Charles H. Joyner

Large-scale photonic integrated circuits

We present an overview of Infineras current generation of 100 Gb/s transmitter and receiver PICs as well as results from the next-generation 500 Gb/s PM-QPSK PICs.

LARnet, a local access router network

A novel local access network, LARNet, is proposed and demonstrated. A multifrequency laser, whose wavelength COMB94 is matched to that of a passive waveguide router in the remote node, is used as a downstream signal source. A 1.3-/spl mu/m commercially available LED provides the upstream signal. LARNet solves a major problem of WDM networks, the spectral alignment between the optical wavelengths of different channels. Furthermore. The expensive components are shared among all subscribers. Our measurements indicate that aggregate rates of 2 Gbps downstream and 155 Mbps upstream are feasible.<<ETX>>

Acceleration of gain recovery in semiconductor optical amplifiers by optical injection near transparency wavelength

By using optical injection near the transparency wavelength of semiconductor optical amplifiers, we show experimentally that both the saturation output power and the gain recovery can be greatly improved. By injecting 80 mW of pump power, we observe a 3-dB increase in saturation output power. For 73 mW of pump power, we find a reduction in gain recovery time from over 200 ps down to below 40 ps, while maintaining 14 dB of fiber-to-fiber gain at 1555-nm wavelength.

Multimode interference couplers with tunable power splitting ratios

New, compact multimode interference couplers with tunable power splitting ratios have been realized. Experiments show large tuning ranges. Such couplers are needed to optimize ON-OFF ratios in interferometric devices and may find applications as extremely compact switches.

Demonstration of a 15*15 arrayed waveguide multiplexer on InP

By interconnecting two star couplers with a waveguide grating, the authors built a monolithic 15*15 multiplexer on InP. The grating order of 148 gives a free spectral range of 10.5 nm (1.3 THz) and a channel spacing of 0.7 nm (87 GHz) at 1550 nm wavelength. A crosstalk between adjacent channels of less than 18 dB and a residual crosstalk of less than 25 dB were obtained. The on-chip insertion loss is typically 2-4 dB.<<ETX>>

An 18-channel multifrequency laser

A multifrequency laser (MFL) is demonstrated that runs simultaneously CW on 18 channels spaced by 103 GHz. The laser emits -14.6-dBm power per wavelength channel into single-mode fiber. Each wavelength channel can be modulated at 1.24 Gb/s. The MFL exhibits a stable and reproducible optical channel spacing owing to the reproducibility of the waveguide grating router that serves as the intracavity filter element.

InP Photonic Integrated Circuits

InP is an ideal integration platform for optical generation, switching, and detection components operating in the range of 1.3-1.6 m wavelength, which is preferred for data transmission in the most prevalent silica-based optical fiber. We review the current state of the art in advanced InP photonic ICs.

Digitally tunable channel dropping filter/equalizer based on waveguide grating router and optical amplifier integration

We demonstrate a novel and powerful device that permits individual and simultaneous control of all the wavelength channels in a WDM system. The device is based on the monolithic integration of two identical waveguide grating routers with semiconductor optical amplifiers. By biasing appropriately the individual amplifier, each WDM channel can be amplified, detected or modulated. The device exhibits a channel bandwidth of 60 GHz, a channel spacing of 195 GHz and a crosstalk of /spl minus/19 dB.<<ETX>>

Narrowband grating resonator filters in InGaAsP/InP waveguides

We report the first demonstration of efficient narrowband optical wavelength filters using InGaAsP/InP passive waveguide grating resonators. Filter bandwidths as narrow as 1 A, centered about λ=1.55 μm with excess resonator loss as low as 1 dB, have been achieved.

Digitally tunable laser based on the integration of a waveguide grating multiplexer and an optical amplifier

A novel monolithic semiconductor laser is demonstrated. The optical cavity comprises a 1/spl times/N waveguide grating multiplexer connected to N optical amplifiers. By driving a specific output port, laser oscillation is obtained at the wavelength determined by the wavelength path through the multiplexer. Such a laser is very useful for WDM systems because it is capable of producing a comb of precisely spaced frequencies.<<ETX>>