Transmitter photonic integrated circuit (TxPIC) chips

A monolithic transmitter photonic integrated circuit (TxPIC) chip comprising:

• an array of semiconductor laser sources, each formed in an optical waveguide of an array of optical waveguides and operating at a different wavelength and providing a respective light output;
• an array of electro-optic modulators integrated on said chip, one each in an optical waveguide of said waveguide array to receive the respective light output of a laser source to provide a modulated output comprising a channel signal, all of said channel signals together representative of a plurality of designated wavelengths on a predetermined wavelength grid;
• an arrayed waveguide grating integrated on said chip, said arrayed waveguide grating coupled to each of said optical waveguides of said waveguide array to receive said channel signal from said modulators and combined into a multiplexed signal on at least one optical output waveguide from said chip;
• and
• isolation means formed in said chip between said arrays of laser sources and electro-optic modulators and said one output waveguide to prevent unguided light emanating from said arrays from optically interfering with said multiplexed signal in said one output waveguide.

A multiple wavelength division multiplexing optical transmitter system comprising:

• at least two monolithic transmitter photonic integrated circuit (TxPIC) chips each comprising:
• an array of N laser sources, each formed in an optical waveguide of an array of optical waveguides and each having a respective light output and operating at a different wavelength and together forming a first grid of wavelengths on a predetermined wavelength grid;
• an array of N electro-optic modulators integrated on said chips, one each in an optical waveguide of said waveguide array to receive the respective light output of a laser source and provide a modulated output comprising a channel signal;
• a combiner integrated on said chip, said combiner coupled to each of said optical waveguides to receive a channel signal from each said N modulators and combine N channel signals into a combined channel signal of all N channel signals on an optical waveguide output from each of said at least two chips;
• and
• tuning means applied to at least one of said monolithic transmitter photonic integrated circuit (TxPIC) chips to change said first grid of wavelengths on a predetermined wavelength grid of said chip to a second grid of wavelengths on the predetermined wavelength grid so that said at least two chips together form two times N signal channels on the predetermined grid.

A multiple wavelength division multiplexing optical transmitter system comprising:

• at least two monolithic transmitter photonic integrated circuit (TxPIC) chips each comprising:
• an array of N laser sources, each formed in an optical waveguide of an array of optical waveguides and each having a respective light output and operating at a different wavelength and together forming a first grid of wavelengths on a predetermined wavelength grid;
• each of said N laser sources modulated to provide a modulated output comprising a channel signal;
• a combiner integrated on said chip, said combiner coupled to each of said optical waveguides to receive a channel signal from each said N modulators and combine N channel signals into a combined channel signal of all N channel signals on an optical waveguide output from each of said at least two chips;
• and
• tuning means applied to at least one of said monolithic transmitter photonic integrated circuit (TxPIC) chips to change said first grid of wavelengths on a predetermined wavelength grid of said chip to a second grid of wavelengths on the predetermined wavelength grid so that said at least two chips together form two times N signal channels on the predetermined grid.

A monolithic photonic integrated circuit (PIC) chip comprising:

• an array of light sources, each formed in an optical waveguide of an array of optical waveguides and operating at a different wavelength forming a grid of wavelengths on a predetermined wavelength grid and each providing a respective light output comprising a channel signal;
• an optical combiner integrated on said chip, said combiner having an input for coupling to each of said optical waveguides to receive said channel signals and combine them as a combined channel signal;
• and
• a plurality of vernier output waveguides formed on the chip from an output of said combiner, an optimum output waveguide selected of said vernier output waveguides providing an optimum overall wavelength grid response relative to said grid of wavelengths.

A method of providing a monolithic photonic integrated circuit (PIC) chip having a plurality of different wavelength channels forming a grid of wavelengths on a predetermined wavelength grid, comprising the steps of:

• providing a plurality of integrated light sources on the chip having different wavelengths of operation and providing a plurality of on-chip light channels on the predetermined wavelength grid;
• combining with an optical combiner the light channels into a single output light signal;
• providing the single output light signal to a plurality of vernier outputs from the optical combiner;
• and
• selecting the optical combiner vernier output having a best wavelength grid response for taking the single output light signal off-chip.

A monolithic transmitter photonic integrated circuit (TxPIC) chip comprising:

• an array of laser sources, each formed in an optical waveguide of an array of optical waveguides and operating at a different wavelength and providing a respective light output;
• an array of Mach-Zehnder modulators integrated on said chip, one each in an optical waveguide of said waveguide array to receive the respective light output of a laser source and provide a modulated output comprising a channel signal;
• and
• an optical combiner integrated on said chip, said combiner having an input for coupling to each of said optical waveguides to receive said channel signals and combine them as a combined signal on at least one optical output waveguide from said chip to a chip output facet.

A monolithic transmitter photonic integrated circuit (TxPIC) chip comprising:

• an array of DFB laser sources, each formed in an optical waveguide of an array of optical waveguides and operating at a different wavelength and providing a respective light output;
• an array of electro-absorption modulators (EAMs) integrated on said chip, one each in an optical waveguide of said waveguide array to receive the respective light output of a DFB laser source and provide a modulated output comprising a channel signal, all of said channel signals representative of a wavelength on a predetermined wavelength grid;
• an arrayed waveguide grating (AWG) integrated on said chip, said arrayed waveguide grating coupled to each of said optical waveguides of said waveguide array to receive said channel signal from each said modulators and combine them as a multiplexed channel signal on an optical waveguide output from said chip;
• an operational bias for each of said electro-absorption modulators (EAMs) chosen such that its band edge wavelength is close to a wavelength of operation of its corresponding DFB laser source so that a small modulating electrical field across the modulator produces a large change in modulator light absorption.

