Photonic integrated circuits

A phontonic integrated circuit, comprising:

• a first optical coupler;
• a first waveguide operably coupled to said first optical coupler for propagating light to and from said first optical coupler;
• a second waveguide operably coupled to said first optical coupler for propagating light to and from said first optical coupler;
• a third waveguide having a first end operably coupled to said first optical coupler and a second end operably coupled to said first optical coupler, said third waveguide for propagating light received at said first end from said first optical coupler to said second end and back into said first coupler, and for propagating light received at said second end from said optical coupler to said first end and back into said first coupler;
• a fourth waveguide for propagating primarily a first mode of light and integrally formed with said third waveguide, said forth waveguide having at least one lateral taper formed therein for moving light between said third waveguide and said fourth waveguide, said first mode of light having a different index of refraction than light propagating in said third waveguide;
• a gain region integrally formed with said fourth waveguide for amplifying light propagating in said fourth waveguide;
• and
• a second optical coupler integrally formed with said third waveguide for transmitting a control signal into said third waveguide.

A photonic detector device, comprising:

• a first waveguide for guiding primarily a first mode of light;
• a second waveguide having a gain region formed therein, said second waveguide for guiding primarily a second mode of light and positioned vertically relative to said first waveguide, wherein said first mode of light has an effective index of refraction different from that of said second mode of light;
• a third waveguide for guiding primarily a third mode of light, said third waveguide positioned vertically relative to said second waveguide and separated from said first waveguide by said second waveguide, wherein said third mode of light has an effective index of refraction different from said second mode of light, and wherein said third waveguide and said second waveguide have a first taper formed therein, said first taper for guiding said first mode of light substantially between said first waveguide and said second waveguide, and wherein said third waveguide has a second taper formed therein for guiding said second mode of light between said second waveguide and said third waveguide;
• at least one further waveguide for guiding primarily a fourth mode of light, said further waveguide positioned vertically relative to said third waveguide and separated from said second waveguide by said third waveguide, wherein said further waveguide has a lateral taper formed therein for guiding said third mode of light between said third waveguide and said further waveguide and wherein said fourth mode of light has an effective index of refraction different from that of said third mode of light;
• and
• a photo-detector for detecting light propagating in said further waveguide, said photo-detector positioned vertically relative to said further waveguide and being separated from said second waveguide by said further waveguide.

A photonic integrated circuit, comprising:

• a first waveguide for guiding primarily a first mode of light having a plurality of wavelengths therein;
• a second waveguide for guiding primarily a second mode of light, said second waveguide having a gain region formed therein for amplifying light propagating therein, said second waveguide positioned vertically relative to said first waveguide and having a taper region formed therein for moving light between said first waveguide and said second waveguide, said second mode of light having a different index of refraction from said first mode of light
• a one to many optical coupler operably formed with said first waveguide;
• a first array of waveguides operably formed to said one to many optical coupler, each waveguide of said array of waveguides having a different length, wherein each of the plurality of wavelengths propagating in said first waveguide is propagates out of said one to many optical coupler onto one of said waveguides in said array of waveguides;
• a many to many optical coupler operably formed with said array of waveguides;
• and
• a second array of waveguides operably coupled to an output of said many to many optical coupler, wherein each waveguide of said second array of waveguides has a mode of light propagating therein and has a further waveguide positioned vertically relative thereto having a different mode of light propagating therein and having a taper formed therein for moving light between waveguides, each said further waveguide having a photodetector positioned vertically relative thereto for detecting light propagating in said further waveguide.

A photonic integrated circuit, comprising:

• a first photonic device comprising at least a first waveguide having a first mode of light propagating therein;
• a second photonic device comprising at least a second waveguide having a second mode of light propagating therein;
• and
• at least a third waveguide with said first and second waveguide, said at least third waveguide having a third mode of light propagating therein,
• wherein said first mode of light, said second mode of light, and said third mode of light have different effective indices of refraction.

A photonic integrated circuit, comprising:

• a first waveguide having a first mode of light propagating therein, said first waveguide comprised in a first photonic device;
• a second waveguide having a second mode of light propagating therein, said second waveguide comprised in a second photonic device;
• at least a third waveguide having a third mode of light propagating therein,
• wherein light is coupled between said first waveguide and said third waveguide, and between said third waveguide and said second waveguide, and
• said first, second, and third mode of light have different effective indices of refraction.

A photonic integrated circuit, comprising:

• a first photonic device having at least a first waveguide with substantially one mode of light propagating therein, said first waveguide communicating light with a second waveguide having a second mode of light propagating therein, said first and second modes of light being different;
• and
• a second photonic device having a third waveguide with substantially a third mode of light propagating therein, said third waveguide communicating light with a fourth waveguide having a fourth mode of light propagating therein, said third and fourth modes of light being different;
• wherein said first and second photonic device are formed on the same substrate and light from said first photonic device is communicated to said second photonic device.

A laser, comprising:

• a first waveguide having a first mode of light propagating therein;
• a second waveguide vertically positioned above said first waveguide and having a second mode of light propagating therein, said second waveguide having a gain region formed therein and having a taper section for communicating light between said first waveguide and said second waveguide;
• a barrier region formed above said second waveguide, said barrier region forming a ridge along the length of said second waveguide;
• a first grating region formed in said barrier region on a first side of said ridge;
• and
• a second grating region formed in said barrier region of a second side of said ridge, wherein said first grating region and second grating region reflect primarily one frequency of light,
• wherein said first and second modes of light have different effective indices of refraction.