Lotte Jin Christiansen

Low-jitter and high-power 40-GHz all-active mode-locked lasers

A novel design strategy for the epitaxial structure of monolithic mode-locked semiconductor lasers is presented. Using an all-active design, we fabricate 40-GHz lasers generating 2.8-ps almost chirp-free pulses with record low high-frequency jitter and more than 7-mW fiber coupled output power.

Optical label swapping and packet transmission based on ASK/DPSK orthogonal modulation format in IP-over-WDM networks

We demonstrate all-optical label swapping based on SOA, EAM and HNLF for a two-level optically labeled packet using orthogonal ASK/DPSK modulation format. The ASK/DPSK packet is successfully transmitted over 80 km NZDSF.

Monolithically integrated reflective SOA-EA carrier re-modulator for broadband access nodes

We propose and experimentally demonstrate a monolithically integrated circuit composed of a reflective concatenated semiconductor optical amplifier (SOA) and electro-absorber (EA) for high bit-rate carrier re-modulation. Simultaneous erasure and re-modulation of intensity modulated (IM) signals are shown. Although the experimental results are performed at 5 Gb/s, reflective SOA-EA re-modulators have the potential for operation at higher bit-rates.

Steep and adjustable transfer functions of monolithic SOA-EA 2R regenerators

Measurements and numerical modeling of a reamplification and reshaping (2R) regenerator demonstrate a steep power transfer function with adjustable threshold. The threshold can be adjusted more than 6 dB by simple control of the reverse bias voltage of the absorber section. The device consists of a semiconductor waveguide with alternating amplifier and absorber sections using quantum-well active material. The steep nonlinearity of the transfer function is achieved by concatenating several sections. We identify the saturation properties of the absorbing media, as dictated by the band-filling and field screening, as important for the observed transfer functions. The relation of the saturation powers of the gain and absorption sections is important for design optimization.

8×40 Gb/s RZ all-optical broadcasting utilizing an electroabsorption modulator

We experimentally demonstrate all-optical broadcasting through simultaneous 8×40 Gb/s wavelength conversion using an electroabsorption modulator. The original intensity-modulated information is successfully duplicated onto eight wavelengths. The advantages of the proposed wavelength conversion scheme are discussed.

Novel design of low-jitter 10 GHz all-active monolithic mode-locked lasers

Using a novel design, we have fabricated 10 GHz all-active monolithic mode-locked semiconductor lasers that generate 1.4 ps pulses with record-low timing jitter. The dynamical properties of lasers with 1 and 2 QWs are compared.

Measurement and modeling of the transfer function of a monolithic SOA-EA 2R-regenerator

We have measured steep power transfer characteristics with tunable threshold for a monolithic 2R-regenerator combining amplifying and absorbing sections. Modeling results explain the basic characteristics.