Coarse WDM in Metropolitan Networks: Challenges, Standards, Applications, and Future Role

Abstract

Coarse Wavelength Division Multiplexing (CWDM) denotes a technology of diaphanous transport which aids to transmit simultaneously a large number of services across a single optical fiber. This technology relies on the usage of optical channels which are 20 nm from each other. These channels are employed in the CFO OPX products, which ranged from 1270 nm until 1610 nm, had been set in ITU-T G - 694.2 recommendations. ITU-T managed to determine 18 optical channels together, though 16 only are used in reality, in the case of using the two lowest channels which are avoided because of the excessive-high attenuation of glass. However, the review study presented in this paper deals with the CWDM technique as the best choice in decreasing capital expenditure after taking into consideration the simplicity of design, the capability of expanded transmission, low cost of components and reduction in operational cost. The paper also focused on the standards, applications and future role of the CWDM technique.

Integrated Sensor-Optics Communication System Using Bidirectional Fiber and FSO Channels and Hybrid Deep Learning Techniques

“…The integration aims to enhance reliability and extend the transmission distance of the fiber/FSO communication system with the sensor network, reaching remote optical network units (ONUs) and remote FBG sensing systems. CWDM Mux/Demux technology possesses an impressive capacity when it comes to effectively combining or separating signals that are traditionally considered incompatible, as reported by researchers references [23,24]. This remarkable capability of the CWDM Mux/Demux makes it an efficient and reliable technique for seamlessly integrating communication and an FBG-based sensor system.…”

Silicon-Nanowire-Based 100-GHz-Spaced 16λ DWDM, 800-GHz-Spaced 8λ LR-8, and 20-nm-Spaced 4λ CWDM Optical Demultiplexers for High-Density Interconnects in Datacenters

“…CWDM provides many advantages over DWDM due to its less strict prerequisites for the accurate control of diode laser oscillation frequency and broader available operating range in the wavelength domain. Additionally, CWDM devices must properly work within a wavelength range exceeding 60 nm, as the operating point is spaced by 20 nm [5][6][7]11]. Furthermore, the optical DeMUX at the receiver's end must possess the capability to handle arbitrary polarization input signals [28,30,35,36,40,42,47,49].…”

“…In light of recent increases in data traffic spurred by digital transformation and the advent of 6G mobile communication networks, there is a growing demand for more advanced optical multiplexing technologies like wavelength division multiplexing (WDM) or coherent phase modulation techniques, particularly in datacenter applications [1][2][3][4][5][6][7][8][9]. Silicon photonics stands out as a highly promising technological platform for the development of photonic integrated circuits (PICs) characterized by high bandwidth and low energy consumption.…”

Silicon-Nanowire-Type Polarization-Diversified CWDM Demultiplexer for Low Polarization Crosstalk

“…3 Wavelength crosstalk from neighboring channels. 4 Polarization crosstalk (TM 00 -mode) from the PSR. 5 No experimental data were shown for polarization crosstalk.…”

“…Four-channel coarse wavelength division multiplexing (CWDM) in the O-band spectral range is widely used in datacenter applications owing to its cost-effectiveness [ 1 , 2 , 3 , 4 ]. In optical transceivers, optical demultiplexers are essential for filtering WDM optical signals and spatially separating them into output ports at the receiver end.…”