Silicon-based tunable filter, tunable laser and optical module

A tunable laser, comprising a semiconductor optical amplifier and a silicon photonic integrated chip, wherein a first coupler, a phase regulator, and a tunable filter are provided on the silicon photonic integrated chip, and the tunable filter comprises a flat-top band-pass filter structure, a Mach-Zehnder interferometry structure, and one micro ring resonation structure which are cascaded,

• the Mach-Zehnder interferometry structure has asymmetric tunable phase shift arms, the micro ring resonation structure comprises one tunable ring waveguide and two straight waveguides, the two straight waveguides are respectively coupled to the tunable ring waveguide to act as an Input end and a Drop end of the micro ring resonation structure, and the micro ring resonation structure is cascaded with the flat-top band-pass filter structure and the Mach-Zehnder interferometry structure through the Input end and/or the Drop end,
• a gain light emitted by the semiconductor optical amplifier is coupled to the silicon photonic integrated chip through the first coupler, and then the interference effect of the Mach-Zehnder interferometry structure and the resonance effect of the micro ring resonation structure are superimposed on the gain light, and the filtering effect of the flat-top band-pass filter structure is also act on the gain light, which forms a tunable target wavelength light to output,
• the phase regulator is configured to regulate a phase of the gain light,
• wherein the semiconductor optical amplifier is a reflective semiconductor optical amplifier, the tunable filter also comprises a ring mirror, the ring mirror comprises a 2×2 coupler and a ring waveguide, the ring waveguide is respectively connected to two ports on one side of the 2×2 coupler, and two ports on the other side of the 2×2 coupler are respectively an input port and an output port,
• one, two, or three of the flat-top band-pass filter structure, the Mach-Zehnder interferometry structure, and the micro ring resonation structure are cascaded on the ring waveguide and/or on the input port of the 2×2 coupler, and the output port of the 2×2 coupler is a laser output port for outputting a laser light.

A tunable laser, comprising a semiconductor optical amplifier and a silicon photonic integrated chip, the semiconductor optical amplifier is configured to provide a laser gain, the semiconductor optical amplifier has a first end surface and a second end surface opposite to each other, the second end surface is configured to be coupled to the silicon photonic integrated chip, and the first end surface acts as a cavity surface of a laser resonating cavity, wherein the silicon photonic integrated chip comprises:

• a first coupler, configured to couple the semiconductor optical amplifier and the silicon photonic integrated chip;
• a phase regulator, configured to regulate the phase of a laser light;
• and
• a tunable filter, configured to filter a resonant light in the laser resonating cavity to obtain a single-peak narrowband laser output, wherein another cavity surface of the laser resonating cavity is disposed on the tunable filter, and the first coupler and the phase regulator are located in the laser resonating cavity,
• the tunable filter comprises a flat-top band-pass filter structure, a Mach-Zehnder interferometry structure, and one micro ring resonation structure which are cascaded, the Mach-Zehnder interferometry structure has asymmetric tunable phase shift arms, the micro ring resonation structure comprises one tunable ring waveguide and two straight waveguides, the two straight waveguides are respectively coupled to the tunable ring waveguide to act as an Input end and a Drop end of the micro ring resonation structure, and the micro ring resonation structure is cascaded with the flat-top band-pass filter structure and the Mach-Zehnder interferometry structure through the Input end and/or the Drop end,
• wherein
• the semiconductor optical amplifier is a reflective semiconductor optical amplifier,
• the tunable filter also comprises a ring mirror, the ring mirror comprises a 2×2 coupler and a ring waveguide, the ring waveguide is respectively connected to two ports on one side of the 2×2 coupler, and two ports on the other side of the 2×2 coupler are respectively an input port and an output port, one, two, or three of the flat-top band-pass filter structure, the Mach-Zehnder interferometry structure, and the micro ring resonation structure are cascaded on the ring waveguide and/or on the input port of the 2×2 coupler,
• the ring mirror acts as the end surface of the laser resonating cavity which is disposed on the tunable filter, and the output port of the 2×2 coupler is a laser output port for outputting the laser light.