Fast initialization digital automatic optical power control circuit for laser driver

Abstract

The invention discloses a fast initializing digital automatic optical power control circuit for a laser driver, which relates to the field of laser drivers. The circuit includes ASP, DSP, BIAS? DAC, MOD? DAC, BIAS? CTRL, MOD? CTRL and LDPD components, ASP connected with DSP, DSP and BIAS respectively? DAC, MOD? DAC, MOD? CTRL connected, BIAS? DAC and BIAS? CTRL connected, MOD? DAC and MOD? CTRL connected, BIAS? CTRL, MOD? Both CTRL and ASP are connected with LDPD components, and LDPD components are composed of laser LD and backlight tube PD. The invention can complete the initialization of the automatic optical power control within 1200ns, adopts the advanced digital signal processing method for precise control, only implements the initialization during the period when the burst enable is valid, and satisfies the requirement of the burst mode function.

Description

technical field [0001] The invention relates to the field of laser drivers, in particular to a fast initialization digital automatic optical power control circuit for the laser driver. Background technique [0002] Compared with the traditional LDD, the LDD (Laser Diode Driver, laser driver) used in PON (Passive Optical Network, Passive Optical Network) needs to work in burst mode, so it also has some special requirements in terms of performance. When the LDD works in the burst mode, the APC (AutoPower Control, automatic optical power control) circuit of the LDD is required to be able to complete the initialization in the three shortest burst packets of 1.25Gbps (Gigabitpersecond, gigabit per second) data, and the initialization time is about 1200ns. If the LDD uses the traditional initialization APC circuit, see figure 1 As shown, LD (LaserDiode, laser) and PD (PhotoDiode, backlight tube) together form the LDPD component. After the modulation current Imod output by the LD...

AI Technical Summary

Problems solved by technology

If the LDD uses the traditional initialization APC circuit, see figure 1 As shown, LD (LaserDiode, laser) and PD (PhotoDiode, backlight tube) together form the LDPD component. After the modulation current Imod output by the LDD passes through the LDPD component, the backlight current Ipd will generate a glitch signal associated with the modulation current Imod, which seriously affects The initialization circuit works normally

If the glitch interference is eliminated through the filter capacitor, the stabilization time of the circuit will be greatly increased, resulting in a substantial increase in the initialization time, which does not meet the requirements of the system

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