Copyright (c) 2009 All rights reserved. http://works.bepress.com/ddericks Recent documents in Dennis Derickson en-us Sun, 31 May 2009 05:16:36 PDT 3600 http://works.bepress.com/ddericks/32 http://works.bepress.com/ddericks/32 Wed, 06 May 2009 11:14:03 PDT Electrooptic modulators built from GaAs/AlxGa1-xAs Fabry-Perot cavities operating up to 6.5 GHz are reported. The measured frequency response agrees well with the one predicted using an equivalent circuit model derived from high-speed electrical measurements. The parasitic capacitances have been reduced to approximately 30 fF by fabricating the devices on semi-insulating GaAs substrates and integrating them with on-wafer bound pads which have dimensions compatible with microwave coplanar probes. R. J. Simes Articles http://works.bepress.com/ddericks/31 http://works.bepress.com/ddericks/31 Wed, 06 May 2009 11:14:02 PDT Dennis J. Derickson Articles http://works.bepress.com/ddericks/30 http://works.bepress.com/ddericks/30 Wed, 06 May 2009 11:14:01 PDT Dennis J. Derickson Articles http://works.bepress.com/ddericks/28 http://works.bepress.com/ddericks/28 Wed, 06 May 2009 11:14:00 PDT A new mode-locking technique, self-mode-locking, is described which uses the detected optical pulses from the mode-locked laser as the active driving source. This technique forms narrow-width mode-locked optical pulses at low repetition rates without the use of a microwave synthesizer Dennis J. Derickson Articles http://works.bepress.com/ddericks/27 http://works.bepress.com/ddericks/27 Wed, 06 May 2009 11:13:59 PDT A comprehensive timing jitter comparison is made for mode-locked semiconductor lasers using active, passive, and hybrid mode-locking techniques in both external and monolithic cavity configurations. Active mode locking gives the lowest residual rms timing jitter of 65 fs (150 Hz-50 MHz), followed by the hybrid and passive mode-locking techniques. It is found that monolithic cavity devices with all active waveguides have higher timing jitter levels than the comparable external cavity case. Dennis J. Derickson Articles http://works.bepress.com/ddericks/26 http://works.bepress.com/ddericks/26 Wed, 06 May 2009 11:13:58 PDT Imperfect antireflection coatings in external-cavity mode-locked semiconductor lasers can cause multiple output pulse generation. The incorporation of an intrawaveguide saturable absorber segment into the laser suppresses this problem. Single pulse outputs of less than 2.8 ps and 0.7 pJ of energy are obtained using such devices with both quantum well and bulk active regions Dennis J. Derickson Articles http://works.bepress.com/ddericks/25 http://works.bepress.com/ddericks/25 Wed, 06 May 2009 11:13:57 PDT Mode-locked vertical cavity lasers have a large cross-sectional area and consequently a large saturation energy and large peak powers. The authors analyze excess optical bandwidth generation in these lasers and find that self-phase modulation due to optical pumping and gain saturation is the dominant factor in inducing laser pulse chirping. The large magnitude of the chirp makes intracavity prism-pair compensation difficult. Adjustment of the cavity length has a major impact on the pulse chirping, as observed experimentally. Proper adjustment can result in a large linear frequency chirp which can be compensated using external pulse compression techniques Wenbin Jiang Articles http://works.bepress.com/ddericks/24 http://works.bepress.com/ddericks/24 Wed, 06 May 2009 11:13:56 PDT The repetition frequency of an external cavity mode-locked GaAs semiconductor diode laser has been stabilized by voltage controlled electrical feedback. The phase noise has been reduced by 40dB at 1 kHz offset from the carrier and timing jitter reduced from more than 30ps to 4ps. This technique can be used to stabilize millimetre-wave mode-locked lasers. R. J. Helkey Articles http://works.bepress.com/ddericks/23 http://works.bepress.com/ddericks/23 Wed, 06 May 2009 11:13:56 PDT A report is presented on the design, fabrication, testing, and modeling of single-heterojunction Al0.27Ga0.73As/Ga p-i-n photodiodes for use as components in optical receivers. The photodiodes are grown by molecular beam epitaxy and fabricated as 1100-μm2 mesa structures. At 5-V reverse bias and 850 nm, 100 fF of capacitance, 90 pA of leakage current, 73% external quantum efficiency, <2% reflectivity, and 22-GHz bandwidths are typically measured. C. Johnson Articles http://works.bepress.com/ddericks/22 http://works.bepress.com/ddericks/22 Wed, 06 May 2009 11:13:55 PDT Absorption recovery dynamics of GaAs/AlGaAs field-enhanced waveguide saturable absorbers are studied by pump-probe differential transmission measurements. We compare the response of bulk and single quantum well absorbers at different reverse bias levels and pump powers, and find an ultrafast transient in the response, followed by a slower rise before the final recovery. The absorption fully recovers after a few picoseconds, which is an important result for mode-locked lasers. J. R. Karin Articles