High-efficiency InGaAs QW distributed Bragg reflector laser with curved grating for squeezed light generation

A high-efficiency InGaAs quantum-well curved distributed Bragg reflector (DBR) laser was designed for squeezed light generation and fabricated using a selective-area quantum-well disordering technique to reduce absorption loss in the DBR grating region. Single-mode lasing with side-mode suppression ratio of 50 dB was obtained, and an external differential quantum efficiency as high as 0.71 was achieved under continuous-wave operation. Using balanced detection technique, the laser intensity noise relative to the standard quantum limit (SQL) was measured. Ultra-low noise characteristic of 0.8 dB below the standard quantum limit was achieved by wideband constant-current driving of the laser. This is the first demonstration of single-mode squeezed light generation by a monolithic semiconductor laser at room temperature.