Fourier domain mode-locked opto-electronic oscillator with a diode-tuned bandpass filter

Abstract

We report what we believe to be the first Fourier domain mode-locked (FDML) opto-electronic oscillator (OEO) without using a tunable signal source to implement, such as a tunable laser or a tunable microwave source as described in the previous reports. We designed and fabricated a tunable microwave filter with individually packaged microwave components, in which a low cost diode-tuned phase shifter was used to rapidly tune the filter center frequency. We successfully realized Fourier domain mode-locking of an OEO using the diode-tuned filter and obtained linearly chirped microwave signals around 9 GHz with a chirp rate of 36 MHz/µs and a frequency tuning range of 0.4 GHz, which can be extended to 142 MHz/µs and 1.56 GHz, respectively, with a filter circuit using chip sized components. We found, for the first time to the best of authors’ knowledge, that the phase noise of FDML OEO’s delayed self-heterodyne signal is an excellent indicator for mode-locking frequency optimization, which had a “U” shape dependence on the detuning of the mode-locking frequency with a locking range of over 40 Hz. We also investigated harmonic mode-locking of the FDML up to 5th harmonics and achieved a chirp rate of 180 MHz/µs using the tunable filter of individually packaged components. Compared with the previous FDML OEO’s implemented with tunable signal sources, our diode tuned FDML OEO has the advantages of low cost, compact size, excellent frequency tuning linearity, easy implemention and immunity to laser frequency drift and noise for achieving better frequency repeatability and lower phase noise.

Optoelectronic Oscillator for Arbitrary Microwave Waveform Generation

“…The stability of the generated arbitrary waveform largely depends on the wavelength stability of the laser source, the response and Ref. [20] Diode-tuned electrical phase shifter 0.4…”

“…As mentioned before, there are two implementation schemes for the FDML OEO. The methods proposed in [9] and [20] belong to the first one using frequency scanning electrical filters, while others belong to the second one using MPFs. For the methods using an MPF constructed via a wavelength scanning optical arbitrary waveform, the LCMW with low phase noise is generated by converting the wavelength scanning optical waveform to the electrical domain with the help of a frequency-scanning OEO based on FDML.…”

“…Note that most of the methods mentioned above only focus on how to realize different FDML OEOs based on different designs for generating single-chirp LCMWs [12]- [15], dual-chirp LCMWs [16]- [18], and frequency-multiplied LCMWs [12], [17], [19]. Few works focused on the improvements in terms of cost, size, and performance until an FDML OEO without using a tunable signal source was proposed in [20]. All in all, either a frequency-scanning electrical bandpass filter or a frequency-scanning MPF constructed by a wavelength scanning optical waveform is needed for the realization of an FDML OEO.…”

Photonic Generation of Wideband Chirped Microwave Waveforms

“…One key challenge in implementing a frequency-scanning BPF based on microwave photonics is the complicated structure and low energy efficiency due to OE and EO conversions involved. Recently, an FDML OEO using a diode-tuned bandpass filter was reported, which features a simplified system and low power consumption [86].…”

Implementing competence-based kindergarten teacher education in China : a case study of Hubei University of Arts and Science

“…Optoelectronic oscillator (OEO) exudes an inherent advantage in generating low phase noise signals [11][12][13][14][15] since the first prototype exposed by S. Yao and L. Maleki [16]. Especially, recently novel optoelectronic oscillators are emerged to expand the generated waveform styles and performance for various application scenario [17][18][19][20][21][22][23][24][25][26]. Fourier domain mode-locked OEO (FDML-OEO) that directly generates a broadband signal from the OEO cavity breaks the mode construction time [27], which is discovered as a potential application method for wideband Radar system.…”