Fig. 1. Schematic and microscopic image of an HSRL with BCB confinement layer. Square and rectangular sections are electrically isolated by a 20 μm isolation trench.

Fig. 2. (a) Output powers coupled into a tapered single-mode fiber versus IFP at fixed ISQ of 0, 5, 10, and 15 mA. (b) Lasing spectrum. (c) Detailed spectrum around dominant lasing mode at IFP=48  mA and ISQ=10  mA showing single-mode operation with an SMSR of 46 dB, for an HSRL with a=15  μm, d=2  μm, and L=300  μm.

Fig. 3. Lasing spectra versus different injection currents of (a) IFP as ISQ=10  mA and (b) ISQ as IFP=45  mA. Dominant mode wavelengths and SMSRs as functions of (c) IFP as ISQ=10  mA and (d) ISQ as IFP=45  mA, respectively, for HRSL with a=15  μm, d=2  μm, and L=300  μm.

Fig. 4. Normalized RF spectrum of the delayed self-heterodyne interference signal of lasing mode and Lorentzian fit to the measurement data, for the HSRL as ISQ=10  mA and IFP=50  mA.

Fig. 5. Small signal modulation responses of the HSRL with a=15  μm, d=2  μm, and L=300  μm at (a) IFP=15, 25, 35, 50 mA and ISQ=10  mA and (b) ISQ=5, 10, 15 mA and IFP=45  mA. (c) Resonance frequency versus square root of the injection current above threshold and (d) corresponding damping factors versus fR2 with variation of IFP at ISQ=10  mA.

Fig. 6. Experimental setup for measuring the relative intensity noise characteristics for the HSRL. SMF, single-mode fiber; PD, photodetector; DMM, digital multimeter; ESA, electrical spectrum analyzer.

Fig. 7. Measured laser RIN with the variation of (a) IFP as ISQ=10  mA and (b) ISQ as IFP=45  mA, respectively, for the HSRL with a=15  μm, d=2  μm, and L=300  μm.

Fig. 8. (a) Resonance frequency versus square root of the injection current above threshold and (b) damping factor versus fR2 with variation of IFP at ISQ=10  mA extracted from RIN measurements.