Optical receivers converts optical signals to the electrical signal and amplifies it if necessary. What are the applications of fiber optic receivers and where they are used in an optical communication network?
Fiber optic receivers are classified into two categories – digital and analog. Digital receivers detect the input optical signal, amplify the digital photocurrent, and reshape the signal to produce an undistorted output electrical signal. Analog receivers on the other hand detect the input optical signal and amplify the generated photocurrent.
For low-data-rate applications, PIN diodes and high impedance amplifiers are generally used. Receiver sensitivities are maximized by using large load resistors in the photodiode circuit. For moderate-data-rate applications, PIN diodes and either high impedance amplifiers with smaller load resistances or transimpedance amplifiers are used. For high-data-rate applications, PINs or APDs (Avalanche Photodiodes) are used with transimpedance amplifiers. APDs are rarely used in low- or moderate-data-rate applications unless receivers with extremely low sensitivities are required.
For each digital application, the receiver will generally contain a low-pass filter. The pass-band of the filter depends on the data rate of the application. The filter is used to smooth the amplified signal to remove some of the high frequency noise before the signal is further processed. The digital receiver generally contains a comparator, which reshapes the amplified electrical signal to remove any distortions introduced in the transmission process. There are some cases where the receivers may also contain clock recovery circuitry, which retimes the output electrical signal as well.
Optical receivers are used in a fiber optic network link. Telecommunication networks made of optical fibers requires a receiver to convert the incoming optical signals to electrical signals. An optical receiver is used at the ends of a link.
Fiber optic receivers are used in optical networks to convert optical signals back to electrical signals. An optical receiver essentially contains a detector to receive optical signals, a low noise amplifier and the circuits required to produce electrical output.
Applications of fiber optic receiver include Computer to Peripheral Links, Computer Monitor Links, Digital Cross Connect Links, Modems and Multiplexers, Suitable for Tempest Systems and Industrial Control Links.