High Repetition Rate Optical Pulse Research Articles

Phase Noise of Optical Pulse Trains Generated by Talbot Effect in Frequency Shifting Loops

High repetition rate optical pulse trains are essential for a wide range of applications, including photonic-assisted sampling. Among the different solutions proposed so far, Talbot lasers, based on the generation of an optical frequency comb in a frequency shifting loop, are a simple yet efficient source of short transform-limited pulses. By controlling the comb spectral phase, the repetition rate is reconfigurable. It can be set to a (possibly large) multiple of the comb spacing and reach the GHz range, while only requiring a low bandwidth synthesizer (typ. 100 MHz). The noise characteristics of this pulse trains is a key factor for its application. Therefore, we investigate the phase noise properties of Talbot lasers. In particular, we prove theoretically and demonstrate experimentally that the phase noise at high offset frequency from the carrier, does not depend on the multiplication factor $q$ . We also demonstrate that the phase noise at low offset frequencies, which increases as $20 \log q$ , can be strongly reduced by a simple locking technique. Finally, we show that in addition to their reconfigurability, Talbot lasers can provide timing jitters at 8.2 GHz as low as 350 fs (integrated from $10^{5}$ Hz to the Nyquist frequency), making them suitable candidates for time metrology applications.

Compact low-noise passively mode-locked Er-doped femtosecond all-fiber laser with 2.68 GHz fundamental repetition rate.

A passively mode-locked Er-doped fiber laser with a fundamental repetition rate of 2.68GHz is reported. The oscillator operating at a central wavelength of 1558.35nm has a compact, robust structure and low-noise performance. The timing jitter integrated from 30MHz down to 300Hz is 82.5fs, and the timing jitter performance is analyzed based on the theory model. The amplification and compression of the high repetition rate optical pulses are also investigated. After a three-stage amplifier, the average power is boosted to 430mW. Meanwhile, based on the nonlinear self-phase modulation effect, the spectral bandwidth is broadened from 7.56 to 19.2nm, and the corresponding pulse width is compressed to 244fs.

Integrated Photonic Chip Enabled Simultaneous Multichannel Wideband Radio Frequency Spectrum Analyzer

Radio frequency (RF) spectrum analysis is an essential technique for monitoring signal quality in ultrahigh-speed optical transmission, broad bandwidth photonic RF arbitrary waveform generation, and for characterization of high repetition rate optical pulse sources. Whereas the intrinsic bandwidth of electronics limits its use for RF spectrum measurement of high-speed signals, a photonic approach based on ultrafast Kerr nonlinear effects can readily measure the RF spectrum of optical signals having a bandwidth beyond 1 THz. The majority of fiber-based or integrated photonic RF spectrum analyzers reported to date can monitor only one channel at a time. We demonstrate how to harness mode-selective excitation of nonlinear optical effects to perform simultaneous multichannel RF spectrum analysis using a single integrated silicon photonic device. This approach, which can be scaled to a higher number of channels, opens up a new degree of freedom for realizing multichannel signal characterization using a single integrated photonic device.

基于法布里-珀罗半导体激光器实现高重复频率光脉冲的时钟分频

基于法布里-珀罗半导体激光器实现高重复频率光脉冲的时钟分频

A method of tunable high repetition-rate picosecond optical pulse generation using injection locking of laser diodes

A method of tunable, high repetition-rate optical pulse generation by using optical injection locking of semiconductor lasers has been described in this paper. This method utilizes the superposition of five coherent optical carriers obtained from the spectrum of optical phase modulation, which results in a sharp optical pulse. Theoretical calculations indicate that a pulse width of 1 ps and a repetition rate of 200 GHz can be achieved for a modulator drive frequency of 40 GHz.

High Repetition Rate Optical Pulse Multiplication with Cascaded Long-period Fiber Gratings

We propose and demonstrate a novel optical pulse multiplier applicable to OTDM (Optical Time Division Multiplexing) systems using cascaded long-period fiber gratings. We have exploited the fact that each mode in a fiber has a different propagation constant to obtain time delays among optical pulses. The proposed scheme could realize high-frequency optical pulse multiplication for optical short pulse trains. We have successfully implemented two, four, and eight times multiplications with the maximum repetition rate of 416.7 ㎓. The obtained pulse delays are well matched with the simulated ones.

High repetition rate optical pulse generation from an actively mode-locked fiber rin laser

Rational harmonic mode-locking of an Er-doped fiber ring laser has been successfully demonstrated up to the 16-th harmonic, of the RF frequency applied to the electro-optic modulator. This is the highest harmonic reported so far to our knowledge.

High-repetition-rate optical pulse generation by using chirped optical pulses

A very high repetition rate optical pulse train is generated by using a chirped optical pulse train obtained with a dispersive medium and an optical pulse laser source. Adjusting the group-velocity dispersion (GVD) of the dispersive medium, we can obtain an optical pulse train at a repetition rate which is a multiple of that of the optical pulse laser source initially used. We have successfully generated a 50 to 400 GHz optical pulse train synchronised with an external clock by using a 10 GHz pulse source and optical fibre as the dispersive medium. We have also numerically confirmed this result.

Subharmonic synchronous and hybrid mode-locking of a monolithic DBR laser operating at millimeter-wave frequencies

A detailed comparison of subharmonic synchronous and subharmonic hybrid mode-locking of a monolithic distributed Bragg reflector (DBR) laser operating at 33 GHz is presented. Optical injection at the 20th subharmonic frequency (1.65 GHz) has produced a locking range of 10 MHz with negligible amplitude modulation. In comparison, electrical injection at the 4th subharmonic frequency (5.83 GHz) has shown higher levels of amplitude modulation and a narrower locking range (4 MHz). While subharmonic hybrid mode-locking remains a simple and cost effective solution for the generation of low timing jitter high-repetition rate optical pulse trains, subharmonic synchronous mode-locking shows superior performance with regard to reduced amplitude modulation and larger locking range.

High repetition rate optical pulse generation by frequency multiplication in actively modelocked fibre ring lasers

The authors report on the generation of optical pulses at repetition rate integer multiples of the RF drive frequency from a harmonically driven actively modelocked fibre ring laser. Optical pulses at repetition rates 21 GHz and 14 GHz are generated solely by controlling the RF drive frequency to the modulator.

Mode-locked laser pulse train repetition frequency multiplication: the optical rattler

We present a simple method for multiplying the pulse repetition frequency of a given cw mode-locked laser. We report, in particular, the doubling and tripling of the c/2L frequency of a synchronously pumped mode-locked dye laser. This technique should prove useful for a variety of ultrashort pulse applications including high repetition rate optical pulse amplification studies, electronic and optical material characterization, optical chaos experiments, and impulsively driven spectroscopy.

Generation of 5 THz repetition optical pulses by modulation instability in optical fibers

5 THz repetition rate optical pulses have been achieved with modulation instability in an optical fiber. The detailed investigation on the relationship between fiber anomalous dispersion and modulation frequency enables high repetition rate optical pulses, yielding a control method of pulse repetition rate.