Millimeter-wave Optical Transmission Links and Key Optical Modules

With the continuous development of optical communication technology, millimeter-wave optical transmission links are receiving increasing attention. Due to the high frequency of the millimeter-wave band, traditional cable transmission methods have many disadvantages, such as large size, high loss, heavy weight, and poor anti-interference capability. These bottlenecks largely limit high-frequency, long-distance applications. Fiber-optic transmission of millimeter-wave signals can overcome many of the defects of cable transmission and has become the optimal choice for high-frequency, long-distance transmission.

The typical block diagram of a millimeter-wave optical link is shown in Figure 1. 

For an external modulated optical link, the system's signal gain can be expressed as

i_B represents the DC photocurrent received by the photodetector, Z_out is the output load, is the electro-optic modulation response of the electro-optic modulator, and Z_in is the input impedance of the electro-optic modulator.

The link consists of a low-noise high-power laser module, a thin-film lithium niobate modulator module, optical fiber, and a millimeter-wave optical receiving module. The laser module has an output power greater than 60 mW and a relative intensity noise below -160 dBc/Hz; the electro-optic modulator module has a bandwidth greater than 50 GHz and a half-wave voltage better than 3 V; the photodetector module has a bandwidth greater than 50 GHz.

Figure 2 is the product family developed by our team, which can be flexibly applied to millimeter-wave optical transmission links, millimeter-wave fiber delay lines, and millimeter-wave radio altimeters.

DFB laser

TFLN modulator

photodetector

If you have any technical questions regarding link design or device applications, please feel free to contact us.