What Is The OXC?

OXC, the full name is optical cross-connect.

Like ROADM, OXC is also an optical transmission device that can exchange optical signals between different optical paths.
The concept of OXC actually existed as early as around 2000. In a sense, ROADM is a special implementation of OXC, and OXC includes ROADM.
From the perspective of traditional architecture, OXC is composed of optical cross-connect matrix, input interface, output interface, management control unit and other modules. The optical cross-connect matrix is the core of OXC. The so-called matrix is actually a "box" with any internal ports interconnected in pairs.
We will explain with the architecture of Huawei's OXC equipment.

The OXC equipment is mainly composed of optical circuit boards, optical backplanes and optical tributary boards.
Generally speaking, each slot of the circuit board corresponds to one direction. After the optical signal enters, it is "disassembled" into N wavelength signals through WSS (Wavelength Selective Switch).
Earlier WSS switches used MEMS mechanical architecture. This structure has a high failure rate and poor reliability. Later, it evolved into the LCoS (liquid crystal on silicon) solution, which natively supports the Flexi-Grid function, supports variable channel widths and super channels, and has significantly higher reliability than MEMS.
In principle, the LCoS solution uses phase-controlled wavelength selection, no mechanical vibration, no optical amplification for upper and lower waves, and a direction dimension of up to 32 dimensions, achieving super large crossover capacity and lower power consumption.
The wavelength optical signal passes through the optical connector and enters the optical backplane from the optical circuit board.
Optical backplane is an important difference between OXC and ROADM, and has a high technical content. It is equivalent to printing many optical fibers on a piece of paper to realize optical connection.

The optical backplane provides support for large switching capacity and nanosecond delay.
After the wavelength optical signal comes out of the optical backplane, it enters the optical tributary board, and an N×M WSS is constructed by adding a level of LCoS crystal plane adjustment.