scholarly journals A tunable wavelength routing scheme based on the sum-and difference-frequency generation with double pass configuration and its applications

2008 ◽  
Vol 57 (2) ◽  
pp. 909
Author(s):  
Yu Song ◽  
Zhang Hua ◽  
Shen Jing ◽  
Zhang Yong-Jun ◽  
Gu Wan-Yi
Keyword(s):  
Difference Frequency Generation ◽  
Difference Frequency ◽  
Wavelength Routing ◽  
Double Pass ◽  
Routing Scheme ◽  
Tunable Wavelength ◽  
Frequency Generation

Flattop Broadband Wavelength Conversion Based on Cascaded Second-Harmonic Generation and Difference Frequency Generation in Step-Segmented Quasi-Phase Matched Gratings

2014 ◽  
Vol 989-994 ◽  
pp. 3790-3793
Author(s):  
Hai Dong Wu ◽  
Jin Song Guo ◽  
Yun Wen Wu ◽  
Zhao Xia Wang
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Wavelength Conversion ◽  
Second Harmonic ◽  
Difference Frequency Generation ◽  
Difference Frequency ◽  
Double Pass ◽  
Single Pass ◽  
Frequency Generation ◽  
Matching Response

Bandwidth enhancement and response flattening of wavelength conversion based on single-pass and double-pass cascaded second harmonic generation and difference frequency generation in step-segmented quasi-phase matched (QPM) gratings are investigated. For the same waveguide length, high conversion efficiency, flat response and broad signal bandwidth can be obtained simultaneously by optimizing the poling period of the step-segmented QPM structure. The conversion bandwidths in a 3-cm-long five-step-segmented waveguide are 134 nm for single-pass scheme and 132 nm for the double-pass one, respectively, which are both over the whole conventional band and long-wavelength band. The ripple on the matching response can keeps less than 0.2 dB as well.

Investigation of Broadband Wavelength Conversion Based on Cascaded Second-Harmonic Generation and Difference Frequency Generation

2015 ◽  
Vol 738-739 ◽  
pp. 759-762
Author(s):  
Jin Song Guo ◽  
Zhao Xia Wang ◽  
Hai Dong Wu ◽  
Yun Wen Wu
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Wavelength Conversion ◽  
Second Harmonic ◽  
Difference Frequency Generation ◽  
Difference Frequency ◽  
Double Pass ◽  
Single Pass ◽  
Chirped Gratings ◽  
Frequency Generation

Step-chirped gratings is utilized to broaden the bandwidth of wavelength conversion based on single-pass/ double-pass cascaded second harmonic generation and difference frequency generation. By adding the step-chirped gratings number and optimizing the poling period, broad conversion bandwidth and flat response can be obtained simultaneously. The bandwidth of 4-cm-long waveguide with 6-section chirped gratings are 169 nm for single-pass scheme and 164 nm for the double-pass one, which are 98 nm and 101 nm larger than those of uniform gratings, respectively. Furthermore, comparison between step-chirped gratings and equal-segmented gratings is carried out.

scholarly journals Spectroscopic Imaging with an Ultra-Broadband (1–4 THz) Compact Terahertz Difference-Frequency Generation Source

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 336
Author(s):  
Atsushi Nakanishi ◽  
Shohei Hayashi ◽  
Hiroshi Satozono ◽  
Kazuue Fujita
Keyword(s):  
Imaging Technique ◽  
Spectroscopic Imaging ◽  
Difference Frequency Generation ◽  
Difference Frequency ◽  
Quality Monitoring ◽  
Terahertz Emission ◽  
Mid Infrared ◽  
Quantum Cascade ◽  
Frequency Generation ◽  
Multi Mode

We demonstrate spectroscopic imaging using a compact ultra-broadband terahertz semiconductor source with a high-power, mid-infrared quantum cascade laser. The electrically pumped monolithic source is based on intra-cavity difference-frequency generation and can be designed to achieve an ultra-broadband multi-mode terahertz emission spectrum extending from 1–4 THz without any external optical setup. Spectroscopic imaging was performed with three frequency bands, 2.0 THz, 2.5 THz and 3.0 THz, and as a result, this imaging technique clearly identified three different tablet components (polyethylene, D-histidine and DL-histidine). This method may be highly suitable for quality monitoring of pharmaceutical materials.

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