RESUMO
A fully fibered microwave-optical source at 1.5 µm is studied experimentally. It is shown that the beat note between two orthogonally polarized modes of a distributed-feedback fiber laser can be efficiently stabilized using an optical phase-locked loop. The pump-power-induced birefringence serves as the actuator. Beat notes at 1 GHz and 10 GHz are successfully stabilized to a reference synthesizer, passing from the 3 kHz free-running linewidth to a stabilized sub-Hz linewidth, with a phase noise as low as -75 dBc/Hz at 100 Hz offset from the carrier. Such dual-frequency stabilized lasers could provide compact integrated components for RF and microwave photonics applications.
RESUMO
We realize a 1 W all-fibered polarized compact and robust laser source at 852 nm for laser cooling of cesium atoms. The architecture is based on the sum-frequency generation of 1540 and 1908 nm lasers, realized through a periodically poled lithium niobate waveguide with a conversion efficiency of 40%. A linewidth of 20 kHz is achieved with the development of a distributed feedback fiber laser at 1908 nm. The operation of this laser source is demonstrated on a focused ion beam (FIB) experiment based on cold cesium atoms.
RESUMO
We present a new structure for erbium-doped optical fibers [hole-assisted carbon-coated, (HACC)] that, combined with an appropriate choice of codopants in the core, strongly enhances their radiation tolerance. We built an erbium-doped fiber amplifier based on this HACC fiber and characterize its degradation under γ-ray doses up to 315 krad (SiO2) in the ON mode. The 31 dB amplifier is practically radiation insensitive, with a gain change of merely -2.2×10(-3) dB/krad. These performances authorize the use of HACC doped fibers and amplifiers for various applications in environments associated with today's missions (of doses up to 50 krad) and even for future space missions associated with higher dose constraints.