[17a-Z08-1~11] 3.8 Optical measurement, instrumentation, and sensor

[17a-Z08-6] Enhancement of Bandwidth and Dynamic Range in Differential Noise Cancellation for White Pulsed Light based on Time Division Detection of Probe and Reference Pulses

〇Keisuke Seto¹, Takayoshi Kobayashi², Eiji Tokunaga¹ (1.Tokyo Univ. Sci., 2.Univ. Electro-Commun.)

Keywords:noise-cancellation, photonic crystal fiber, stimulated Raman

In pump/probe measurements such as stimulated Raman spectroscopy, the noise of probe light (Pr) mostly determines the signal to noise ratio. We have developed a noise cancellation technique for white probe pulse light in spectroscopic pump/probe measurements. In the noise cancellation, Pr and reference pulse light (Rf) are time-division-multiplexed through an additional optical path for Rf and demultiplexed after detecting the multiplexed pulses through a common spectrometer. The noise in demultiplexed Rf is subtracted from that in Pr. However, although the shot-noise limited performance was achieved at the low-frequency region, the performance was degraded at high observation-frequencies. Further, the performance was also found to deteriorate at high optical power. In this talk, we will present a guide to improve the bandwidth and dynamic range of the noise cancellation technique.