The invention discloses a preparation method and a structure of a photonic integrated device, and the method comprises the steps: sequentially dividing a substrate into a front modulator region, a rear modulator region, a front
grating region, a
gain region and a rear
grating region, and growing a first
active layer after manufacturing a selected region epitaxial
mask pattern in the
gain region, the method comprises the following steps of: growing a first
active layer in a front modulator region after
mask etching operation, growing a second
active layer in a front modulator region after
mask etching operation, growing a third active layer in a
grating region after mask
etching operation, finally performing grating manufacturing, and completing manufacturing of a cladding layer, an
electric contact layer, an inverted table shallow
ridge waveguide structure, an electric isolation trench and an
electrode. According to the method, integration of multiple materials is achieved through one-time selective area epitaxial growth and one-time
butt joint growth, the
material growth frequency is reduced, and the manufacturing cost is saved; the
gain region and the rear modulator region realize forbidden
band width offset through selective region
epitaxial material growth, and multi-
wavelength tuning and efficient modulation are realized through
fluorescence wavelength difference design of each region, so that a solution can be provided for integration of a wide-
wavelength tunable laser and a double-electro-absorption modulator.