Microsphere-Based Optical Frequency Comb Generator for 200 GHz Spaced WDM Data Transmission System

Abstract

Optical frequency comb (OFC) generators based on whispering gallery mode (WGM) microresonators have a massive potential to ensure spectral and energy efficiency in wavelength-division multiplexing (WDM) telecommunication systems. The use of silica microspheres for telecommunication applications has hardly been studied but could be promising. We propose, investigate, and optimize numerically a simple design of a silica microsphere-based OFC generator in the C-band with a free spectral range of 200 GHz and simulate its implementation to provide 4-channel 200 GHz spaced WDM data transmission system. We calculate microsphere characteristics such as WGM eigenfrequencies, dispersion, nonlinear Kerr coefficient with allowance for thermo-optical effects, and simulate OFC generation in the regime of a stable dissipative Kerr soliton. We show that by employing generated OFC lines as optical carriers for WDM data transmission, it is possible to ensure error-free data transmission with a bit error rate (BER) of 4.5 × 10−30, providing a total of 40 Gbit/s of transmission speed on four channels.

Kerr-Raman Optical Frequency Combs in Silica Microsphere Pumped Near Zero Dispersion Wavelength

“…Furthermore, there was no Kerr comb near λ p for f R = 0 (Figure 3(f)), so the spectral lines near the pump wavelength in Figures 3(d,e) may be explained by the non-zero Raman gain at small frequencies and/or nondegenerate FWM between pump light and lines belonging to Raman OFC. Note that it was earlier demonstrated theoretically that the Raman response at small frequencies affects the OFC spectral shape at the pump frequency [28,34].…”

“…The spectra of output signals were recorded by OSA (Optical Spectrum Analyzer, Yokogawa AQ6370D). To optimize the ZDW and find the required size of the silica MS, we calculated dispersion β 2 for different radii R using the approach based on numerical solution of a characteristic equation [26] as in our previous works [27,28]. We found eigenfrequencies ν l for the fundamental transverse electric mode families, where l is the azimuthal mode index, and after that we calculated β 2 as follows [29,30]:…”

“…The nonlinear Kerr coefficients found for different radii are plotted in Figure 2(b). The nonlinear dynamics of an intracavity field leading to OFC generation was simulated numerically in the framework of the LLE [6,32] as in [28,33] using home-made software based on the Split-step Fourier method. We used the master equation in the following form [6,29,34]:…”

IM/DD WDM-PON Communication System Based on Optical Frequency Comb Generated in Silica Whispering Gallery Mode Resonator

“…We calculated the dispersion of the produced silica WGMR using the method described in detail in our previous work [36], [37]. We solved numerically the characteristic equation obtained from Maxwell's equations to find eigenfrequencies of the WGMR and after that to calculate the dispersion β 2 for the fundamental modes.…”

Optical Frequency Combs Generated in Silica Microspheres in the Telecommunication C-, U-, and E-Bands

“…Silica microresonators made of a standard optical fiber are suitable for application in the telecommunication range, since they can be pumped by narrow-linewidth C-band telecom lasers, and the corresponding experimental schemes are based on standard telecom components. Recently, we studied theoretically [23,24] and demonstrated experimentally [25] the implementation of wavelength division multiplexed-passive optical network (WDM-PON) in the C-band using an OFC generator based on a silica microsphere as a multiple light source. When several lasers (laser array) are replaced by a single OFC source, it improves the energy efficiency of the WDM fiber optical communication system, at the same time providing stable frequency spacing and strong phase relation between generated carriers (modes) [24][25][26].…”