Chip-based laser resonator device for highly coherent laser generation

摘要

A highly-coherent chip-based laser generating system includes a disk resonator incorporating a wedge structure fabricated from a silicon dioxide layer of a chip. The disk resonator is operable to generate a highly-coherent laser from a low-coherence optical pump input provided at an optical power level as low as 60 μW. The disk resonator is fabricated with sub-micron cavity size control that allows generation of a highly-coherent laser using a controllable Stimulated Brillouin Scattering process that includes matching of a cavity free-spectral-range to a Brillouin shift frequency in silica. While providing several advantages due to fabrication on a chip, the highly-coherent laser produced by the disk resonator may feature a Schawlow-Townes noise level as low as 0.06 Hz2/Hz (measured with the coherent laser at a power level of about 400 μW) and a technical noise that is at least 30 dB lower than the low-coherence optical pump input.

主权项

1. A laser source comprising:
(a) a pump laser source and an optical fiber arranged to launch pump laser power to propagate along the optical fiber past a tapered segment thereof; and (b) a semiconductor oxide disk optical resonator positioned on a semiconductor substrate so as to enable optical coupling of at least a portion of the pump laser power from the optical fiber into the disk optical resonator, wherein: (c) the disk optical resonator rests on a circumscribed, flat-topped protrusion from a surface of the substrate; (d) the pump laser source and the disk optical resonator are arranged so that a selected optical frequency of the pump laser power substantially coincides with an optical frequency of a resonant optical mode of the disk optical resonator; (e) the disk optical resonator is arranged with a substantially frusto-conical outer circumferential surface, characterized by a slope angle greater than about 27°, so as to exhibit a Q-factor greater than about 107 at the pump laser optical frequency; and (f) the disk optical resonator is arranged so as to exhibit a free spectral range that substantially coincides with an optical frequency of a stimulated Brillouin gain spectrum of the semiconductor oxide disk optical resonator, so that the portion of the pump laser power coupled into the disk optical resonator, with the pump laser power above a pump laser power threshold level, results in stimulated Brillouin laser oscillation in the disk optical resonator.