An example of lithium niobate modulation application - carrier suppression single sideband generation

    Lithium niobate electro-optical modulator is made using the electro-optical effect of lithium niobate crystal and integrated optical technology. It has the advantages of high response speed (~ 100GHz), low half-wave voltage (less than 5V), small volume, and so on. It can realize high-speed digital signal and analog signal modulation and is widely used in high-speed optical communication, microwave photons, optical fiber sensing, quantum communication, and other fields.
     It is the most common technique in microwave photons to produce carrier suppressed single-sideband using lithium niobate IQ modulator. The optical SSB technology of carrier suppression can effectively suppress the high-order nonlinear effect and dispersion, improve the RoF link's performance, and have an actual application in the generation of the high-frequency microwave signal. Let's introduce the generation principle and technology of one download wave suppression single sideband.

   1. IQ modulator
The IQ modulator consists of three Mach Zehnder (MZ) interferometers: the mother MZ and two sub MZ, providing two RF input ports (1-2 in the figure) and three pairs of bias control ports (3-8 in the model).

 2. Principle of single sideband generation with carrier suppression
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 3. Test
   The test is carried out by using a conquering photoelectric carrier suppression SSB modulator. Kg-inbox-SSB-1550 series suppression carrier SSB modulation unit is a highly integrated product with independent intellectual property rights of conquering photoelectrically. The instrument unit integrates DFB laser, Mach Zehnder dual parallel modulator, bias controller, RF driver, phase shifter, and other necessary components and realizes the generation of suppression carrier SSB through driver circuit and program control. Not only It is convenient for users and dramatically improves the reliability of the MZ intensity modulator. The schematic system diagram is as follows:

The product physical figure is as follows:

  The center wavelength of the laser is 1550.1nm and the RF signal is 10GHz

 It can be seen that the suppression ratio of the carrier to the right band is 23dB, and that of the left band to the right band is 29dB.