TUOLIMA

Optical Coupler

Fiber optical couplers are optical devices that connect three or more fiber ends, dividing one input between two or more outputs, or combining two or more inputs into one output.   The cable type accepted by fiber optic couplers can be could be single mode or multimode.  Single mode describes an optical fiber that will allow only one mode to propagate. The fiber has a very small core diameter of approximately 8 μm. It permits signal transmission at extremely high bandwidth and allows very long transmission distances.  Multimode describes a fiber optic cable, which supports the propagation of multiple modes. Multimode fiber may have a typical core diameter of 50 to 100 μm with a refractive index that is graded or stepped. It allows the use of inexpensive LED light sources and connector alignment and coupling is less critical than single mode fiber. Distances of transmission and transmission bandwidth are less than with single mode fiber due to dispersion.  Choices for coupler type include single window, dual window, or wideband.  Single window couplers are designed for a single wavelength with a narrow wavelength window.  Dual wavelength couplers are designed for two wavelengths with a wide wavelength window for each.  Wideband couplers are designed for a single wavelength with a wider wavelength window.  Wavelength choices for fiber optic couplers include 633 nm, 830 nm, 1060 nm, 1300 nm, and 1550 nm.

Optical Receiver

Fiber optic receivers are instruments that convert light into electrical signals. Sometimes they are also called optical nodes. They contain a photo diode semiconductor, signal conditioning circuitry, and an amplifier. Fiber optic receivers use three types of photo diodes: positive-negative (PN) junctions, positive-intrinsic-negative (PIN) photo diodes, and avalanche photo diodes (APD). The signal received is transmitted to RF network.

Fiber Optic Cable (Outdoor)

Fiber optic cable (outdoor) is composed of many fibers enclosed in protective coverings and strength members. Fiber can be single mode or multi mode. Common features for fiber optic cable include polarization maintaining, graded index, and metalization. A polarization maintaining cable has fiber that maintains the polarization of light that enters it. A graded index fiber optic cable has optical fiber in which the refractive index of the core is in the form of a parabolic curve, decreasing toward the cladding. Metalized fibers are coated with metals for increased temperature resistance, soldering, and harsh environments. An important environmental parameter to consider is the operating temperature.