What are WDM, CWDM, CCWDM, DWDM, FWDM, LWDM Multiplexer

What is WDM

WDM (optical Division Multiplexing) is the technology to combine two or more optical carrier signals of different wavelengths (carrying various information) at the transmitting end through a Multiplexer coupled to the same optical fiber for transmission. At the receiving end the optical signals of various wavelengths are separated by Demultiplexer, and then restored to the original signal by the optical receiver for further processing. The main purpose of WDM is to increase the bandwidth capacity of optical fibers. Therefore, WDM systems are widely used by telecom operators to expand capacity through WDM without laying more optical fibers.

What is CWDM, CCWDM, DWDM, FWDM, LWDM

WDM solutions include CWDM (Coarse Wavelength Division Multiplexing), CCWDM (Compact Coarse Wavelength Division Multiplexing), DWDM (Dense Wavelength Division Multiplexing), FWDM (Filter Wavelength Division Multiplexing) and LWDM (LAN Wavelength Division Multiplexing).CWDM (Coarse Wavelength Division Multiplexer)

CWDM consists of 18 different wavelength channels spaced 20 nm apart from 1270nm to 1610nm. CWDM supports fewer channels than DWDM because it is compact and cost-effective, making it an ideal solution for short range communication. The main advantage of CWDM system is its low cost, which is reflected in filters and lasers. The wide wavelength interval of 20nm demands low technical requirement for laser and simplified structure of optical multiplexer/demultiplexer for CWDM. With simplified structure and improved yield, the cost is reduced.

DWDM (Dense Wavelength Division Multiplexer)

The channel spacing of DWDM is 1.6/0.8/0.4 nm (200GHz/100 GHz/50 GHz), much narrower than that of CWDM. Compared with CWDM, DWDM has dense wavelength spacing and can support 8 to 160 wavelengths on one optic fiber, very sui for long-haul transmission. Combined with EDFA, DWDM system can work within a range of thousands of kilometers.

CCWDM (Compact Coarse Wavelength Division Multiplexer)

CCWDM is the mini version of CWDM. It's a WDM technology based on TFF(Thin Film Filter), with the same working principle with CWDM. The difference is that CCWDM adopts free space technology, with its package size considerably reduced, lower insertion loss and better uniformity. It can replace CWDM products and be applied in telecom, enterprise network, PON, CATV, etc.

FWDM (Filter Wavelength Division Multiplexing)

FDWM is based on mature thin film filter technology. Filter-type WDM can combine or separate light of different wavelengths within a relatively wide wavelength range, and is widely used in EDFA (Erbium-doped Optical Amplifier), Raman amplifiers and WDM networks.LWDM (Local Area Network Wavelength Division Multiplexing)

LWDM is LAN-WDM technology based on ethernet channel, with channel spacing at 200 - 800GHz, a range between DWDM (100GHz, 50GHz) and CWDM (about 3THz). LWDM adopts the 12 wavelengths from 1269nm to 1332nm in the O-band range (1260nm - 1360nm), with wavelength intervals at 4nm (1269.23, 1273.54, 1277.89, 1282.26, 1286.66, 1291.1, 1295.56, 1300.05, 1304.58, 1309.14, 1313.73, 1318.35nm). The working wavelength of LWDM is located near zero dispersion with small dispersion and good stability. LWDM can support 12-wave 25G to boost capacity while economizing optical fiber.

Guilin GLSUN Science and Tech Group Co., Ltd as a key member of high-tech enterprises of China National Torch Plan, specializes in high level semiconductor laser diode chips development, production and packaging, focus on both Cloud Data Center and Telecom Networking Inter-connectivity. With widely production portfolio, our products including DFB LD chips, TO-CAN, high data rate passive optical devices and modules, function modules, monitoring and system protection equipment, etc.