RESUMEN
We propose a rapid and precise scheme for characterizing the full-field frequency response of a thin-film lithium niobate-based intensity modulator (TFLN-IM) via a specially designed multi-tone microwave signal. Our proposed scheme remains insensitive to the bias-drift of IM. Experimental verification is implemented with a self-packaged TFLN-IM with a 3â dB bandwidth of 30â GHz. In comparison with the vector network analyzer (VNA) characterization results, the deviation values of the amplitude-frequency response (AFR) and phase-frequency response (PFR) within the 50â GHz bandwidth are below 0.3â dB and 0.15â rad, respectively. When the bias is drifted within 90% of the Vπ range, the deviation fluctuation values of AFR and PFR are less than 0.3â dB and 0.05â rad, respectively. With the help of the full-field response results, we can pre-compensate the TFLN-IM for the 64â Gbaud PAM-4 signals under the back-to-back (B2B) transmission, achieving a received optical power (ROP) gain of 2.3â dB. The versatility of our proposed full-field response characterization scheme can extend to various optical transceivers, offering the advantage of low cost, robust operation, and flexible implementation.
RESUMEN
We demonstrate a circulator-free thin-film lithium niobate (TFLN) dispersion compensator based on the cascading 2 × 2 multimode interferometer (MMI) and two identical chirped Bragg gratings (CBGs). The cascaded MMI-CBG structure provides a dispersion value of 920â ps/nm/m over a 20â nm bandwidth covering 1537 to 1557â nm, featuring a compact footprint of 1â mm × 0.7â mm. Utilizing this device within a TFLN electro-optic time-lens system, we successfully generate 863-fs pulses at a 37â GHz repetition rate. Our compact, scalable, low-loss, and circulator-free dispersion compensator is the building block for the efficient generation of high-peak-power femtosecond laser pulses.