Comparative analysis of spectral coherence in microresonator frequency combs

Abstract

Abstract:Microresonator combs exploit parametric oscillation and nonlinear mixing in an ultrahigh-Q cavity. This new comb generator offers unique potential for chip integration and access to high repetition rates. However, time-domain studies reveal an intricate spectral coherence behavior in this type of platform. In particular, coherent, partially coherent or incoherent combs have been observed using the same microresonator under different pumping conditions. In this work, we provide a numerical analysis of the coherence dynamics that supports the above experimental findings and verify particular design rules to achieve spectrally coherent microresonator combs. A particular emphasis is placed in understanding the differences between so-called Type I and Type II combs. and T. W. Hänsch, "Direct link between microwave and optical frequencies with a 300 THz femtosecond laser comb," Phys. Rev. Lett. 84, 5102-5105 (2000). 3. T. W. Hänsch, "Nobel Lecture: Passion for precision," Rev. Mod. Phys. 78, 1297-1309(2006. 4. N. R. Newbury, "Searching for applications with a fine-tooth comb," Nature Photon. 5, 186-188 (2011). 5. V. Torres-Company and A. M. Weiner, "Optical frequency comb technology for ultra-broadband radio-frequency photonics," Laser and Photon. Rev. (in press, 2013). DOI 10.1002/lpor201300126. 6. T. J. Kippenberg, R. Holzwarth, and S. A. Diddams, "Microresonator-based optical frequency combs," Science 332, 555-559 (2011). 145-152 (2014). 43. F. Leo, S. Coen, P. Kockaert, S. P. Goza, P. Emplit, and M. Haelterman, "Temporal cavity solitons in onedimensional Kerr media as bits in an all-optical buffer," Nat. Photonics 4, 471-476 (2010). 44. H. Lajunen, V. Torres-Company, J. Lancis, E. Silvestre, and P. Andres, "Pulse-by-pulse method to characterize partially coherent pulse propagation in instantaneous nonlinear media," Opt. Express 18, 14979-14991 (2010). 45. M. Erkintalo and S. Coen, "Coherence properties of Kerr frequency combs," Opt. Lett. 39, 283-286 (2014). 46. M. Haelterman, S. Trillo, and S. Wabnitz, "Additive-modulation-instability ring laser in the normal dispersion regime of a fiber," Opt. Lett. 17, 745-747 (1992). 47. I. V. Barashenkov and Y. S. Smirnov, "Existence and stability chart for the ac-driven, damped nonlinear Schrodinger solitons," Phys. Rev. E 54, 5707-5725 (1996)

Triply resonant coherent four-wave mixing in silicon nitride microresonators

“…4. What is interesting to note from this analysis, is that the maximum conversion efficiency will take place for a phase matching condition similar to the case of modulation instability in microresonator frequency combs pumped by a single CW laser [23].…”

Harmonic mode locking in a high-Qwhispering gallery mode microcavity

“…Furthermore, there is a limitation as regards achieving a high repetition rate, because active mode locking requires a fast electro-optic modulator. In contrast, the study of passive harmonic mode locking in a microcavity has just begun [16,17]. Even though the underlying physics of harmonic mode locking is the same for both a microcavity and a fiber oscillator, the FSR mode spacing R is large and it can satisfy R > FWM in a microcavity, where FWM is the gain bandwidth of the four wave mixing.…”

Bandwidth shaping of microresonator-based frequency combs via dispersion engineering

“…In this Letter, we theoretically and experimentally investigate the role of group-velocity dispersion (GVD) and higher-order dispersion on the bandwidth of siliconnitride-based parametric frequency combs. We show that dispersion engineering in the silicon-nitride (Si 3 N 4 ) platform allows for control of the comb bandwidth and power in the comb to adapt to a particular application.We use a theoretical model based on a modified Lugiato-Lefever equation (LLE) to fully simulate the dynamics of comb generation in Si 3 N 4 microring resonators [11][12][13][14][15][16][17][18][19]. The modified LLE describes the propagation of the intracavity field Et; τ in the microring and is written as,…”

“…Our modified LLE model, which includes higher-order dispersion and self-steepening, enables simulations of combs spanning an octave of bandwidth [16] and has shown excellent agreement with previous experimental demonstration. We investigate the effects of these terms on sideband generation from FWM by analyzing the coupled mode equations associated with the field Et; τ A 0 A A − [19][20][21], where A 0 is the pump field and A and A − represent the symmetrically detuned sidemodes. For our analysis, we assume that the amplitude of the sidebands are much smaller than A 0 , in which case the coupled equations are given as…”

“…We use a theoretical model based on a modified Lugiato-Lefever equation (LLE) to fully simulate the dynamics of comb generation in Si 3 N 4 microring resonators [11][12][13][14][15][16][17][18][19]. The modified LLE describes the propagation of the intracavity field Et; τ in the microring and is written as,…”