We report on our recent advances on integrated hybrid InP/SOI transmitters using the Silicon Photonic fabrication technology. We demonstrate the direct modulation at 10 Gbits/s of different laser configurations such as wavelength tunable lasers, Distributed FeedBack (DFB) lasers and Chirp Managed Lasers (CMLs). We will also present the design, fabrication and characterization of various hybrid InP/SOI transmitters integrating lasers (tunable or DFB) and modulators (silicon or III-V) with modulation up to 32 Gbits/s.
Silicon photonics has reached a considerable level of maturity, and the complexity of photonic integrated circuits (PIC) is steadily increasing. As the number of components in a PIC grows, loss management becomes more and more important. Integrated semiconductor optical amplifiers (SOA) will be crucial components in future photonic systems for loss compensation. In addition, there are specific applications, where SOAs can play a key role beyond mere loss compensation, such as modulated reflective SOAs in carrier distributed passive optical networks or optical gates in packet switching. It is, therefore, highly desirable to find a generic integration platform that includes the possibility of integrating SOAs on silicon. Various methods are currently being developed to integrate light emitters on silicon-on-insulator (SOI) waveguide circuits. Many of them use III-V materials for the hybrid integration on SOI. Various types of lasers have been demonstrated by several groups around the globe. In some of the integration approaches, SOAs can be implemented using essentially the same technology as for lasers. In this paper we will focus on SOA devices based on a hybrid integration approach where III-V material is bonded on SOI and a vertical optical mode transfer is used to couple light between SOI waveguides and guides formed in bonded III-V semiconductor layers. In contrast to evanescent coupling schemes, this mode transfer allows for a higher confinement factor in the gain material and thus for efficient light amplification over short propagation distances. We will outline the fabrication process of our hybrid components and present some of the most interesting results from a fabricated and packaged hybrid SOA.
The lack of potent integrated light emitters is one of the bottlenecks that have so far hindered the silicon photonics platform from revolutionizing the communication market. Photonic circuits with integrated light sources have the potential to address a wide range of applications from short-distance data communication to long-haul optical transmission. Notably, the integration of lasers would allow saving large assembly costs and reduce the footprint of optoelectronic products by combining photonic and microelectronic functionalities on a single chip. Since silicon and germanium-based sources are still in their infancy, hybrid approaches using III-V semiconductor materials are currently pursued by several research laboratories in academia as well as in industry. In this paper we review recent developments of hybrid III-V/silicon lasers and discuss the advantages and drawbacks of several integration schemes. The integration approach followed in our laboratory makes use of wafer-bonded III-V material on structured silicon-on-insulator substrates and is based on adiabatic mode transfers between silicon and III-V waveguides. We will highlight some of the most interesting results from devices such as wavelength-tunable lasers and AWG lasers. The good performance demonstrates that an efficient mode transfer can be achieved between III-V and silicon waveguides and encourages further research efforts in this direction.
We describe a hybrid III-V on Silicon laser designed for low noise class-A dynamics. The laser is based on an InP active region and a passive silicon region integrated in a long laser cavity. High-Q ring resonators are used as optical filters in order to achieve single frequency operation. A fiber-coupled output power of 4.6 mW and a 55 dB side mode suppression ratio are obtained. For a pumping rate of 5.2, the hybrid laser exhibits a Relative Intensity Noise below -145 dB/Hz over a wide frequency bandwidth, from 100 MHz to 40 GHz but still suffers from some noise excess due to relaxation oscillations phenomena and side modes noise. The optimization of the laser cavity design is discussed in order to reach class-A dynamics while reducing residual noise excess.
Silicon photonics is attracting large attention due to the promise of fabricating low-cost, compact circuits that integrate photonic and microelectronic elements. It can address a wide range of applications from short distance data communication to long haul optical transmission. Today, practical Si-based light sources are still missing, despite the recent demonstration of an optically pumped germanium laser. This situation has driven research to the heterogeneous integration of III-V semiconductors on silicon through wafer bonding techniques. This paper reports on recent advances on integrated hybrid InP/SOI lasers and transmitters using a wafer bonding technique made in particular at III-V Lab, France.