PLC Type WDM

CWDM transmission system generally uses uncooled lasers and optical amplifiers, and its cost is lower than that of DWDM. Therefore, CWDM Technology is suitable for short-distance, high bandwidth, access point intensive communication applications, mainly used in metropolitan area network convergence layer, access layer, private network, small city backbone layer.

DWDM is mainly used in Metro backbone layer and long-distance backbone network. Through the use of DFB wavelength stability control laser with refrigeration, erbium-doped fiber amplifier (EDFA), forward error correction (FEC) technology, dispersion compensation technology, ultra long-distance nonregenerative relay, ultra-large capacity transmission is realized.

Arrayed waveguide grating (AWG) is a kind of planar integrated waveguide (PLC) WDM device with multiplexing and demultiplexing functions. The principle of using AWG to realize WDM devices was first proposed by M.K. Smith in 1988. AWG has the function of focusing and dispersing at the same time. That is to say, the same wavelength of light can be focused on one point, and the focus of different wavelengths can be shifted by dispersion.

The performance of AWG is also closely dependent on temperature sensitivity or thermal stability. The change of temperature will cause the change of the refractive index of the material, which is called the thermooptical effect of the material. The change index of the material refractive index to the temperature didn't is called the term optical coefficient of the material. The change of temperature will cause the spectral shift of AWG and increase the insertion loss and crosstalk. Therefore, it is of great significance and practical value to reduce the sensitivity of AWG to temperature and realize the athermal operation of the device.