Fig. 1. Equivalent circuit model of the photodiode and transimpedance amplifier circuit.

Fig. 2. Circuit schematic. Where, GND is ground. Rf=R6=3  kΩ, R4=3  kΩ, R1=100  Ω, R9=50  Ω, R3=1  kΩ, C3=1  nF, C7=0.5  pF, C9=0.5  pF, C6=10  pF, L4=330  μH, L2=100  μH, L1, and L3 are chip beads. The 7805 and 7905 are power conversion modules, which can convert 15 and −15  V into 5 and −5  V.

Fig. 3. Gain curve of the circuit. The gain peak is at about 82 MHz, and the intersection is −3  dB for the gain and 129 MHz for the frequency.

Fig. 4. Circuit input noise curve IEq versus frequency.

Fig. 5. Calculated relative output power gain versus frequency. From bottom to top, the curves are the calculated relative electronics noise and output noise power when the optical input powers are 0.5, 1, 2, 4, 8, and 16 mW, respectively.

Fig. 6. Measured noise power of the laser with a different power. From the bottom curve to top, the lowest black curve is the background noise of the spectrum analyzer, and the blue one is the electronics noise of the photoelectric detector. The other curves are the output noise power with different laser powers.

Table 1. Parameters of the Photodetector with Different Input Optical Powers