Distortion Reduction Filters for Radio-on-Fiber System(<Special Section>Evolution of Microwave and Millimeter-Wave Photonics Technology)

概要

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Three distortion reduction filters for radio-on-fiber systems are proposed and evaluated from the standpoint of improvements in in-band third order intermodulation (IM3) components (spurious components), insertion loss, temperature stability and so on. The basic filter configuration includes optical comb filter, RF (radiowave frequency) comb filter, and RF dual band rejection filter (DBRF). Experiments are conducted at 2GHz band for frequency separation Δf=5MHz and 100MHz in the temperature range of -10℃ to +50℃. These filters can reduce IM3 components even in the saturation region, unlike conventional linearizers. An optical comb filter can reduce IM3 components more than 20dB and noise level around 10dB if its polarization controller is properly adjusted, but its insertion loss is large and stability against vibration is very poor. The proposed RF comb filter and RF-DBRF can reduce IM3 components by more than 20dB and noise level by more than 3dB. Their stability against vibration and temperature change is good, and insertion losses are 1-2dB for Δf=100MHz.
社団法人電子情報通信学会の論文
2007-02-01