

Abstract: With the advent of the Internet of things (IoT) era, the existing communication methods have been difficult to meet the high-speed needs and various complex scenarios. Especially in occasions with large electromagnetic interference, such as tunnels, oceans and inspection wells, the existing electromagnetic communication is difficult to meet people’s communication needs. Therefore, as a new communication method, optical communication has the advantages of strong anti-interference ability, high speed and high confidentiality. It has gradually entered people’s vision. And the development of the third generation of semiconductors has also achieved great technological breakthroughs in semiconductor lighting materials and devices, which provides us with a new idea. The supplementary scheme applied to the mainstream electromagnetic communication is innovated. We propose a new optical communication method by using quantum well diode (QWD) chip and combining its physical mechanism of coexistence of luminescence and detection. We use two identical chips as transmitter and receiver, which communicate with each other by light and support software definition. This confirms that it can receive signals while transmitting. We interpret and characterize this communication scheme from three aspects: electricity, optics and communication. This communication method will mean the integration of the transmitter and receiver, thus saving half of the channel cost. The experiment innovates from the most basic devices, integrates new physical phenomena and energy band theory, realizes the exploration of a single device for optical communication with integrated transceiver, and gives birth to a new communication idea and means, which is of great significance for the supplement of communication means in the era of the Internet of things.

Wave-based signal security and privacy studies using automatic high-bit-rate optical communications with quantum cryptographic

Abstract: The information transfer through the fibers, which converts the electronic signals into light and employs the light emitting and the light source which enables the information transfer, is known as optical communications. Noise reduction is needed for information transfer. More noise is transferred in the optical fiber, which is the main problem with the information transfer. Then the communication multiplies the bandwidth, and the optical communication can be enabled. The high modulation method and quantum cryptographic system manage the modulation method to reduce noise from information transmission. The guided waves for many communication purposes, multi-rate communication, and non-moderate communication can be used in this research. The application of the quantum cryptographic system and the modulation for analog signal processing keep the noise reduction, bandwidth, and optical communication can be improved by up to 97% of noise can be released in the fiber optic for the mortification of the communication system. The noise reduction can be made with optical communication. Up to 80% of noise can be removed in the modulation and the quantum cryptographic. Automatic improvement of the high bit rate communication using the quantum cryptographic and the system to reduce the multiplication and bandwidth using the quantum cryptographic system.

A combined fibre/free-space-optical communication system for long-haul wireline/wireless transmission at millimetre-wave/sub-THz frequencies

Abstract: Abstract The demands of the technologies of the future such as autonomous vehicles, Internet of Things and mixed reality require communications platforms equipped to handle huge quantities of data. Higher frequency communication bands are attractive but have limitations in terms of data loss particularly during wireless transmission. Free-space optical (FSO) communication, which transmits optical signals through free-space by modulating laser light, is one option for better wireless signal delivery. Here we report a platform combining multiple transmission media of 40-km single-mode fibre, with 1.2-km FSO communication, and short range (0.5-2 m) radio-frequency wireless. We demonstrate sufficiently low bit error rates and error vector magnitudes at sub-terahertz frequencies, satisfying the requirement of 5 G new radio communications applications.

High speed free-space optical communication using standard fiber communication component without optical amplification

Abstract: Free-space optical communication (FSO) can achieve fast, secure and license-free communication without need for physical cables, making it a cost-effective, energy-efficient and flexible solution when the fiber connection is absent. To establish FSO connection on-demand, it is essential to build portable FSO devices with compact structure and light weight. Here, we develop a miniaturized FSO system and realize 9.16 Gbps FSO between two nodes that is 1 km apart, using a commercial fiber-coupled optical transceiver module with no optical amplification. Basing on the home-made compact 90 mm-diameter acquisition, pointing and tracking (APT) system with four-stage close-loop feedback, the link tracking error is controlled at 3 {\mu}rad and results an average coupling loss of 13.7 dB. Such loss is within the tolerance of the commercial optical communication modules, and without the need of optical amplifiers, which contributes to the low system weight and power consumption. As a result, a single FSO device weighs only about 12 kg, making it compact and portable for potential application in high-speed wireless communication. Our FSO link has been tested up to 4 km, with link loss of 18 dB in the foggy weather in Nanjing, that shows longer distances can be covered with optical amplification.

