Enhanced Optical Frequency Comb Generation through Multitone Reciprocating Optical Modulation

The advent of optical frequency combs (OFCs) has revolutionized photonics, enabling transformative advancements in fields such as millimeter-wave generation, spectroscopy, and precision metrology. This work proposes and investigates, through simulations, a simple yet efficient method for OFC generation with enhanced power per comb line, particularly at higher-order sidebands. The proposed system utilizes a phase modulator, placed between an input narrow passband filter and an output stopband filter, driven by harmonically related RF signals. In the case of two driving signals, this configuration achieves up to a 50 dB enhancement in the power of the 20th-order sideband, compared to conventional multitone phase modulation using the same driving signals. This technique overcomes tunability constraints of mode-locked lasers, avoids the complexities of Kerr-comb and SBS-based methods, and simplifies system architecture by reducing component count. The proposed system is highly compatible with photonic integrated circuits, offering compactness, scalability, and integration potential for advanced OFC applications.