| Raman fiber amplifier is a kind of optical amplifier, which can amplify signal light directly based on stimulated Raman scattering with high intensity pump in fiber. Through adjusting the power of multi-channel optical pump lasers with different wavelengths can amplify the power of wavelength division multiplexing (WDM) source, which have almost the same light power. In order to ensure that the WDM signal light power after amplifying is flat, it is important to measure the signal light power of each channel. It is necessary to demultiplex the WDM source first and make the demultiplexing light signal into current signal by using photoelectric detector. The preamplifier can convert current signal into voltage signal, which can recognized by electrical equipment easily. So, the value of each optical channel power can be measured.In this paper, a wavelength division multiplexing source detection module was designed and produced. The module used MSP430F1610 as micro controller unit. The MCU controls LTC2600 to output analog scanning voltage, which will be amplified by power amplifier. The amplified voltage can drive the fiber Fabry Perot tunable filter(FFP-TF). The change of driving voltage can control the FFP-TF to filter out the light waves of different wavelengths. Then the light waves can convert into photocurrent through the PIN diode. The photocurrent is difficult to detect due to the small value. Using preamplifier can convert the current signal into amplified voltage signal. Finally, the voltage can be sampled by Analog-to-Digital Converter, and the optical power value can be calculated by the corresponding relation.The dynamic range of modules is 20 db. After calibration by optical spectrum analyzer(OSA), the error between the measured value of detection module and the measured value of the optical spectrum analyzer is less than±0.5dB. The WDM source detection module provides accurate feedback for the realization of amplifying WDM source with flat gain. |
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