Light detection and ranging (LiDAR) technology has recently been attracting considerable attention, but it is still difficult to achieve distributed reflectivity sensing and vibration detection simultaneously at high speed. To tackle this issue, we develop a new LiDAR configuration by extending fiber-optic correlation-domain reflectometry to the spatial system and demonstrate its fundamental operations. We experimentally show that the random accessibility unique to this configuration enables high-speed measurement of the vibration frequency and the position of a mirror oscillating at up to 100 kHz. This LiDAR may be applicable to visualization of flow velocity distributions, especially to distributed detection of turbulence, which induces vibration of dust particles in air.

No abstract

Optical correlation-domain reflectometry (OCDR), which is known as one of the fiber-optic techniques for distributed reflectivity sensing, conventionally included an acousto-optic modulator, a reference path, and erbium-doped fiber amplifiers in its setup. In this work, by removing all of these components simultaneously, we develop a super-simplified configuration of OCDR, which consists of a light source and a photodetector only. We experimentally show that this system can still perform distributed reflectivity sensing with a moderate signal-to-noise ratio, which will boost the portability and cost efficiency of the OCDR technology.

In simplified optical correlation-domain reflectometry (OCDR) without the use of an electrical spectrum analyzer (ESA), the noise floor of the reflectivity distribution is distorted in long-range measurement, which sometimes causes significant errors in the distributed reflectivity measurement. Herein, we experimentally analyze the distorted noise floor by high-speed ESA-free OCDR and clarify the origin of the noise floor. Then we show that this noise floor can be compensated by appropriate filtering. Consequently, distributed reflectivity measurement over a 1.1 km long sensing fiber is properly performed at a repetition rate of 100 Hz.

We experimentally analyze the distorted noise floor peculiar to the kilometer-order range distributed reflectivity measurement by high-speed optical correlation-domain reflectometry. We also show that this noise floor can be compensated by appropriate filtering.