Repetition-rate-tunable return-to-zero and carrier-suppressed return-to-zero optical pulse train generation using a...

Area of Science:

• Photonics
• Optical Communications
• Signal Processing

Background:

• High-repetition-rate optical pulse generation is crucial for modern communication systems.
• Existing methods for generating return-to-zero (RZ) and carrier-suppressed RZ (CS-RZ) pulse trains often face limitations in repetition rate and tunability.
• Polarization modulators (PolMs) offer unique properties for manipulating light polarization and phase.

Purpose of the Study:

• To propose and demonstrate a novel approach for generating RZ and CS-RZ pulse trains.
• To achieve high and tunable repetition rates for these pulse trains.
• To utilize a polarization modulator (PolM) as the core component for pulse generation.

Main Methods:

• A polarization modulator (PolM) was employed, capable of supporting TE and TM modes with opposite phase modulation indices.
• Linearly polarized continuous-wave (cw) light was modulated by a sinusoidal signal at a 45-degree angle to the PolM's principal axis.
• The modulated light was directed to a polarization beam splitter (PBS), separating even and odd optical sidebands to form RZ and CS-RZ pulses.

Main Results:

• The proposed method successfully generated RZ and CS-RZ pulse trains.
• The repetition rate of the generated pulses was twice the frequency of the drive sinusoidal signal.
• A proof-of-concept experiment demonstrated tunable repetition rates of 7.2 GHz and 8 GHz.

Conclusions:

• The polarization modulator-based approach offers an effective method for generating high-repetition-rate RZ and CS-RZ pulse trains.
• The technique provides tunability in repetition rates, making it suitable for flexible optical communication applications.
• This method presents a promising solution for advancing optical signal generation.