Wavelength conversion of QAM signals in a low loss CMOS compatible spiral waveguide

Abstract

We demonstrate wavelength conversion of quadrature amplitude modulation (QAM) signals, including 32-GBd quadrature phase-shift keying and 10-GBd 16-QAM, in a 50-cm long high index doped glass spiral waveguide. The quality of the generated idlers for up to 20 nm of wavelength shift is sufficient to achieve a BER performance below the hard decision forward error correction threshold BER performance (<3.8 × 103), with an optical signal-to-noise ratio penalty of less than 0.3 dB compared to the original signal. Our results confirm that this is a promising platform for nonlinear optical signal processing, as a result of both very low linear propagation loss (<0.07 dB/cm) and a large material bandgap, which in turn ensures negligible nonlinear loss at telecom wavelengths.

Optical Phase Conjugation in a Silicon Waveguide With Lateral p-i-n Diode for Nonlinearity Compensation

“…The successful compensation of nonlinear distortion was indeed shown, but the poor conversion efficiency (CE) and thus limited achievable optical signal-to-noise ratio (OSNR) of the conjugate signal prevented a Q-factor improvement at optimum launched power, when compared with straight transmission. Whereas reducing TPA in silicon would require changingthe material properties, for example by looking at amorphous structures [22]- [24] or focusing on silicon-based compound materials [24]- [27], the impact of FCA can be significantly reduced simply by adding n-and p-doped regions across the waveguide. When a reverse bias voltage is applied to these doped regions, the generated electric field sweeps out the accumulated free carriers reducing the nonlinear loss due to FCA [28]- [30].…”

Characterization and Optimization of a High-Efficiency AlGaAs-On-Insulator-Based Wavelength Converter for 64- and 256-QAM Signals

“…However, silicon-based compounds may be more attractive as they could enable benefiting from the well established CMOS fabrication technology. In this regard, several material platforms have been investigated, spanning from crystalline [9] and amorphous silicon [15], to silicon-germanium [15], [16] and siliconnitride [17], as well as high index doped glass [18].…”

“…The bandgap shift comes at the expense of lower Kerr nonlinearity which leads to a low conversion efficiency (CE) and thus only a modest output idler OSNR [18]. A material platform offering high nonlinearity, low propagation loss and a bandgap ensuring TPA-free operation at telecom wavelength is highly desired.…”

Photonic RF channelizer based on 49GHz soliton crystal microcombs

“…Recently, microcombs [27][28][29][30][31], particularly those based on CMOS-compatible platforms [32][33][34][35][36][37][38][39][40], came into focus since they offer a large number of coherent wavelength channels in a mm 2 -size footprint, and have enabled a wide range of RF applications [41,42], such as RF true time delays [43,44], transversal signal processors [45][46][47][48][49][50], frequency conversion [51], phase-encoded signal generators [52], and RF channelizers [53,54]. Previously [54], we reported an RF channelizer based on a microcomb that achieved high performance in a compact footprint.…”