A low noise optically tunable optoelectronic oscillator (OEO) scheme which uses a 1000 finesse Fabry-Perot etalon as the mode selector is demonstrated. The dependency of input optical frequency on RF frequency is theoretically analyzed and experimentally shown. The etalon-based OEO is compared with the standard OEO with RF filter and the results show higher RF frequency stability and lower phase noise. A single optical side band modulation technique is also used to improve the spectral purity and the results are compared with the double side band modulation technique. Low noise operation of an optically tunable OEO is achieved by using optical single side band modulation.