Free-Space Visible Light Communication with Downstream and Upstream Transmissions Supporting Multiple Moveable Receivers Using Light-Diffusing Fiber

Abstract: We demonstrate a free-space bi-directional visible-light-communication (VLC) system using a light-diffusion-fiber (LDF) optical antenna. It allows 360 o field-of-view (FOV) noncontact and moveable VLC detection, achieving 210-Mbit/s downlink and 850-Mbit/s uplink transmissions.

Performance Analysis of Optical Reflecting Surface-Assisted Optical Space Shift Keying-based MIMO-FSO system

Abstract: —Recently, the use of reconfigurable intelligent sur- faces (RIS) has gained popularity and is emerging as a promising technique to provide improved link reliability and enhanced coverage area. In this paper, we propose an optical reflecting surface (ORS)-assisted free space optics (FSO) communication system, which is based on optical space shift keying (OSSK) technique. Specifically, the closed-form expression for probability density function (PDF) of the ORS-assisted FSO channel is derived over Malaga turbulence model. Further, we have obtained the moment generating function (MGF) of the instantaneous signal-to-noise ratio (SNR) of the overall OSSK-based multiple- input multiple-output (MIMO)-FSO system. Using the derived channel statistics, an upper bound expression for the average bit error rate (BER) and a lower bound for the ergodic capacity are derived. Further, the asymptotic BER is utilized to calculate the diversity gain of the system. Numerical results are provided to corroborate the theoretical analysis of the system, along with insightful discussions. It is observed from the numerical results that the atmospheric turbulence and pointing errors have a negligible effect on the performance of the proposed system. Finally, a trade-off is noticed with respect to the average BER performance versus the spectral efficiency of the proposed system.

Comparison between various dispersion compensation schemes in optical fiber communication system

Abstract: Abstract Nowadays, the optical fiber communication system has great importance in the communication area. Although the optical fiber communication system has many favorable circumstances, the dispersion was considered one of the main problems. In this paper, the comparison between the design and simulation of different dispersion compensation schemes was displayed. There are different kinds of optical fiber dispersion compensation systems such as fiber Bragg grating (FBG) and dispersion compensation fiber (DCF) are extensively used for optical communication systems. They are usually considered imperative techniques to compensate for the dispersion. The simulation results have been analyzed depending on various parameters by utilizing advanced Opti-System software. The best performance of the system is when the bit error rate (BER) reaches to 1.7 × 10−12 at 1550 nm wavelength and the Q-factor is 6.9 at the 0.000195 eye opening. The modal was simulated using the appropriate parameters which include CW laser wavelength, fiber length (km), and attenuation coefficient (dB/km) at the transmitter side. Three various parameters were tested such as BER, Q factor, and eye-opening.

Fiber Coupling Efficiency of Partially Coherent Gaussian Beam in Ground-to-HAP Free-Space Optical Communication Systems

Abstract: In this paper, we propose a novel model of fiber coupling efficiency based on the second-order moment interaction of optical field in the oblique atmospheric channel laser communication system, where the turbulence of the partially coherent Gaussian beam propagation can vary in intensity from weak to strong. Based on this model, we analyze the impacts of channel characteristics, reception aperture, and other key system parameters on the fiber coupling efficiency of our considered systems. The numerical results validate the correctness of our model and analysis. Moreover, we show how fiber coupling efficiency can be improved by judiciously selecting the wavelength, coupling lens aperture, focal length, beam size, and the coherence. The results presented in this paper provide pivotal insights into designing practical transmission schemes in optical communication systems.