Differential mode-locked laser phase-locked loop

Abstract

The invention discloses a differential mode-locked laser phase-locked loop, comprising a phase discriminator, a proportional-integral loop filter, a differential loop filter module, a voltage-controlled oscillator, a photodetector and a band pass filter that are connected in sequence. The band pass filter is connected with the phase discriminator. The invention provides a scheme of multiple differential loop filter phase-locked loop. In the phase-locked loop, the two or more differential loop filters are used to compensate for the phase lag caused by a piezoelectric transducer and a high-voltage driver, thereby improving the upper limit of the bandwidth of the phase-locked loop by more than one order of magnitude, greatly expanding the improvement space for the phase-locked bandwidth whileensuring the stability of the phase-locked loop.

Description

Technical field [0001] The present invention relates to the field of electronic technology, in particular to a phase-locked loop of a differential mode-locked laser. Background technique [0002] Passively mode-locked lasers (MLL) have been widely used as ultrashort pulse laser sources in the fields of optical / RF frequency standard generation, photonic radar, optical communications, ultra-low noise microwave synthesis, precision time-frequency measurement and time-frequency distribution. These applications require the use of a phase-locked loop to lock the passive mode-locked laser to a high-stability optical or microwave frequency standard source, so that the phase and repetition frequency of the passive mode-locked laser can be locked to the high-stability frequency standard source through the phase-locked loop . [0003] The locked bandwidth of the phase-locked loop is defined as the corresponding system frequency when the open-loop gain amplitude of the phase-locked loop is 0d...

AI Technical Summary

Problems solved by technology

Therefore, the requirement for system stability makes the upper limit of the locking bandwidth of the phase-locked loop limit the improvement limit of the locking bandwidth

[0004] For a practical passive differential mode-locked laser PLL, the piezoelectric transducer and its high-voltage driver in the system have time delay and resonance characteristics, which introduce an additional phase lag in the loop, limiting the PLL's performance. bandwidth cap

In this case, due to the low upper limit of the PLL bandwidth, once the loop gain is increased so that the locked bandwidth is higher than the upper limit of the bandwidth, it will cause the PLL to oscillate or lose lock

Therefore, in a passive mode-locked laser phase-locked loop system with only proportional-integral loop filters, the phase lag introduced by its piezoelectric transducer and high-voltage driver limits the upper limit of its locking bandwidth, thereby limiting Potential of Phase Loop Locking Bandwidth to Improve Output Optical Pulse Signal Stability and Timing Jitter Performance

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