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ABSTRACT: We report on two techniques for the realization of expanded-mode
laser arrays with a single epitaxial growth step and conventional
fabrication techniques. Laser arrays with integrated adiabatic-mode
expanders (AME) based on a tapered active region and an underlying
passive coupling waveguide are demonstrated at the 1.55-μm
wavelength. These lasers butt couple to standard cleaved single-mode
fibers (SMF's) with a loss of only 3.6 dB. This coupling efficiency
compares with a theoretical calculation of 3.2 dB. We also propose a
novel realization of a laser with an integrated-mode expander based on
resonant coupling between a tapered active waveguide and an underlying
coupling waveguide. Three-dimensional (3-D) beam propagation method
(BPM) results are presented which show that compact, efficient mode
expanders with a mode transformation loss of only 0.36 dB can be
realized using this method. Butt-coupling efficiencies of 2.6 dB are
possible to standard cleaved single-mode fibers
IEEE Journal of Selected Topics in Quantum Electronics 01/1999; · 3.78 Impact Factor
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ABSTRACT: We demonstrate a novel expanded mode laser for enhanced laser-fiber coupling based on resonant coupling between a tapered active waveguide and an underlying coupling waveguide. This device was grown in a single standard epitaxial growth and was processed using conventional fabrication techniques, thus making it attractive for low-cost manufacturing. The total taper length required for mode transformation was 200 /spl mu/m and the excess transformation loss was 0.6 dB indicating the compact, low-loss mode transformation. Far-field divergence angles (13/spl deg//spl times/24/spl deg/) and improved coupling to cleaved single-mode fibers (3.8-dB coupling loss), were achieved.
IEEE Photonics Technology Letters 10/1998; · 2.19 Impact Factor
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ABSTRACT: 1.9-W quasi-CW output power with about 80% of the power in the central lobe is obtained from a 1.55-/spl mu/m wavelength InGaAsP-InP MQW tapered unstable resonator laser. This power is found to be emitted in a near-diffraction-limited beam.
IEEE Photonics Technology Letters 09/1998; · 2.19 Impact Factor
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ABSTRACT: A novel technique for enhanced laser-fiber coupling, based on resonant power coupling between a tapered active waveguide and an underlying coupling waveguide, is presented. Spot-sizes are transformed from 2.0/spl times/1.1 /spl mu/m in the active region to 6.0/spl times/3.1 /spl mu/m in the coupling waveguide, over a length of 200 /spl mu/m, with a mode transformation loss of only 0.36 dB. Butt-coupling efficiencies of 55% (2.6 dB loss) are estimated to standard cleaved single-mode fibers at 1.55 /spl mu/m. The proposed device requires a single epitaxial growth and conventional processing techniques, making it amenable for low-cost manufacturing.
IEEE Photonics Technology Letters 03/1998; · 2.19 Impact Factor
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ABSTRACT: The 1.55 μm wavelength window is important for future WDM systems, and hence there has been considerable interest in realizing mode expanded lasers at this wavelength. Here, we present a mode expanded laser based on a tapered ridge design, which was grown in a single epitaxial step, and required only conventional lithography and etching techniques. This device showed reduced far-field divergence angles and high coupling efficiencies to a standard cleaved single mode fiber (3.7 dB loss). To our knowledge, this is the lowest loss demonstrated in longer wavelength devices fabricated without using regrowth
Lasers and Electro-Optics Society Annual Meeting, 1997. LEOS '97 10th Annual Meeting. Conference Proceedings., IEEE; 12/1997
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ABSTRACT: We demonstrate a tapered ridge mode expanded laser with reduced far-field divergence angles (9.5/spl deg//spl times/22/spl deg/) and improved coupling to cleaved single-mode fibers (SMF) (3.7-dB coupling loss). This device was grown in a single epitaxial growth and was processed using conventional fabrication techniques, thus making it very attractive for low-cost manufacturing. This scheme also represents a general method by which active gain regions can be introduced into passive optical devices like beam splitters and combiners.
IEEE Photonics Technology Letters 12/1997; · 2.19 Impact Factor
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ABSTRACT: We have systematically studied the well number dependence of the linewidth enhancement factor in strained quantum-well (QW) lasers and have demonstrated experimentally that the linewidth enhancement factor can be reduced from /spl sim/9.4 to /spl sim/2.0 by increasing the number of compressively strained QW's from 2 to 8. This behavior is primarily due to an increase in the differential gain with the number of QW's.
IEEE Photonics Technology Letters 09/1997; · 2.19 Impact Factor
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ABSTRACT: We have developed a general method for rapidly bonding
semiconductor laser arrays, optical traveling wave amplifier arrays, and
other optoelectronic devices to silicon waferboards or submounts. Our
method uses octagonal electrodeposited copper bosses to physically
register with precision etched inverted pyramidal receptacles in the
silicon. Flip-chip bonding of semiconductor laser diode arrays is
significantly faster with this method than with a commercial precision
flip chip bonder which images the die and the substrate simultaneously
(i.e. with the “vision servo” method). The pre-bond die
placement window we obtained is compatible with certain standard flip
chip bonders. The post-bond positioning accuracy that we have
demonstrated is essential for minimizing the worst-case temperature rise
in high power semiconductor lasers and high gain traveling wave
amplifiers (TWAs) operating at high levels of current injection
Electronic Components and Technology Conference, 1997. Proceedings., 47th; 06/1997
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ABSTRACT: We report on low-loss, alignment-tolerant coupling between a single-quantum-well (SQW) GaAs-AlGaAs laser and a cleaved single-mode fiber. The laser was fabricated using conventional growth and processing techniques, and did not involve any regrowth. The mode size in the transverse direction was expanded by using a diluted waveguide structure. A butt-coupling efficiency of 66% was achieved against a theoretically possible 78% (which does not correct for Fresnel losses). In addition, large alignment tolerances for a 1-dB excess loss of /spl plusmn/2.0 pm and /spl plusmn/1.0 /spl mu/m were measured in the lateral and the transverse directions, respectively.
IEEE Photonics Technology Letters 10/1996; · 2.19 Impact Factor
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ABSTRACT: Summary form only given. Here we report on the design and operation of a high-speed monolithically integrated GaAs receiver with MSM photodetector. We also report on a packaging approach to reliably couple light from an optical fiber on to the planar detector. This approach utilizes Si V-groove technology and flip-chip bonding to achieve the required alignment tolerances.
Lasers and Electro-Optics, 1996. CLEO '96., Summaries of papers presented at the Conference on; 07/1996
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ABSTRACT: In this paper, we propose and demonstrate a simple GaAs-AlGaAs SQW
laser employing conventional growth and processing techniques. In this
laser, the transverse spot size has been increased by the use of a
diluted waveguide (Al mole fractions are graded from 30% in the core to
31% in the cladding). This laser butt-couples into a cleaved single mode
fiber with only -2.8 dB loss, and has a -3 dB excess loss misalignment
tolerance of ±3.4 μm in the lateral and ±1.6 μm in
the transverse directions. The laser showed a T<sub>0</sub> of 112 K,
indicating that the leakage of carriers is not very significant
Lasers and Electro-Optics Society Annual Meeting, 1995. 8th Annual Meeting Conference Proceedings, Volume 1., IEEE; 11/1995
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Sarnoff Symposium, 1995., IEEE Princeton Section; 05/1995
