Broadband arbitrary wavelength multichannel laser source

A multi-channel laser source, comprising:

• a bus waveguide coupled, at an output end of the bus waveguide, to an output of the multi-channel laser source;
• a first semiconductor optical amplifier;
• a first back mirror;
• a first wavelength-dependent coupler having a first resonant wavelength;
• a second semiconductor optical amplifier;
• a second back mirror;
• a second wavelength-dependent coupler having a second resonant wavelength, different from the first resonant wavelength;
• a third wavelength-dependent coupler having a third resonant wavelength, different from the first and second resonant wavelengths;
• and
• an output mirror at the output end of the bus waveguide,
• the first semiconductor optical amplifier including inhomogeneously broadened gain material and comprising:
• a first end coupled to the first back mirror, and
• a second end,
• the first wavelength-dependent coupler comprising:
• a channel port connected to the second end of the first semiconductor optical amplifier;
• a bus output connected to a first portion of the bus waveguide;
• a bus input, connected to a second portion of the bus waveguide more distant from the output end of the bus waveguide than the first portion of the bus waveguide;
• and
• a fourth port,
• the third wavelength-dependent coupler comprising:
• a channel port connected to the fourth port of the first wavelength-dependent coupler;
• a bus input, connected to the first portion of the bus waveguide;
• and
• a bus output, connected to a third portion of the bus waveguide nearer the output end of the bus waveguide than the first portion of the bus waveguide,
• the second semiconductor optical amplifier being coupled to the second portion of the bus waveguide through the second wavelength-dependent coupler,
• the first wavelength-dependent coupler being nearer to the output end of the bus waveguide than the second wavelength-dependent coupler,
• the first wavelength-dependent coupler being configured to transmit light, at the second resonant wavelength, from the bus input of the first wavelength-dependent coupler to the bus output of the first wavelength-dependent coupler, and
• the output mirror having a first reflectance at the first resonant wavelength and a second reflectance at the second resonant wavelength, the first reflectance differing from the second reflectance by no more than 10%.