A monolithic transmitter photonic integrated circuit (TxPIC) chip comprising:

• an array of laser sources, each formed in an optical waveguide of an array of optical waveguides and operating at a different predetermined wavelength together forming a grid of wavelengths on a predetermined wavelength grid and each providing a respective light output comprising a channel signal;
• a laser driver circuit connected to each on-chip laser source for driving each of said laser sources to provide said respective light output at a predetermined wavelength on said grid;
• a tone signal superimposed on each channel signal having a frequency different from a frequency of any other tone signals so that each laser source can be individually identified;
• an optical combiner integrated on said chip, said combiner having an input for coupling to each of said optical waveguides to receive said light outputs and combine them as a combined optical signal for output from the chip;
• and
• an optical feedback circuit coupled to receive a small portion of the chip signal output for stabilization of each of said light sources, said feedback circuit comprising:
• a photodetector for converting the optical signal output portion into an electrical signal;
• a power splitter to divide the electrical signal into a plurality of separate paths, the number of paths totaling the number of laser sources on said chip;
• a tone filter provide in each path to filter a tone signal from all other tone signals so that each filter provides a corresponding laser source light output of one of said laser sources;
• a circuit to receive each of said laser source light outputs to determined its wavelength of operation;
• and
• said circuit providing a correction signal to each of said laser driver circuits to change its corresponding laser driver bias or applied current to correct for the wavelength of operation of a laser source that is not operating at a desired predetermined wavelength.

A monolithic transmitter photonic integrated circuit (TxPIC) chip comprising:

• an array of laser sources, each formed in an optical waveguide of an array of optical waveguides and operating at a different wavelength together forming a grid of wavelengths on a predetermined wavelength grid and each providing a respective light output comprising a channel signal;
• an optical combiner integrated on said chip, said combiner having an input for coupling to each of said optical waveguides to receive said light outputs and combine them as a combined optical signal for output from the chip;
• an optical feedback circuit coupled to receive a small tapped portion of the chip signal output for wavelength stabilization of each of said light sources;
• and
• optical means in a path of the chip signal output beyond the tapped portion of the chip signal output to extinguish or attenuate the chip signal output during a period of wavelength stabilization of said light sources.

A monolithic transmitter photonic integrated circuit (TxPIC) chip system comprising:

• an array of laser sources, each formed in an optical waveguide of an array of optical waveguides and operating at a different wavelength forming a grid of wavelengths on a predetermined wavelength grid and each providing a respective light output;
• an array of electro-optic modulators integrated on said chip, one each in an optical waveguide of said waveguide array to receive the respective light output of a laser source and provide a modulated output comprising a channel signal;
• and
• an optical combiner integrated on said chip, said combiner having an input for coupling to each of said optical waveguides to receive the channel signals from said electro-optic modulators and combine them as a combined optical signal for output from the chip;
• a submount for receiving and flip-chip mounting of the chip;
• a plurality integrated circuit control chips mounted on said submount and electrically coupled to said laser sources and said modulators for electrical operation of the same.

A monolithic receiver/transmitter photonic integrated circuit (Rx/TxPIC) chip system comprising:

• a submount on which the chip is mounted;
• at least one Rx/TxPIC chip comprising:
• an input coupled to an integrated decombiner for receiving an optical signal comprising a plurality of combined optical channel signals of different wavelengths together forming a grid of wavelengths on a predetermined wavelength grid;
• an array of integrated photodetectors on said chip and optically coupled to receive a plurality of decombined optical channel signals from said optical decombiner for conversion into first electrical channel signals;
• an array of laser sources, each formed in an optical waveguide of an array of optical waveguides and operating at a different wavelength together forming a grid of wavelengths on a predetermined wavelength grid and each providing a respective light output comprising a channel signal;
• an array of electro-optic modulators integrated on said chip, one each in an optical waveguide of said waveguide array to receive the respective light output of a laser source and coupled to receive second electrical channel signals and provide a modulated output comprising a channel signal;
• and
• an optical combiner integrated on said chip, said combiner having an input for coupling to each of said optical waveguides to receive the channel signals from said electro-optic modulators and combine them as a combined optical signal to an output;
• and
• a plurality of integrated circuit control chips mounted on said submount and electrically coupled to said photodetectors, laser sources and said modulators for electrical operation thereof.

A monolithic optical-electrical-optical (OEO) regeneration semiconductor chip for handing and processing a group of optical channel signals comprising:

• an optical multiplexed signal input and an optical multiplexed signal output;
• an integrated optical decombiner optically coupled to receive an optical multiplexed signal at said signal input and demultiplex said multiplexed signal into a plurality of optical channel signals;
• an integrated array of integrated photodetectors, each optically coupled to receive a respective channel signal and convert the same to an electrical channel signal;
• an electrical output port on said chip that receives said electrical channel signals from said photodetectors;
• an integrated array of modulated laser sources on said chip;
• an electrical input port on said chip that receives electrical channel signals that respectively modulate one of said modulated laser sources and produce a plurality of optical channel signals;
• and
• an integrated optical combiner optical coupled to received said optical channel signals and combine them into a single optical multiplexed signal which is provided to said optical multiplexed signal output.