An optical power detection apparatus, comprising: a modulator configured to modulate an optical signal of a light source to output a modulated optical signal; an optical power detection device comprising: an optical splitter configured to receive the modulated optical signal and split the modulated optical signal into a first optical signal and a second optical signal at a preset fixed proportion, the second optical signal being coupled into an output port of the optical power detection device as a main output signal; a photocell connected to an output end of the optical splitter, the photocell being configured to receive the first optical signal output by the optical splitter and convert the first optical signal into a current signal; an electrical amplification module connected to an output end of the photocell, the electrical amplification module being configured to receive the current signal output by the photocell, convert the current signal into a voltage signal, and perform gain processing on and then output the voltage signal; and a micro-shield configured to encapsulate the photocell and the electrical amplification module; characterized in that the optical power detection apparatus further comprises a phase bias control unit connected to the optical power detection device and the modulator, and configured to receive a voltage signal output by the optical power detection device and to adjust a phase bias working point of the modulator. a modulator configured to modulate an optical signal of a light source to output a modulated optical signal; an optical power detection device comprising: an optical splitter configured to receive the modulated optical signal and split the modulated optical signal into a first optical signal and a second optical signal at a preset fixed proportion, the second optical signal being coupled into an output port of the optical power detection device as a main output signal; a photocell connected to an output end of the optical splitter, the photocell being configured to receive the first optical signal output by the optical splitter and convert the first optical signal into a current signal; an electrical amplification module connected to an output end of the photocell, the electrical amplification module being configured to receive the current signal output by the photocell, convert the current signal into a voltage signal, and perform gain processing on and then output the voltage signal; and a micro-shield configured to encapsulate the photocell and the electrical amplification module; characterized in that the optical power detection apparatus further comprises a phase bias control unit connected to the optical power detection device and the modulator, and configured to receive a voltage signal output by the optical power detection device and to adjust a phase bias working point of the modulator. an optical splitter configured to receive the modulated optical signal and split the modulated optical signal into a first optical signal and a second optical signal at a preset fixed proportion, the second optical signal being coupled into an output port of the optical power detection device as a main output signal; a photocell connected to an output end of the optical splitter, the photocell being configured to receive the first optical signal output by the optical splitter and convert the first optical signal into a current signal; an electrical amplification module connected to an output end of the photocell, the electrical amplification module being configured to receive the current signal output by the photocell, convert the current signal into a voltage signal, and perform gain processing on and then output the voltage signal; and a micro-shield configured to encapsulate the photocell and the electrical amplification module; characterized in that the optical power detection apparatus further comprises a phase bias control unit connected to the optical power detection device and the modulator, and configured to receive a voltage signal output by the optical power detection device and to adjust a phase bias working point of the modulator.