Numerical Study Of Optical Injection Locking Of Semiconductor Laser To Coherent Multimode Lasers

Optical injection locking is a widely used technique,which can synchronize the phase of low power laser with narrow linewidth to obtain high power narrow linewidth laser.This technique has been developed into a very mature technology,but in recent years,due to the development of multi-mode coherent optical source,using multi-mode coherent optical source as the master laser injecting semiconductor laser has become a new research hotspot,showing some new applications and new dynamics mechanism.Optical frequency comb is composed of a large number of modes with constant frequency interval and fixed relative phase.It is widely used in optical frequency measurement,microwave generation,optical communication and optical frequency synthesis.However,these applications may be affected by many redundant modes,so separating individual mode and amplifying it to a reasonable power level can greatly extend the application range of optical frequency comb.In addition,coherent multimode optical injection locking can also produce very rich nonlinear processes,and strong optical injection locking can broaden the spectrum or produce laser chaotic behavior.In this paper,multimode coherent optical injection locking is investigated using numerical simulation methods,the main works are:1.The noises of mode selection and amplification of optical frequency comb injection locking semiconductor laser are numerically studied where the noises include residual side modes and the excessive noises.The results show that excessive noises can be introduced through interference between residual side modes and resonance within Arnol’d tongues created by periodic forcing in the optical phase,which greatly reduces spectral purity.The dependences of residual side modes rejection and phase noise variance on the comb mode spacing,seeding power,linewidth enhancement factor and frequency detuning are also discussed,which can help the design and application of low-noise systems.2.Generating optical frequency comb using dual-frequency laser injection locking semiconductor laser is studied by numerical simulation.Due to the four-wave mixing effect in the active semiconductor gain medium,the beat-note frequency signal can be efficiently converted into an optical frequency comb.By locking in the relaxation oscillation and compensating the gain asymmetry,a low-noise Gaussian-like pulse can be obtained.The simulation also shows that by changing the beat-note frequency,seeding power,linewidth enhancement factor,frequency detuning and relaxation oscillation,the pulse train with pulse width below 30 ps and comb mode spacing at GHz can be generated.The optical injection locking technology can amplify the output optical power while broadening the spectrum,it can lay a good initial stage for the generation of optical frequency combs by multi-stage spectral broadening of dual-frequency lasers in nonlinear waveguides.