Dimitrios Mandridis

A Semiconductor-Based 10-GHz Optical Comb Source With Sub 3-fs Shot-Noise-Limited Timing Jitter and

In this work, a 10.287-GHz semiconductor-based harmonically mode-locked laser with 1000 finesse intracavity etalon is demonstrated. The timing jitter integrated from 1 Hz to 100 MHz (Nyquist) is 3 fs (14 fs). The optical linewidth is ~500 Hz and the optical frequency stability is <150 kHz over 30 s.

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A lidar technique employing temporally stretched, frequency chirped pulses from a 20 MHz mode locked laser is presented. Sub-millimeter resolution at a target range of 10.1 km (in fiber) is observed. A pulse tagging scheme based on phase modulation is demonstrated for range resolved measurements. A carrier to noise ratio of 30 dB is observed at an unambiguous target distance of 30 meters in fiber.

500-Hz Comb Linewidth

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.

Range resolved lidar for long distance ranging with sub-millimeter resolution

A 10.287 GHz optoelectronic oscillator is experimentally demonstrated that uses a 1000 finesse Fabry-Perot etalon as the mode selector instead of an rf filter. The results are compared with a standard optoelectronic loop with an rf filter. The substitution of the rf filter with the optical filter results in a higher rf stability and lower phase noise.

Low Noise Optically Tunable Opto-Electronic Oscillator With Fabry–Perot Etalon

An eXtreme Chirped Pulse Oscillator (XCPO) implemented with a Theta cavity and based on a semiconductor optical amplifier (SOA) is presented for generating 10 ns frequency-swept pulses and 3.6 ps compressed pulses directly from the oscillator. In this experiment, we show the two distinct characteristics of the XCPO which are the scalability of the output energy and the mode-locked spectrum. By using these characteristics, we obtain a pulse energy of 58.4 pJ from the stretched pulse and a mode-locked optical bandwidth of 14.6 nm (10 dB) directly from the oscillator. The laser cavity design allows for low repetition rate operation <100 MHz, as well. The cavity, significantly, reduces nonlinear carrier dynamics, integrated self phase modulation (SPM), and fast gain recovery in an SOA. Due to the lasers ability to generate directly frequency-swept pulses from the oscillator, this oscillator can be used for high speed frequency-swept optical coherence tomography (OCT) and time-stretched photonic analog to digital converters (P-ADC).

Optoelectronic loop design with 1000 finesse Fabry-Perot etalon

Extensive noise analysis is presented of a semiconductor-based coupled opto-electronic oscillator using continuous-wave optical injection for the generation of an optical frequency comb with 10.24 GHz spacing. The suppression of unwanted optical axial mode groups arising from the harmonic nature of mode locking is achieved via gain competition. Amplitude noise measurements show a marked reduction in noise due to optical injection for multiple injection powers. Supermode noise spur suppression is shown to be greater than 15 dB in absolute phase noise measurements, taken using the frequency discriminator technique. Allan deviation measurements are also shown for both the free-running and injection-locked states.

eXtreme Chirped Pulse Oscillator Operating in the Nanosecond Stretched Pulse Regime

Self-phase modulation in fiber amplifiers can significantly degrade the quality of compressed pulses in chirped pulse amplification systems. Parabolic pulses with linear frequency chirp are suitable for suppressing nonlinearities, and to achieve high peak power pulses after compression. In this paper, we present an active time domain technique to generate parabolic pulses for chirped pulse amplification applications. Pulses from a mode-locked laser are temporally stretched and launched into an amplitude modulator, where the drive voltage is designed using the spectral shape of the input pulse and the transfer function of the modulator, resulting in the generation of parabolic pulses. Experimental results of pulse shaping with a pulse train from a mode-locked laser are presented, with a residual error of less than 5%. Moreover, an extinction ratio of 27 dB is achieved, which is ideal for chirped pulse amplification applications.

Noise Characterization of an Injection-Locked COEO With Long-Term Stabilization

A novel method of measuring the optical frequency stability of a continuous-wave (CW) laser by using an etalon-based optoelectronic oscillator is demonstrated. A 1000 finesse Fabry-Pérot etalon is used as a reference which eliminates the need of using an independent optical source as a frequency reference. Using this technique, the optical frequency stability of a CW laser is measured with ~3.5-kHz optical frequency resolution at update rates of 90 Hz.

Dynamic parabolic pulse generation using temporal shaping of wavelength to time mapped pulses

In this work a narrow linewidth (1 kHz) laser source is used to measure the free spectral range of a fiberized Fabry-Perot etalon with sub-Hz accuracy (10(-8)). A previously demonstrated technique based on the Pound-Drever-Hall error signal is improved in accuracy by the use of a narrow linewidth laser swept in frequency via an acousto-optic modulator, or single sideband generation. The sub-Hz (10(-8)) accuracy attained enables the characterization of both the long-term drift and the polarization dependence of the free spectral range of the fiberized etalon.

Optical Frequency Stability Measurement Using an Etalon-Based Optoelectronic Oscillator

A semiconductor-based mode-locked laser source with low repetition rate, ultralow amplitude, and phase noise is introduced. A harmonically mode-locked semiconductor-based ring laser is time demultiplexed at a frequency equal to the cavity fundamental frequency (80MHz), resulting in a low repetition rate pulse train having ultralow amplitude and phase noise, properties usually attributed to multigigahertz repetition rate lasers. The effect of time demultiplexing on the phase noise of harmonically mode-locked lasers is analyzed and experimentally verified.