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Slab-coupled optical waveguide (SCOW) devices and photonic integrated circuits (PICs)

Summary

We review recent advances in the development of slab-coupled optical waveguide (SCOW) devices, progress toward a flexible photonic integration platform containing both conventional high-confinement and SCOW ultra-low confinement devices, and applications of this technology.
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Summary

We review recent advances in the development of slab-coupled optical waveguide (SCOW) devices, progress toward a flexible photonic integration platform containing both conventional high-confinement and SCOW ultra-low confinement devices, and applications of this technology.

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Amplifier-free slab-coupled optical waveguide optoelectronic oscillator systems

Published in:
Opt. Express, Vol. 20, No. 17, 13 August 2012, pp. 19589-19598.
Topic:

Summary

We demonstrate a free-running 3-GHz slab-coupled optical waveguide (SCOW) optoelectronic oscillator (OEO) with low phase-noise (88 dB down from carrier). The SCOW-OEO uses highpower low-noise SCOW components in a single-loop cavity employing 1.5- km delay. The noise properties of our SCOW external-cavity laser (SCOWECL) and SCOW photodiode (SCOWPD) are characterized and shown to be suitable for generation of high spectral purity microwave tones. Through comparisons made with SCOW-OEO topologies employing amplification, we observe the sidemode levels to be degraded by any amplifiers (optical or RF) introduced within the OEO cavity.
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Summary

We demonstrate a free-running 3-GHz slab-coupled optical waveguide (SCOW) optoelectronic oscillator (OEO) with low phase-noise (88 dB down from carrier). The SCOW-OEO uses highpower low-noise SCOW components in a single-loop cavity employing 1.5- km delay. The noise properties of our SCOW external-cavity laser (SCOWECL) and SCOW photodiode (SCOWPD) are characterized...

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High-power, low-noise 1.5-um slab-coupled optical waveguide (SCOW) emitters: physics, devices, and applications

Summary

We review the development of a new class of high-power, edge-emitting, semiconductor optical gain medium based on the slab-coupled optical waveguide (SCOW) concept. We restrict the scope to InP-based devices incorporating either InGaAsP or InGaAlAs quantum-well active regions and operating in the 1.5-μm-wavelength region. Key properties of the SCOW gain medium include large transverse optical mode dimensions (>;5 × 5 μm), ultralow optical confinement factor (Γ ~ 0.25-1%), and small internal loss coefficient (α i ~ 0.5 cm-1). These properties have enabled the realization of 1) packaged Watt-class semiconductor optical amplifiers (SOAs) having low-noise figure (4-5 dB), 2) monolithic passively mode-locked lasers generating 0.25-W average output power, 3) external-cavity fiber-ring actively mode-locked lasers exhibiting residual timing jitter of
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Summary

We review the development of a new class of high-power, edge-emitting, semiconductor optical gain medium based on the slab-coupled optical waveguide (SCOW) concept. We restrict the scope to InP-based devices incorporating either InGaAsP or InGaAlAs quantum-well active regions and operating in the 1.5-μm-wavelength region. Key properties of the SCOW gain...

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Packaged, high-power, narrow-linewidth slab-coupled optical waveguide external cavity laser (SCOWECL)

Published in:
IEEE Photonics Technol. Lett., Vol. 23, No. 14, 15 July 2011.
Topic:

Summary

We report the demonstration of an InGaAlAs/InP quantum-well, high-power, low-noise packaged semiconductor external cavity laser (ECL) operating at 1550 nm. The laser comprises a double-pass, curved-channel slab-coupled optical waveguide amplifier (SCOWA) coupled to a narrow-bandwidth (2.5 GHz) fiber Bragg grating passive cavity using a lensedfiber. At a bias current of 4 A, the ECL produces 370 mW of fiber-coupled output power with a Voigt lineshape having Gaussian and Lorentzian linewidths of 35 kHz and 1 kHz, respectively, and relative intensity noise < -160 dB/Hz from 200 kHz to 10 GHz.
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Summary

We report the demonstration of an InGaAlAs/InP quantum-well, high-power, low-noise packaged semiconductor external cavity laser (ECL) operating at 1550 nm. The laser comprises a double-pass, curved-channel slab-coupled optical waveguide amplifier (SCOWA) coupled to a narrow-bandwidth (2.5 GHz) fiber Bragg grating passive cavity using a lensedfiber. At a bias current of...

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Uni-traveling-carrier variable confinement waveguide photodiodes

Summary

Uni-traveling-carrier waveguide photodiodes (PDs) with a variable optical confinement mode size transformer are demonstrated. The optical mode is large at the input for minimal front-end saturation and the mode transforms as the light propagates so that the absorption profile is optimized for both high-power and high-speed performance. Two differently designed PDs are presented. PD A demonstrates a 3-dB bandwidth of 12.6 GHz, and saturation currents of 40 mA at 1 GHz and 34 mA at 10 GHz. PD B demonstrates a 3-dB bandwidth of 2.5 GHz, a saturation current greater than 100 mA at 1 GHz, a peak RF output power of + 19 dBm, and a third-order output intercept point of 29.1 dBm at a photocurrent of 60 mA.
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Summary

Uni-traveling-carrier waveguide photodiodes (PDs) with a variable optical confinement mode size transformer are demonstrated. The optical mode is large at the input for minimal front-end saturation and the mode transforms as the light propagates so that the absorption profile is optimized for both high-power and high-speed performance. Two differently designed...

