Fig. 1. Device diagram and schematic diagram of broadband OPA. (a) Broadband OPA device diagram; (b) schematic of broadband OPA

Fig. 2. Schematic of broadband BHD

Fig. 3. Noise performance and CMRR of broadband BHD. (a) Equivalent noise power spectra; (b) CMRR

Fig. 4. Experimental setup diagram of broadband squeezed light

Fig. 5. Noise power spectra of broadband squeezed light. (a) Noise power spectra when the central frequency is 30 MHz, and the relative phase between local light and signal light is in a scanning state (RBW is 30 kHz, and VBW is 30 Hz); (b) noise power spectra of 1-200 MHz, and the relative phase between local light and signal light is in a locked state (RBW is 300 kHz, and VBW is 150 Hz)