Photonic generation of linearly chirped microwave waveforms using a monolithic integrated three-section laser

Abstract

Photonic generation of linearly chirped microwave waveforms (LCMWs) using a monolithic integrated three-section laser is experimentally demonstrated in this work. All three sections of the laser cavity, including the front DFB section, phase section and rear DFB section, have the same active layer, which can avoid the butt-joint re-growth process. The gratings in both DFB sections are fabricated by the Reconstruction Equivalent Chirp technique, which can significantly decrease the difficulties in realizing precise grating structure. By adjusting the integrated three-section semiconductor laser to work in the period-one (P1) state and applying a sweeping signal to the front DFB section, the beating signal, i.e., an LCMW with a large time bandwidth product (TBWP), can be generated. In the current proof-of-concept experiment, an LCMW with a large TBWP up to 5.159 × 10 is generated, of which the bandwidth and the duration time are 6.7 GHz and 77 us respectively. The compressed pulse width is 150 ps. In addition, by adjusting the bias currents of the rear DFB section and front DFB section as well as the amplitude of the sweeping signals, LCMWs with tunable center frequency and tunable bandwidth can be achieved.

High performance chirped microwave generator for space applications

“…The lightwave from the power splitter is phase modulated by the PM [16]. The optical beam at the PM output passes through the sensitive element (PhCRR), that acts as optical filter and time delay element [24,25], is amplified by the SOA2 [11], and, then, O/E transduced by a photodiode. The photodiode output is filtered, phase shifted and then fed back to the modulator.…”

“…The easy implementation makes this technique interesting, but the method presents TBWP in the order of tens at central frequency > 20 GHz. Period-one dynamics of an optically injected modulated laser [10] or dual-mode state of a single monolithically integrated amplified feedback laser [11] are used to develop injected laser-based chirp generator technique. Many discrete photonic components are required for the former approach, making the configuration bulky.…”

Chip-Scaled Ka-Band Photonic Linearly Chirped Microwave Waveform Generator

“…Photonic approaches for LCMW generation proposed in the literature are mainly based on temporal pulse shaping, wavelength/frequency/space-to-time mapping technique, optically injected lasers, interferometers, and optoelectronic oscillators [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. The temporal pulse shaping technique is based on the amplitude modulation of an ultrashort optical signal and the processing by using conjugated or mismatched chromatic dispersion elements.…”

Chirped Microwave Signals Generation Using a Distributed Feedback Laser With Alternating Structure of Active- and Passive-Cavity

“…Chirped microwave signals find important applications in modern radar systems [1], wireless communication [2], medical imaging systems [3], and optoelectronic devices [4]. Conventionally, the pure electric methods including phase-locked loop (PLL) [5] and direct digital frequency synthesizer (DDS) [6] are generally adopted to generate microwave signals.…”