Photonic Generation of Triangular Waveform Utilizing Time-Domain Synthesis

Abstract

We propose and demonstrate a new photonic approach for triangular waveform generation. Based on an optical signal with sinusoidal envelope, an injection-locking process in a distributed-feedback semiconductor laser diode is employed to carry out the desired harmonic signal generation, and then the tailored signal is synthesized by the superimposition of these signals with proper power ratio and time delay. In this method, the conventional spectral line manipulating is transferred to individual signal envelope control, which reduces the technical requirement while the flexibility and accuracy is improved. In the experiment demonstration, triangular waveforms with the repetition frequencies of 9, 10, and 12 GHz are successfully generated. The results well agree with the theoretical predication and show great potential to realize arbitrary waveform generation.

Flexible Microwave Waveforms Synthesis Based on Wavelength Sensitive Bias Shift of a Mach–Zehnder Modulator

“…Time-domain synthesis is another effective way to generate desired waveforms. In this method, the wanted signals can be achieved by carving and overlapping the signal envelopes in time domain [12], [15]- [17], where the modulator implements the envelope graver. This technique avoids the optical spectral line manipulation, but the operation bandwidth is greatly limited by the bandwidth of modulator.…”

A Photonic-Assisted Generation of Triangular Waveform With Frequency Octupling

“…In these schemes, no additional radio frequency (RF) source is required. In addition, triangular waveform generation based on time-domain synthesis (TDS) has also been proposed recently [12][13][14][15][16]. In Ref.…”

“…In Ref. [12,13], Y. Jiang et al proposed photonic approaches to generate microwave waveforms by synthesizing and carving optical field envelopes in time-domain. In Ref.…”

Photonic Generation of Triangular-shaped Waveform Based on External Modulation

“…The drawback of this kind of schemes is that the use of mode-locked laser (MLL) leads to a high cost and the generated triangular waveforms have small duty cycle (<1), which cannot satisfy the requirement in many applications where a full duty cycle (=1) is desired. To resolve this issue, generations based on external modulation of a continuous wave (CW) light using electro-optical modulators are proposed 8 – 16 . The basic principle of this kind of approach is to control the harmonics of optical intensity approximately equal to the first two-term Fourier components of a triangular waveform.…”

“…The structure based on interleaver suffers from stability problem, and structure based on dispersive fiber suffers low tenability of repetition rate of the generated waveform. In addition to the approaches mentioned above, triangular waveform has also been obtained by using frequency comb generation and optical spectrum manipulation 14 , and time-domain synthesis 15 , 16 . Through these approaches, it can be seen that external modulation could effectively reduce the complexity of operation.…”