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ABSTRACT: We investigate theoretically and experimentally the effect of the physical length of gain medium on dynamic mode stability in semiconductor lasers with an intra-cavity filter. In simulation, two types of analysis models were used to examine the lasing properties and to analyze the dynamic mode stability of the external-cavity system, respectively. In experiment, two different kinds of the structures were fabricated and their spectra were analyzed. Both simulation and measurement results show clearly the length of the gain medium has a critical influence on the stability around the peak wavelength of the filter.
Optics Express 12/2009; 17(25):22838-46. · 3.59 Impact Factor
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ABSTRACT: All-optical wavelength conversion at 10 Gb s−1 is demonstrated in a Mach–Zehnder interferometric wavelength converter (MZI-WC) module with monolithically integrated SOA preamplifiers and tapered-edge multimode interference couplers (TMMIs). A conventional buried-type 1 × 2 MMI coupler exhibits a minimal excess loss of 0.43 dB and a reflectivity of 5.1 × 10−4 (LMMI = 172 µm, WMMI = 12 µm). We adapt the 1 × 2 TMMI in the MZI-WC to improve back-reflection and poor uniformity, which is a major problem of conventional MMI and Y-branch. A good performance of the MZI-WC monolithically integrated with TMMI and SOA preamplifiers at 10 Gb s−1 is obtained with clear eye patterns, and a power penalty below 1.5 dB at a 10−9 bit error rate over the whole C band (45 nm span) is obtained. The dynamic input power range is enhanced up to 11.3 dB by adjusting only the injection current of the SOA preamplifier.
Semiconductor Science and Technology 09/2006; 21(10):1478. · 1.72 Impact Factor
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ABSTRACT: A widely tunable grating cavity laser based on the Rowland circle construction for a concave grating is proposed and demonstrated. The device is implemented by employing multichannel array structure in a Littman configuration and fabricated by integrating all elements in an InP substrate. Only one channel is turned on at a time, with coarse tuning realized by selecting the appropriate element in the channel array and fine tuning by controlling the beam deflection provided by dispersive element. An overall tuning range of 50 nm with a sidemode suppression ratio of more than 30 dB has been achieved for the six-channel device
IEEE Photonics Technology Letters 09/2006; · 2.19 Impact Factor
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ABSTRACT: We demonstrate simultaneous optical clock extraction and wavelength-conversion from NRZ in MZ-IWC. PRZ extracted from pump using optical filter. By injection-locking self-pulsation LD using PRZ, optical clock obtained. Simultaneously, we obtained wavelength-converted signal from probe.
Optical Internet and Next Generation Network, 2006. COIN-NGNCON 2006. The Joint International Conference on; 08/2006
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ABSTRACT: A lensless tunable external-cavity laser diode monolithically integrated with InP-based planar waveguide parabolic-shaped collimating lens, optical deflector, and echelle grating is proposed and demonstrated in this work. The tunable laser exhibits a total wavelength tuning range of 9.3 nm with a side mode suppression ratio of about 35 dB by adjusting the applied current of optical deflectors and phase control section.
Applied Physics Letters 11/2005; 87(22):221112-221112-3. · 3.84 Impact Factor
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ABSTRACT: We propose a novel external-cavity tunable laser realized by monolithically integrating a semiconductor optical amplifier, a phase-control section, a dispersive element, and an etched diffraction grating in InP. The tuning operation is based on electrically controlled deflection of the propagating beam through the dispersive element while the grating offers to select a specific wavelength. With the electrical control, the continuous wavelength tuning of 11 nm with a side mode suppression ratio of more than 35 dB has been successfully achieved.
Optical Communication, 2005. ECOC 2005. 31st European Conference on; 10/2005
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ABSTRACT: A novel lensless tunable external cavity laser diode monolithically integrated with InP-based planar waveguide parabolic-shaped collimating lens, optical deflector and echelle grating is proposed and demonstrated in this work. The tunable laser exhibits total wavelength tuning range of 9.3 nm and quasi-continuous tuning (0.05 nm) with high SMSR as high as 40 dB by adjusting applied current of optical deflectors and phase control section.
Optical Communication, 2005. ECOC 2005. 31st European Conference on; 10/2005
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ABSTRACT: Amplified spontaneous emission (ASE) spectra of passive waveguide integrated lasers have been studied to estimate the coupling efficiency and the reflectivity at the butt-joints between active and passive waveguides. A new method has been proposed for the analysis of ASE to extract the coupling efficiency and reflectivity at the butt-joints. This method was applied experimentally to estimate the coupling and reflection of the passive waveguide integrated lasers with different amounts of vertical misalignments of active and passive waveguides.
