Investigations On Mode Modulation And Device Fabrication Of Vertical Cavity Surface Emitting Lasers

With the advantages of high reliability,low cost,long lifetime,small size,and high performance,vertical cavity surface emitting lasers(VCSELs)have a wide application market and are of common interest to both academia and industry.Due to the short cavity length,VCSELs possess dynamic single longitudinal mode properties;due to the large transverse dimensions,VCSELs usually exhibit multi-transverse mode characteristics.Multi-transverse mode VCSELs were the first VCSELs to be commercialized and have been widely used in short-range optical interconnects,smartphones,and LIDAR.The rapid development of downstream applications also continues to put new demands on VCSELs with single-mode,dual-wavelength and tunable characteristics.In this paper,we propose to use surface relief structure to increase the transverse limiting size of the device while limiting the transverse optical field to achieve stable control of single mode.Today's methods for simultaneous tunable dual-wavelength excitation are complex,either using complex external cavity structures or requiring more sophisticated sample structures.This makes it difficult and expensive to implement tunable dual-wavelength lasers,which greatly limits the application of tunable dual-wavelength lasers.To study this,the following innovative research work has been carried out in this paper around the mode tuning problem of VCSELs from two perspectives:transverse and longitudinal modes,respectively.1.By regulating the transverse mode of VCSEL to achieve single-base transverse mode laser output and develop VCSEL devices with output power greater than 2 m W at 80°C:a high-power VCSEL light source that can work stably in single mode at high temperature is designed,the oxide aperture is further expanded,and the transverse mode field is controlled by surface relief structure to achieve single-mode high power output with single-mode output power at 80°C The single-mode output power at 80°C is greater than 2 m W and the edge-mode rejection ratio is 29.2 d B,which is now reported as the best performance for single-mode VCSELs operating at high temperatures.2.Hollow-beam VCSEL devices were developed by modulating the transverse mode of the VCSEL to achieve single high-order mode laser output:for the first time,the hollow beam was achieved by using the oxidation aperture and surface relief to select a specific transverse mode of the VCSEL,and the maximum single-mode output power was 3.66 m W at room temperature and 2.53 m W at 80°C in the single-mode LP₂₁ mode,with a power drop of only The maximum single-mode output power is 3.66m W at room temperature and 2.53 m W at 80°C,with a power drop of only 30.8%.3.Vertical external cavity structure-based VCSEL longitudinal mode modulation:a compact dual-wavelength VECSEL device is proposed,and the gain-cavity mode mismatch design is based on the variation of the gain spectrum with pump power,and the mismatch wavelength is 24 nm.The wavelength can be switched between 950 nm and 1000 nm,and the wavelength interval is nearly 50 nm.4.The effect of the active region on the longitudinal mode modulation is explored:a new compact structure of synchronous tunable dual-wavelength laser is designed,proposing to use the quantum-limited gain structure of indium-rich clusters as the active region,and with the ultra-wide and flat-top gain characteristics generated by this complex structure,only a single gain chip and a single grating are needed to realize the synchronous output of dual-wavelength with equal power,simplifying the structure of the dual-wavelength laser and obtaining the maximum output power of This simplifies the dual-wavelength laser structure and achieves a 974 nm/(969.1-977.9 nm)simultaneous dual-wavelength laser.