(b) Optical spectra for different parameters simulated in panel (a) (1, 2, 3) show a narrow spectral width for high values of D 2 and asymmetric spectra, as well as dispersive wave phenomena (peak at μ = − 65) for nonzero D 3. (a) The ratio P peak / P avg of peak to average intracavity power is used as an indicator of soliton formation (which results in high peak power) for different combinations of D 2 and D 3. Numerical investigation of soliton formation in different dispersion scenarios. A simple parametrization using magnitude a and position b of the avoided mode crossing can be used for numerical modeling. (d) Illustration of mode coupling induced mode frequency shift altering the dispersion properties locally. The gray line indicates anomalous GVD described by D 2 only. (c) Illustration of higher order dispersion with D 3 > 0. The mode family shows signs of mode coupling to other mode families. (b) Comparable measurement of the fundamental TM11 mode in a Si 3 N 4 microresonator with a resonator linewidth of 350 MHz and approximate FSR of 76 GHz (consisting of a 800 nm high and 2 μ m wide Si 3 N 4 waveguide embedded in SiO 2). The color codes the measured resonance depth and helps to track particular mode families. Four specific mode families have been numbered by yellow labels. The dispersion can be strongly affected by mode crossings.
#OPTICAL SPECTRUM QUANTUMWISE FREE#
Different free spectral ranges correspond to different slopes of the lines, whereas dispersion and variation of the free spectral range show as a curvature of the lines (convex and concave curvatures correspond to anomalous and normal GVD, respectively). Dots forming a continuous line represent a particular mode family. (a) Mode structure of a MgF 2 resonator with linewidths in the range of 50–500 kHz and an approximate FSR of 14.09 GHz, as measured by frequency comb assisted diode laser spectroscopy.
![optical spectrum quantumwise optical spectrum quantumwise](https://www.synopsys.com/content/dam/synopsys/silicon/quantum-atk/resources-publications.jpg)
Conventional fiber is used for dispersion compensation. After attenuation of the pump laser, the remaining soliton spectrum has been amplified to approximately 30 mW of the average optical power. The second harmonic frequency ω SHG / 2 π is centered around 384 THz. The pulses are separated by 71 ps corresponding to the inverse repetition rate (The FROG measurement uses second harmonic generation in a beta barium borate crystal. (b) Frequency resolved optical gating (FROG) of the ultrashort pulses outcoupled from the resonator. The inset shows the resolution bandwidth (RBW) limited rf signal at a frequency of 14.09 GHz corresponding to the soliton pulse repetition rate. The pump power is 30 mW at a wavelength of 1552 nm. The spectral 3-dB width of 13 nm (1.62 THz) corresponds to a soliton pulse duration of 194 fs (full width at half maximum). (a) Measured optical spectrum with smooth sech 2-shaped spectral envelope (red line) of a single temporal soliton generated in a continuous wave laser driven crystalline high-finesse MgF 2 microresonator. The presented results provide for the first time design criteria for the generation of temporal solitons in optical microresonators. The experimental observations are in excellent agreement with numerical simulations based on the nonlinear coupled mode equations. Avoided mode crossings induced by linear mode coupling in the resonator mode spectrum are found to prevent soliton formation when affecting resonator modes close to the pump laser frequency. While an overall anomalous group velocity dispersion is required, it is found that higher order dispersion can be tolerated as long as it does not dominate the resonator’s mode structure. Here we study the influence of the microresonator mode spectrum on temporal soliton formation in a crystalline MgF 2 microresonator.
![optical spectrum quantumwise optical spectrum quantumwise](https://docs.quantumatk.com/_images/transmission_spectrum_-1.4eV.png)
The formation of temporal dissipative solitons in optical microresonators enables compact, high-repetition rate sources of ultrashort pulses as well as low noise, broadband optical frequency combs with smooth spectral envelopes.