Application of rigid flex PCB in 5G optical module

What is an optical module?

The optical module is composed of optoelectronic devices, functional circuits, and optical interfaces. The optoelectronic device includes two parts: transmitting and receiving.

To put it simply, the function of the optical module is to convert the electrical signal into an optical signal at the transmitting end. After being transmitted through the optical fiber, the receiving end converts the optical signal into an electrical signal.


Classified according to parameters:

Pluggability: hot-swappable and non-hot-swappable

Package form: SFP, GBIC, XFP, Xenpak, X2, 1X9, SFF, 200/3000pin, XPAK.

Transmission rate: The transmission rate refers to the number of bits transmitted per second, in Mb/s or Gb/s. Optical module products cover the following main rates: low rate, 100M, Gigabit, 2.5G, 4.25G, 4.9G, 6G, 8G, 10G and 40G.


5G optical module

The transmission rate of the optical module is a very important indicator to measure the performance of the optical module. In the 3G era, the maximum transmission rate of optical modules is generally below 5G/S; in the 4G era, the transmission rate of optical modules is generally around 5G-40G/S; however, in the 5G era, customers have much higher requirements on the transmission rate of optical modules. , The transmission rate of ordinary 5G optical modules can reach> 40g/s, and even some customers require the highest transmission to reach 200G/s. This undoubtedly brings great challenges to material vendors and circuit board manufacturers.

Therefore, some customers have taken a different approach and designed the circuit board of the optical module into a flexible and hard combined board, so that more components can be placed in the narrow optical module, thereby increasing the transmission speed; at the same time, the flexible and hard combined board can be used in 3D space. The inner three-dimensional folding is beneficial to the internal heat dissipation of the optical module, thereby making the transmission of the optical module more stable.

However, most of the optical module solutions using the rigid flex PCB are in the small-batch stage and have not been mass-produced. The biggest reason is that the rigid flex board has a high cost due to many processes. If the rigid flex PCB is adopted, the overall cost will undoubtedly be greatly increased.

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