Optoelectronic oscillator using an ultra-high finesse Fabry-Perot etalon as a photonic filter for low phase noise at high oscillating frequencies

Abstract

A 100,000 finesse Fabry-Perot etalon with a 1.5 GHz free spectral range is used as a photonic filter in an optoelectorinc oscillator. The etalon acts as a ~15 kHz microwave filter to suppress spurious modes in a single loop OEO configuration. The etalon maintains its narrow filtering capability at harmonics of the FSR. Phase noise of the 10.5 GHz tone with 2 km of delay is measured at -120 dBc/Hz at 10 kHz offset. Oscillation as high as 54 GHz with 3 km of fiber delay is achieved while maintaining suppression of spurious modes below the noise floor of the measurement. Pound-Drever-Hall frequency stabilization of the laser frequency is used to reduce optical frequency noise and keep the laser frequency centered within the etalon resonance for long term operation of the OEO.

An opto‐electronic oscillator based on Fabry‐Perot stabilized dual‐wavelength fiber ring laser

“…The latter shows an output signal with potentially low phase‐noise. Figure 4D shows the phase noise measurement of such RF signal, where a phase noise of −100 dBc/Hz @10 kHz is observed, indicating a phase‐noise performance comparable to state‐of‐the‐art OEO methods 11–18 …”

“…In Radio‐over‐Fiber (RoF) systems, there are several photonic techniques used to generate microwave carriers, such as the heterodyne beating between two wavelengths generated by a DWFL 8–10 or from OEOs 11–18 . Because both the linewidth and phase‐noise of the photonically (or electrically) generated microwave signals are the key features for many applications, a comparison between the results obtained in this and in previous works is presented in Table 1.…”

“…Figure 4D shows the phase noise measurement of such RF signal, where a phase noise of À100 dBc/Hz @10 kHz is observed, indicating a phase-noise performance comparable to state-of-the-art OEO methods. [11][12][13][14][15][16][17][18] In Radio-over-Fiber (RoF) systems, there are several photonic techniques used to generate microwave carriers, such as the heterodyne beating between two wavelengths generated by a DWFL [8][9][10] or from OEOs. [11][12][13][14][15][16][17][18] Because both the linewidth and phase-noise of the photonically (or electrically) generated microwave signals are the key features for many applications, a comparison between the results obtained in this and in previous works is presented in Table 1.…”

“…When compared with Reference8, the present novel setup allows a linewidth reduction of $84.1% at full width at half maximum (FWHM) of the microwave carrier generated from the beat of the optical signals. While a number of works already reported dual-wavelength operation [8][9][10] or opto-electronic-oscillation, [11][12][13][14][15][16][17][18] the present paper reports the simultaneous employment of both technologies named as dual-wavelength fiber ring laser mutual-coupled to an opto-electronic oscillator (2-λ-OEO) in order to generate a narrow linewidth microwave carrier with a high extinction ratio and low phase-noise.…”

Opto-Electronic Oscillators for Micro- and Millimeter Wave Signal Generation

“…The dual-loop and multi-loop configurations [11][12][13][14], coupled OEO [15][16][17][18], injection-locked OEO [19][20][21][22], OEO with quality multiplier [23], and OEO with feedback loop [24] are some of the well-known configurations. Moreover, optical solutions are possible by adding components such as optical filters [25][26][27] and optical amplifiers [28,29] or by adjusting the optical link to achieve an optical gain [30]. These are already used to improve the stabilization of the OEO.…”