Narrow linewidth laser system based on semiconductor lasers

Quantum technologies such as quantum information processing, quantum metrology and sensing rely on single-frequency, low-noise lasers in their core operations. Further development, scalability and commercialization of quantum technologies will be heavily dependent on the availability of affordable single-frequency lasers on a variety of application-specific wavelengths. Quantum applications manifest strict requirements for laser sources in terms of central wavelength, linewidth, long-term stability, polarization extinction ratio, side-mode suppression ratio, etc. Semiconductor lasers offer numerous significant advantages for quantum technology applications. Their broad wavelength coverage is made possible through bandgap engineering of light emitting active area. Intrinsic versatility of semiconductor lasers’ emission coupled with frequency control, which is implemented either through monolithic on-chip gratings such as in distributed Bragg reflector (DBR) and distributed feedback lasers (DFB), or external cavity optical elements, makes semiconductor lasers a very promising laser platform to address the acute need for small-size, mass-produced singlefrequency lasers. Modulight presents the development and characterization results of two narrow-linewidth laser systems incorporating a combination of in-house manufactured single-frequency lasers and internally developed low-noise driving electronics. The first laser system is designed for two-wavelength operation at cooling and repumping frequencies of Rb⁸⁷ D2 line utilizing near-IR 780.24 nm DBR lasers. Another system example includes frequency-doubled semiconductor laser in the green part of spectrum at 553 nm for Ba photoionization in trapped ion computing applications. Demonstrated exemplar platforms are viable and cost-effective tailorable alternatives to bulky and expensive Ti:Sapphire and legacy dye lasers, thus facilitating the advancement of quantum industry into real-world applications.