Segmental Measurement of High-speed Photodiodes Based on Pre-definable Electro-optic Frequency Comb

• Published in: Journal of lightwave technology 2024-10, p.1-6
• Main Authors: Xu, Ying, Zou, Xinhai, Zhu, Junfeng, Jing, Chao, Li, Heping, Zhang, Zhiyao, Zhang, Yali, Zhang, Shangjian, Liu, Yong, Zhu, Ninghua
• Format: Article
• Language: English
• Subjects: electro-optic frequency comb; Electro-optic modulators; Frequency measurement; Frequency modulation; Frequency response; frequency-shifted heterodyne; Microwave theory and techniques; Optical interferometry; Optical mixing; Optical modulation; Optical polarization; Optical variables measurement; Phase modulation; photodetector
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2024.3487173

A segmental method utilizing a pre-definable electro-optic frequency comb (EOFC) is proposed for characterizing the frequency response of high-speed photodiodes (PDs). The EOFC is generated through frequency shifting and phase modulation of a continuous light wave, with the comb teeth defined by adjusting the electrical power applied to the electro-optic phase modulator (EOPM). By employing the Jacobi-Anger identity, the uneven comb teeth of the EOFC can be equalized. The EOFC signal is combined with a sweeping optical signal produced by an electro-optic modulator (EOM) to create a segmental up-conversion stimulus for probing the PD under test. This approach allows for scalable measurements of PDs across a frequency range exceeding ten times the sweeping frequency of the EOM. A proof-of-concept experiment demonstrates the feasibility of the proposed method, achieving a measurement frequency range of 70 GHz when the frequency is swept up to 7 GHz. The consistency observed between the proposed method and conventional techniques validates the efficacy of frequency response measurements for PDs, showcasing a segmental and scalable capacity based on the pre-definable EOFC.