Frequency-chirped silicon photonic lasers systems
AssigneeOpenLight Photonics, Inc.
InventorsJohn Parker, Molly Piels, Erik Johan Norberg
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Abstract
A frequency-chirped integrated silicon-photonic laser may be provided with separate gain and phase-tuning sections in the laser cavity, one or two wavelength filters forming part of the reflective structures defining the cavity, and electro-optic and optionally thermo-optic intra-cavity and filter phase tuners. The electro-optic phase tuners may be driven with synchronized voltage waveforms, at amplitudes determined, based on measurements of the laser output power and chirp, to achieve mode-hop-free frequency chirping with a target chirp amplitude. The waveforms may be predistorted to improve chirp linearity.
Claims23
A chirped laser system comprising:
- a laser comprising an optical gain section, an electro-optic intra-cavity phase tuner, and a tunable optical wavelength filter comprising an electro-optic filter phase tuner;
- photonic monitoring circuitry comprising:
- a monitor photodiode to measure a photocurrent indicative of an output power of laser light generated by the laser;
- and
- an interferometric wavelength monitor to measure a photocurrent indicative of a change in frequency of the laser light;
- and
- electronic control circuitry coupled to the photonic monitoring circuitry and the laser, the electronic control circuitry configured to chirp the frequency of the laser light by applying synchronized voltage waveforms to the electro-optic intra-cavity phase tuner and the electro-optic filter phase tuner, wherein:
- a ratio of amplitudes of the synchronized voltage waveforms applied to electro-optic intra-cavity phase tuner and the electro-optic filter phase tuner is set to an inverse of a ratio of tuning efficiencies of the electro-optic intra-cavity phase tuner and the electro-optic filter phase tuner as determined from the output power measured over a chirp period, and
- the amplitudes of the synchronized voltage waveforms applied to electro-optic intra-cavity phase tuner and the electro-optic filter phase tuner are scaled to achieve a target chirp amplitude as determined from the change in frequency of the laser light measured over the chirp period.
A method of calibrating a chirped laser comprising an optical gain section, an electro-optic intra-cavity phase tuner, and a tunable optical wavelength filter comprising an electro-optic filter phase tuner, the method comprising:
- applying a triangular voltage waveform to the electro-optic intra-cavity phase tuner and measuring a number of negative spikes in laser output power to determine a tuning efficiency of the electro-optic intra-cavity phase tuner;
- applying the triangular voltage waveform to the electro-optic filter phase tuner and measuring a number of negative spikes in laser output power to determine a tuning efficiency of the electro-optic filter phase tuner;
- applying, to the electro-optic intra-cavity phase tuner and the electro-optic filter phase tuner, synchronized triangular voltage waveforms with an amplitude ratio inverse to a ratio of the tuning efficiencies of the electro-optic intra-cavity phase tuner and the electro-optic filter phase tuner, and measuring a chirp of laser light output by the chirped laser;
- adjusting the synchronized triangular voltage waveforms applied to the electro-optic intra-cavity phase tuner and the electro-optic filter phase tuner in amplitude until a target chirp amplitude is reached;
- and
- saving the adjusted amplitudes of the synchronized triangular waveforms to memory.
A method of operating a chirped laser comprising an optical gain section, an electro-optic intra-cavity phase tuner, and a tunable optical wavelength filter comprising an electro-optic filter phase tuner, the method comprising:
- applying a gain current to the optical gain section to generate laser light at an output of the chirped laser;
- and
- chirping a frequency of the laser light by applying synchronized voltage waveforms to the electro-optic intra-cavity phase tuner and the electro-optic filter phase tuner, wherein:
- a ratio of amplitudes of the synchronized voltage waveforms is set to an inverse of a calibrated ratio of tuning efficiencies of the electro-optic intra-cavity phase tuner and the electro-optic filter phase tuner, and
- the amplitudes of the synchronized voltage waveforms are scaled to achieve a target chirp amplitude.
Dependencies are inferred from the claim text.