Optical modulation and amplification apparatus, optical module, optical network unit, and optical communication system

An optical module, comprising:

• an electric absorption modulator comprising a first waveguide and a second waveguide that are serially connected in a transmission direction of injection light, wherein the first waveguide and the second waveguide each comprise a ridge waveguide structure;
• a semiconductor optical amplifier electrically isolated from the electric absorption modulator, wherein:
• the electric absorption modulator and the semiconductor optical amplifier share a same substrate and use a same multi-layer material structure disposed on the substrate,
• the multi-layer material structure comprises, from bottom to top, a first quantum well configured to modulate the injection light, an electron blocking layer, a second quantum well configured to amplify the injection light, and an upper separate confinement layer, wherein the electron blocking layer is configured to block a current applied to the second quantum well from flowing into the first quantum well,
• a first difference between an extinction ratio corresponding to a transverse electric (TE) mode and an extinction ratio corresponding to a transverse magnetic (TM) mode in the electric absorption modulator is dependent on a thickness of the upper separate confinement layer and a stress of the first quantum well, and the first difference is less than or equal to a first preset value, and
• a second difference between a modal gain corresponding to the TE mode and a modal gain corresponding to the TM mode in the semiconductor optical amplifier is dependent on the thickness of the upper separate confinement layer and a stress of the second quantum well, and the second difference is less than or equal to a second preset value;
• and
• a driver configured to drive the electric absorption modulator and the semiconductor optical amplifier to modulate and amplify the injection light.

A method of operating an optical modulation and amplification apparatus comprising:

• an electric absorption modulator comprising a first waveguide and a second waveguide that are serially connected in a transmission direction of injection light, wherein the first waveguide and the second waveguide each comprise a ridge waveguide structure;
• and a semiconductor optical amplifier electrically isolated from the electric absorption modulator, wherein the electric absorption modulator and the semiconductor optical amplifier share a same substrate and use a same multi-layer material structure disposed on the substrate, the multi-layer material structure comprises, from bottom to top, a first quantum well configured to modulate the injection light, an electron blocking layer, a second quantum well configured to amplify the injection light, and an upper separate confinement layer, wherein the electron blocking layer is configured to block a current applied to the second quantum well from flowing into the first quantum well, a first difference between an extinction ratio corresponding to a transverse electric (TE) mode and an extinction ratio corresponding to a transverse magnetic (TM) mode in the electric absorption modulator is dependent on a thickness of the upper separate confinement layer and a stress of the first quantum well, and the first difference is less than or equal to a first preset value, a second difference between a modal gain corresponding to the TE mode and a modal gain corresponding to the TM mode in the semiconductor optical amplifier is dependent on the thickness of the upper separate confinement layer and a stress of the second quantum well, and the second difference is less than or equal to a second preset value, the method comprising:
• providing the injection light to the electric absorption modulator;
• and
• amplifying the injection light using the semiconductor optical amplifier.