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Microwave photonic applications of slab-coupled optical waveguide devices

Published in:
2010 23rd Annual Mtg. of the IEEE Photonics Society, 10 November 2010, pp. 479-480.
Topic:

Summary

The semiconductor slab-coupled optical waveguide (SCOW) concept is a versatile device platform that has enabled new classes of high-power, low-noise single-frequency lasers, mode-locked lasers, optical amplifiers, and photodiodes for analog optical links and photonic analog-to-digital converters.
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Summary

The semiconductor slab-coupled optical waveguide (SCOW) concept is a versatile device platform that has enabled new classes of high-power, low-noise single-frequency lasers, mode-locked lasers, optical amplifiers, and photodiodes for analog optical links and photonic analog-to-digital converters.

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Arrays of InP-based avalanche photodiodes for photon counting

Summary

Arrays of InP-based avalanche photodiodes (APDs) with InGaAsP absorber regions have been fabricated and characterized in the Geiger mode for photon-counting applications. Measurements of APDs with InGaAsP absorbers optimized for 1.06 um wavelength show dark count rates (DCRs)
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Summary

Arrays of InP-based avalanche photodiodes (APDs) with InGaAsP absorber regions have been fabricated and characterized in the Geiger mode for photon-counting applications. Measurements of APDs with InGaAsP absorbers optimized for 1.06 um wavelength show dark count rates (DCRs)

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InGaAsP/InP quantum-well electrorefractive modulators with sub-volt V[pi]

Published in:
SPIE Vol. 5435, Enabling Photonic Technologies for Aerospace Applications VI, 12-16 April 2004, pp. 53-63.

Summary

Advanced analog-optical sensor, signal processing and communication systems could benefit significantly from wideband (DC to > 50 GHz) optical modulators having both low half-wave voltage (V[pi]) and low optical insertion loss. An important figure-of-merit for modulators used in analog applications is TMAX/V[pi], where TMAX is the optical transmission of the modulator when biased for maximum transmission. Candidate electro-optic materials for realizing these modulators include lithium niobate (LiNbO3), polymers, and semiconductors, each of which has its own set of advantages and disadvantages. In this paper, we report the development of 1.5-um-wavelength Mach-Zehnder modulators utilizing the electrorefractive effect in InGaAsP/InP symmetric, uncoupled semiconductor quantum-wells. Modulators with 1-cm-long, lumped-element electrodes are found to have a push-pull V[pi] of 0.9V (V[pi]L = 9 V-mm) and 18-dB fiber-to-fiber insertion loss (TMAX/V[pi] = 0.018). Fabry-Perot cutback measurements reveal a waveguide propagation loss of 7 dB/cm and a waveguide-to-fiber coupling loss of 5 dB/facet. The relatively high propagation loss results from a combination of below-bandedge absorption and scattering due to waveguide-sidewall roughness. Analyses show that most of the coupling loss can be eliminated though the use of monolithically integrated invertedtaper optical-mode converters, thereby allowing these modulators to exceed the performance of commercial LiNbO3 modulators (TMAX/V[pi] ~ 0.1). We also report the analog modulation characteristics of these modulators.
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Summary

Advanced analog-optical sensor, signal processing and communication systems could benefit significantly from wideband (DC to &gt; 50 GHz) optical modulators having both low half-wave voltage (V[pi]) and low optical insertion loss. An important figure-of-merit for modulators used in analog applications is TMAX/V[pi], where TMAX is the optical transmission of the...

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Optically sampled analog-to-digital converters

Published in:
IEEE Trans. Microw. Theory Tech., Vol. 49, No. 10, October 2001, pp. 1840-1853.
Topic:

Summary

Optically sampled analog-to-digital converters (ADCs) combine optical sampling with electronic quantization to enhance the performance of electronic ADCs. In this paper, we review the prior and current work in this field, and then describe our efforts to develop and extend the bandwidth of a linearized sampling technique referred to as phase-encoded optical sampling. The technique uses a dual-output electrooptic sampling transducer to achieve both high linearity and 60-dB suppression of laser amplitude noise. The bandwidth of the technique is extended by optically distributing the post-sampling pulses to an array of time-interleaved electronic quantizers. We report on the performance of a 505-MS/s (megasample per second) optically sampled ADC that includes high-extinction LiNbO(3) 1-to-8 optical time-division demultiplexers. Initial characterization of the 505-MS/s system reveals a maximum signal-to-noise ratio of 51 dB (8.2 bits) and a spur-free dynamic range of 61 dB. The performance of the present system is limited by electronic quantizer noise, photodiode saturation, and preliminary calibration procedures. None of these fundamentally limit this sampling approach, which should enable multigigahertz converters with 12-b resolution. A signal-to-noise analysis of the phase-encoded sampling technique shows good agreement with measured data from the 505-MS/s system.
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Summary

Optically sampled analog-to-digital converters (ADCs) combine optical sampling with electronic quantization to enhance the performance of electronic ADCs. In this paper, we review the prior and current work in this field, and then describe our efforts to develop and extend the bandwidth of a linearized sampling technique referred to as...

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