Drive circuit for laser

Abstract

The invention provides a drive circuit of a laser, which comprises a laser component and an LD drive; wherein, the laser component is connected with a bias current output terminal and a modulated current output terminal of the LD drive, and a bias current set terminal and a modulated current set terminal of the LD drive are connected with a drive current set chip which is connected with a singlechip MCU through an I<2>C communication interface; the singlechip is connected with a turn-off pin of the LD drive through an interface 2 of a second interface I / O to control drive and enable LDDDis, and is also connected with an external interface through a main I<2>C communication interface; the emission of the external interface enables TxDis and is connected with an interface 1 of a first interface I / O of the singlechip, the state of TxDis enabled by emission can be distinguished by the singlechip MCU through the interface 1 of the first interface I / O, and the state of the drive current set terminal of the drive current set chip is controlled according to the state of the TxDis enabled by emission. Therefore, wavelength shift of the laser is reduced to achieve the requirements for the stability of the wavelength of the laser when a DWDM system is applied.

Description

technical field [0001] The invention relates to a laser driving circuit in a dense wavelength division multiplexing DWDM data transmission system, in particular to a laser driving circuit. Background technique [0002] In a dense wavelength division multiplexing (DWDM) data transmission system, the channel spacing of optical signals of different wavelengths becomes smaller and smaller as the density of the multiplexed channels increases. In order to ensure that the lights of the mutual channels do not collide, the wavelength of the transmitting end needs to maintain high stability. For example, in a 100GHZ DWDM system, the interval between adjacent channels is only 0.8nm. The system supplier requires the emission wavelength to be between λc-0.1nm and λc+0.1nm, and the instantaneous wavelength when the laser is turned on and off is Within the range of λc-0.2nm~λc+0.2nm. The usual DWDM laser driver circuit such as figure 1 As shown, the laser assembly 10 integrates a laser ...

AI Technical Summary

Problems solved by technology

After testing, the wavelength of the laser has a large drift at this moment, and it exceeds the normal channel spacing range, which will affect adjacent channels and cause system confusion

Analyze this momentary situation. At the moment when the laser is turned on, a large amount of driving current flows through the laser diode LD11, causing the temperature of the laser to rise suddenly. However, due to the hysteresis of the temperature transmission to the thermistor, the TEC driving circuit cannot respond to this moment. Timely response to the temperature change will cause a large instantaneous wavelength drift, causing the system to work chaotically

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