fiber optcial circulator Manufacturers

Fluorescence imaging has been widely used in biomedical imaging and clinical intraoperative navigation. When fluorescence propagates in biological media, absorption attenuation and scattering disturbance will cause fluorescence energy loss and signal-to-noise ratio decrease, respectively. Generally speaking, the degree of absorption loss determines whether we can "see", and the number of scattered photons determines whether we can "see clearly". In addition, the autofluorescence of some biomolecules and signal light are collected by the imaging system and eventually become the background of the image. Therefore, for biofluorescence imaging, scientists are trying to find a perfect imaging window with low photon absorption and sufficient light scattering.

Optical coherence tomography is a low-loss, high-resolution, non-invasive medical imaging technology developed in the early 1990s. It combines optical technology with ultrasensitive detectors. Using modern computer image processing, OCT fills the gap in resolution and imaging depth between microscopes and ultrasound imaging. The imaging resolution of OCT is about 10~15 μm, which is clearer than that of intravascular ultrasound (IVUS), but OCT cannot image through blood. Compared with IVUS, its tissue penetration ability is lower, and the imaging depth is limited to 1-2mm.

For panda and bowtie PM fibers, due to non-ideal coupling conditions, external stress on the fiber, and defects in the fiber, the polarization direction of part of the light will shift to the orthogonal direction, reducing the output extinction ratio.

Single-frequency lasers based on Er3+-doped or Er3+/Yb3+ co-doped gain fibers mainly work in the 1.5 μm band (C-band: 1530-1565 nm) and part of the L-band (1565-1625 nm). Its wavelength is in the C window of optical fiber communication, which makes the 1.5 μm band single-frequency fiber laser with narrow linewidth and low noise characteristics very important in coherent optical communication. It is used in high-resolution sensing, optical frequency domain reflectometer , laser radar and other fields also have a wide range of applications.

Optical fiber is the abbreviation of optical fiber, and its structure is shown in the figure: the inner layer is the core, which has a high refractive index, and is used to transmit light; the middle layer is the cladding, and the refractive index is low, forming a total reflection condition with the core; the outermost The layer is a protective layer to protect the optical fiber.

Erbium-doped fiber amplifier (EDFA, that is, an optical signal amplifier with erbium ion Er3 + doped in the core of the signal passing through) is the first optical amplifier developed by the University of Southampton in the UK in 1985. It is the greatest optical amplifier in optical fiber communication. One of the inventions. Erbium-doped fiber is an optical fiber doped with a small amount of rare earth element erbium (Er) ions in a quartz fiber, and it is the core of an erbium-doped fiber amplifier. Since the late 1980s, the research work of erbium-doped fiber amplifiers has continuously made major breakthroughs. WDM technology has greatly increased the capacity of optical fiber communications. Become the most widely used optical amplifier device in current optical fiber communication.