Abstract: A tunable comb generator may include a light source to generate an optical signal, an intensity modulator to modulate an intensity of the optical signal from the light source based on a RF drive signal, a frequency-locking loop (FLL) to maintain an optical frequency of the optical signal received from the intensity modulator at a target optical frequency corresponding to a resonance frequency of a periodic optical filter in the FLL, and an optoelectronic oscillator (OEO) loop. The OEO loop may include a photodetector to generate the RF drive signal based on the optical signal from the FLL, a tunable phase shifter to select a resonance frequency of the OEO loop corresponding to a harmonic of the resonance frequency of the periodic optical filter, and one or more phase modulators to generate an optical comb signal by modulating a portion of the optical signal from the FLL.

Abstract: Apparatus and methods demonstrate a chip-scale direct optical to RF link that frequency divides up to 120 GHz optical frequency combs to 10 GHz using harmonic multi-tone injection locking. The embodied invention links widely separated optical frequency combs in the millimeter wave regime (>120 GHz) or THz domain (100s of GHz to THz domain), e.g., microresonator-based frequency combs, which are currently outside of the photo-detection region, into the microwave domain (10s of GHz) where it can be easily photo-detected and controlled. The technique works as a perfect optical divider, using a mode-locked laser and optical injection locking as the technique to phase-lock both lasers.

Abstract: Apparatus and methods demonstrate a chip-scale direct optical to RF link that frequency divides up to 120 GHz optical frequency combs to 10 GHz using harmonic multi-tone injection locking. The embodied invention links widely separated optical frequency combs in the millimeter wave regime (>120 GHz) or THz domain (100s of GHz to THz domain), e.g., microresonator-based frequency combs, which are currently outside of the photo-detection region, into the microwave domain (10s of GHz) where it can be easily photo-detected and controlled. The technique works as a perfect optical divider, using a mode-locked laser and optical injection locking as the technique to phase-lock both lasers.

Abstract: A tunable comb generator may include a light source to generate an optical signal, an intensity modulator to modulate an intensity of the optical signal from the light source based on a RF drive signal, a frequency-locking loop (FLL) to maintain an optical frequency of the optical signal received from the intensity modulator at a target optical frequency corresponding to a resonance frequency of a periodic optical filter in the FLL, and an optoelectronic oscillator (OEO) loop. The OEO loop may include a photodetector to generate the RF drive signal based on the optical signal from the FLL, a tunable phase shifter to select a resonance frequency of the OEO loop corresponding to a harmonic of the resonance frequency of the periodic optical filter, and one or more phase modulators to generate an optical comb signal by modulating a portion of the optical signal from the FLL.

Abstract: A tunable electro-optic modulation (EOM) comb generator includes a frequency locking optoelectronic oscillator (OEO) loop including RF electrical components including a phase shifter (PS1), a splitter, and optical components including an intensity modulator (IM) coupled to receive light from a light source and to couple modulated light generated to a frequency locking loop including a frequency shifter, a first phase modulator (PM1), and a periodic optical filter (POF), such as an etalon or resonator. The POF is for optically filtering the OEO loop to generate an optical output and the splitter is for generating RF electrical outputs including at least one RF output coupled to an input of the IM and another RF output coupled to an EO comb including at least a phase modulator. The EO comb combines the optical output and the another RF output to generate a broadband optical frequency comb output.

Abstract: A tunable electro-optic modulation (EOM) comb generator includes a frequency locking optoelectronic oscillator (OEO) loop including RF electrical components including a phase shifter (PS1), a splitter, and optical components including an intensity modulator (IM) coupled to receive light from a light source and to couple modulated light generated to a frequency locking loop including a frequency shifter, a first phase modulator (PM1), and a periodic optical filter (POF), such as an etalon or resonator. The POF is for optically filtering the OEO loop to generate an optical output and the splitter is for generating RF electrical outputs including at least one RF output coupled to an input of the IM and another RF output coupled to an EO comb including at least a phase modulator. The EO comb combines the optical output and the another RF output to generate a broadband optical frequency comb output.