Portable optical frequency standard based on sealed gas-filled hollow-core fiber using a novel encapsulation technique

A portable stand-alone optical frequency standard based on a gas-filled hollow-core photonic crystal fiber is developed to stabilize a fiber laser to the 13C2H2 P(16) (ν1 + ν3) transition at 1542 nm using saturated absorption. A novel encapsulation technique is developed to permanently seal the hollow-core fiber with easy light coupling, showing negligible pressure increase over two months. The locked laser shows a fractional frequency instability below 8 × 10−12 for an averaging time up to 104 s. The lock-point repeatability over one month is 2.6 × 10−11, corresponding to a standard deviation of 5.3 kHz. The system is also assembled in a more compact and easy-to-use configuration (Plug&Play), showing comparable performance with previously published work. The real portability of this technology is proved by shipping the system to a collaborating laboratory, showing unchanged performance after the return.