IEEE Photonics Technology Letters 10/2005; · 2.19 Impact Factor
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ABSTRACT: A multiwavelength grating cavity laser is reported using a novel design for a multichannel light source based on an etched diffraction grating. Following the design, the compact eight-channel device capable of fine-tuning has been realized by monolithically integrating semiconductor optical amplifiers, various passive waveguides, and deeply etched grating, providing high butt-coupling efficiency, and low waveguide losses. As a result, the sidemode suppression ratio in excess of 45 dB over all channels was achieved.
IEEE Photonics Technology Letters 10/2005; · 2.19 Impact Factor
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ABSTRACT: A novel grating cavity tunable laser is proposed and experimentally demonstrated. It is realized by monolithically integrating a semiconductor optical amplifier, a dispersive element, a phase-control section, and an etched diffraction grating in a single chip. Tuning operation is based on electrically controlled beam deflection provided by dispersive element and phase matching by phase-control section. With the electrical control, the wavelength tuning of 8.5 nm with a sidemode suppression ratio of about 35 dB has been successfully achieved.
IEEE Photonics Technology Letters 10/2005; · 2.19 Impact Factor
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ABSTRACT: Using a calculation of overlap integral loss of waveguide mirror was analyzed. According to this analysis method, a taper section was introduced and loss of deep ridge waveguide mirror was improved by 1.1 dB. Analysis shows that the most significant source of loss is the bevel angle of mirror facet. Also, using this method, improvement of fabrication yield and uniformity was obtained. This analysis and design method can be applied to mirrors for integrated photonic circuits and optical printed circuit board.
IEEE Photonics Technology Letters 05/2005; · 2.19 Impact Factor
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ABSTRACT: Tunable external-cavity lasers with low power variation over a broad tuning range are demonstrated using asymmetric multiple quantum-wells with a wide and flat gain. For a 2.8-μm-wide ridge waveguide laser of cavity length 380 μm, when used in a grating external cavity and with an antireflection coating on one facet of laser diode chip, the power variation of less than -1 dB is obtained over a range of 80 nm. This extremely low power variation is a direct result of the spectrally flat gain.
IEEE Photonics Technology Letters 04/2005; · 2.19 Impact Factor
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ABSTRACT: We propose and demonstrate a novel tunable external-cavity laser diode that simultaneously achieves rapid tuning rate and wide tuning range by electrical control. This contains new-type integrated laser diode, collimating lens, and diffraction grating mirror. The integrated laser diode consists of Fabry-Pe´rot laser diode and waveguide-type deflector, which can deflect the beam passing through the waveguide. By control of the current in the deflector region, maximum wavelength variation of 8.6 nm and sidemode suppression ratio of >35 dB were obtained.
IEEE Photonics Technology Letters 09/2004; · 2.19 Impact Factor
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ABSTRACT: We demonstrated monolithic integration of a continuous wave probe source consisting of a loss-coupled distributed feedback laser diode (DFB LD) and a Mach–Zehnder interferometric wavelength converter. The integrated device was fabricated using a modified buried ridge stripe (BRS) structure with an undoped InP clad layer on the top of a passive waveguide to reduce high propagation loss. A propagation loss in the passive waveguide as low as 5.29 ± 0.92 dB cm−1 was achieved. For the first time, wavelength conversion at 10 Gb s−1 was achieved with an extinction ratio of 7 dB and a power penalty of 2.8 dB at a 10−9 bit error rate. The proposed BRS structure is very useful for fabrication of photonic integrated circuits consisting of monolithic integration of active and passive waveguides.
Semiconductor Science and Technology 02/2004; 19(5):574. · 1.72 Impact Factor
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ABSTRACT: Asymmetric multiple-quantum-well laser diodes with wide and flat gain spectra were designed, fabricated, and analyzed. The active layer was composed of three 10-nm, one 8-nm, and two 6-nm 0.5% compressive strained wells and four 10-nm and one 5-nm 0.4% tensile strained barrier layer. Measured spectra of antireflection-coated ridge waveguide laser diodes with such quantum-well structures have shown that -1-dB spectral gain bandwidth can be as large as 90 nm.
Optics Letters 12/2003; 28(22):2189-91. · 3.40 Impact Factor
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ABSTRACT: Attenuation of a deep-ridge waveguide turning mirror is analyzed using a simple overlap integral calculation. According to this analysis, loss of the fabricated mirror was improved by 1.1 dB and uniformity was also improved. Our analysis shows that more reduction of attenuation can be made by using the steep mirror facet through an optimization of the dry etch condition. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 428–431, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10939
Microwave and Optical Technology Letters 04/2003; 37(6):428 - 431. · 0.62 Impact Factor
