Generation of a Frequency-Quadrupled Phase-Coded Signal With Large Tunability

Abstract

Abstract-A photonic approach for frequency-quadrupled phase-coded signal generation with large tunability is proposed and demonstrated. In the proposed scheme, a dual-parallel Mach-Zehnder modulator is used to generate two second-order optical sidebands, which are made orthogonally polarized in a Sagnac loop incorporating a fiber Bragg grating. Then, a polarization modulator is employed to perform phase coding with high coding rate. A distinct advantage of this approach is the capability to generate a phase-coded signal with a large frequency tuning range, from several MHz to more than 100 GHz. A proof-of-concept experiment is carried out. The generation of a 2.5-Gbit/s phase-coded signal with a frequency tuning from 13 to 30 GHz is experimentally verified.

Photonic generation of tunable phase microwave signal using a feed-back controlled birefringent polarization rotator

“…The latter type has a highly stable carrier frequency because the stability is determined by that of the RF signal generator used for modulation irrespective of the optical frequency stability. Double-sideband suppressed-carrier (DSB-SC) modulation is a good candidate for making such modulation sidebands [18,19,20,21]. However, the two sidebands have to be separated into different optical paths for remote phase control [22,23].…”

Frequency-Octupling Millimeter-Wave Optical Vector Signal Generation via an I/Q Modulator-Based Sagnac Loop

“…In this work, an I/Q modulator-based Sagnac loop used to generate frequency-octupling 16QAM signals is proposed. Usually, the frequency-octupling signal can be generated by a DP-MZM, however the signal suffers from a low optical sideband suppression ratio (OSSR) because of the finite extinction ratio of the DP-MZM [17]. A DP-QPSK modulator is an integrated modulator that can flexibly generate different forms of optical signals and has been widely used in recent reports [18,19].…”

Generation of a frequency-quadrupled phase-coded signal using optical carrier phase shifting and balanced detection

“…The main drawback of this method is that the two optical paths are physically separated and independently processed, which makes the signal suffer severely from environment variations. To improve stability, polarization modulation technique can be utilized, thanks to the complementarily phase-modulation function of the integrated polarization modulator (PolM) [8][9][10][11][12][13]. However, the schemes based on the polarization modulation are usually complicated and costly due to the use of multiple modulators.…”

“…The generation of a frequency-quadrupled phase-coded signal has also been proposed [8], but the polarization maintaining fiber Bragg grating (FBG) used in the scheme is wavelength and polarization dependent, making the frequency tuning range very limited. Recently, we demonstrated a frequency-quadrupled phase-coded signal generator with large tunability based on an FBG-incorporated Sagnac loop and a PolM [13]. Again, the system is complicated because the polarization modulation technique is employed.…”