Silicon does not emit light efficiently, therefore the integration of other light-emitting materials is highly demanded for silicon photonic integrated circuits. A number of integration approaches have been extensively explored in the past decade. Here, the most recent progress in this field is reviewed, covering the integration approaches of III-V-to-silicon bonding, transfer printing, epitaxial growth and the use of colloidal quantum dots. The basic approaches to create waveguide-coupled on-chip light sources for different application scenarios are discussed, both for silicon and silicon nitride based waveguides. A selection of recent representative device demonstrations is presented, including high speed DFB lasers, ultra-dense comb lasers, short (850nm) and long (2.3μm) wavelength lasers, wide-band LEDs, monolithic O-band lasers and micro-disk lasers operating in the visible. The challenges and opportunities of these approaches are discussed.

Abstract:In the paper, we review our work on heterogeneous III-V-on-silicon photonic components and circuits for applications in optical communication and sensing. We elaborate on the integration strategy and describe a broad range of devices realized on this platform covering a wavelength range from 850 nm to 3.85 μm.

Abstract-Single-mode 1.5-µm InP-based vertical-cavity surface-emitting lasers (VCSELs) with a 1.5-λ long semiconductor cavity and two dielectric distributed Bragg reflectors (DBRs) are presented. The electrical, thermal and optical characteristics are studied as a function of tunnel junction diameter and for different temperatures ranging from -10°C up to 65°C. Small-signal modulation bandwidths in excess of 21 GHz at room temperature are demonstrated for a DC power consumption below 10 mW. In this paper, the superior dynamic characteristics of these VCSELs are shown by demonstrating error-free operation at data rates up to 50 Gb/s in back-to-back configuration by non-return-to-zero modulation and without any equalization. Neither forward error correction nor digital signal processing were required.

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Optical homodyne detection is used in numerous quantum and classical applications that demand high levels of sensitivity. However, performance is typically limited due to the use of bulk optics and discrete receiver electronics. To address these performance issues, in this work we present a co-integrated balanced homodyne detector consisting of a silicon photonics optical front end and a custom integrated transimpedance amplifier designed in a 100 nm GaAs pHEMT technology. The high level of co-design and integration provides enhanced levels of stability, bandwidth, and noise performance. The presented detector shows a linear operation up to 28 dB quantum shot noise clearance and a high degree of common-mode rejection, at the same time achieving a shot-noise-limited bandwidth of more than 20 GHz. The high performance of the developed devices provide enhanced operation to many sensitive quantum applications such as continuous variable quantum key distribution, quantum random number generation, or high-speed quantum tomography.

Abstract:We demonstrate low-voltage germanium waveguide avalanche photodetectors (APDs) with a gain×bandwidth product above 100GHz. A photonic receiver based on such a Ge APD, including a 0.13µm SiGe BiCMOS low-noise trans-impedance amplifier and a limiting amplifier, is realized. A 5.8dB sensitivity improvement is demonstrated at -5.9V bias at an avalanche gain of 6 through bit error ratio measurements. The absolute sensitivity in avalanche mode is -23.4dBm and -24.4dBm at a bit error ratio of 1×10-12 and 1×10 -9 respectively. ©2014 Optical Society of America

Abstract-With the continuously increasing demand of cost effective, broadband wireless access, radio-over-fiber (RoF) starts to gain more and more momentum. Various techniques already exist, using analog (ARoF) or digitized (DRoF) radio signals over fiber. Each with their own advantages and disadvantages. By transmitting a sigma delta modulated signal over fiber (SDoF), a similar immunity to impairments as DRoF can be obtained while maintaining the low complexity of ARoF. This letter describes a detailed experimental comparison between ARoF and SDoF that quantifies the improvement in linearity and error vector magnitude (EVM) of SDoF over ARoF. The experiments were carried out using a 16QAM constellation with a baudrate from 20 to 125 Mbaud modulated on a central carrier frequency of 1 GHz. The sigma delta modulator (SDM) runs at 8 or 13.5 Gbps. A high speed VCSEL operating at 850 nm is used to transmit the signal over 200 m multimode fiber. The receiver amplifies the electrical signals and subsequently filters to recover the original RF-signal. Compared to ARoF, improvements exceeding 40 dB were measured on the third order intermodulation products when SDoF was employed, the EVM improves between 2.4 to 7.1 dB.