Power control system of double-closed-loop laser tube

Abstract

The invention discloses a power control system of a double-closed-loop laser tube. The power control system of the double close-loop laser tube comprises a modulation current control circuit, a bias current control circuit and a driving circuit. The modulation current control circuit comprises a first comparing circuit and a first adjusting circuit, wherein the first comparing circuit generates a binary first comparing signal based on a real output signal and a first aim signal value; the first adjusting circuit is used for generating modulation current according to the binary first comparing signal, and the modulation current is conveyed to the driving circuit. The bias current control circuit comprises a second comparing circuit and a second adjusting circuit; and the modulation current control circuit and the bias current control circuit further comprise clock control circuits. The power control device of the closed-loop laser tube avoids influence on a main data channel caused by the modulation loop.

Description

technical field [0001] The invention relates to digital optical communication, more specifically, a double closed-loop laser tube power control system configured for laser diodes. Background technique [0002] In digital optical data communication, laser diode (laser tube) is the core device of electro-optical conversion in optical communication, and its luminous efficiency and stability of luminous characteristics have a crucial impact on the entire communication link. How to ensure that the laser diode maintains a constant output optical power under environmental conditions, and how to ensure that there is a sufficient power difference between the output high level and the output low level, is the key to ensuring the reliability of the communication link. [0003] Such as figure 1 Shown is the relationship curve between the laser tube output optical power (Pout) and the driving current (Ilaser). Among them, P1, P2, P3 and P4 are the relationship curves between the output...

AI Technical Summary

Problems solved by technology

However, this solution adopts a bit-to-bit (BIT-TO-BIT) control mode, that is, to control each transmission mode. In order to realize BIT-TO-BIT power control, the amplifier 166 and the comparators 153 and 156 need high-speed To meet the code rate requirements of optical communication, the requirements for these devices are relatively high, and they need to be high-speed and high-precision devices; in addition, in order to ensure APC precision, two high-speed and high-precision comparators 153, 156 need to ensure sufficient comparison precision , the high-speed transimpedance amplifier 166 needs to have a large enough bandwidth to consume a large amount of power

Moreover, the above-mentioned circuit adjusts the bias current and modulation current when the device is sending the data signal. Therefore, if the clock Ck adopts a clock frequency that has nothing to do with the transmitted data, the APC is likely to alias unwanted frequencies into the transmitted data. On the other hand, if the Ck signal is extracted from the transmitted data to meet specific requirements, a built-in high-speed clock recovery signal is required, which adds a large additional power consumption

Moreover, due to the limitation of the loop bandwidth in this circuit, a low-frequency ripple signal with a frequency close to the APC loop bandwidth will be superimposed on the transmitted data, which further increases additional noise

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