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Nonlinear equalization of microwave photonic links

Published in:
IEEE Int. Topical Meeting on Microwave Photonics, MWP 2016, 31 October - 3 November 2016.

Summary

High dynamic range is a key requirement in advanced microwave photonic systems. We demonstrate compensation of nonlinearities occurring in microwave photonic links using a novel digital nonlinear equalization technique and demonstrate suppression of distortion products by 33 dB with a small number of equalizer coefficients.
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Summary

High dynamic range is a key requirement in advanced microwave photonic systems. We demonstrate compensation of nonlinearities occurring in microwave photonic links using a novel digital nonlinear equalization technique and demonstrate suppression of distortion products by 33 dB with a small number of equalizer coefficients.

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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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Super-homogenous saturation of microwave-photonic gain in optoeletronic oscillator systems

Published in:
IEEE Photonics J., Vol. 4, No. 5, October 2012, pp. 1256-1266.
Topic:

Summary

We show that the saturation characteristic of microwave-photonic gain is "superhomogeneous" such that the gain of a weaker tone saturates more rapidly than that of a stronger tone when both signals are transmitted over an intensity-modulated optical link. Using this gain model, we simulate the effect of nonlinear gain saturation on the performance of a slab-coupled optical waveguide (SCOW)-based optoelectronic oscillator (OEO). We verify our simulations with experimental measurements and show that low sidemode levels (< -110 dBc) can be achieved even when multiple modes can oscillate within the passband of the OEO loop filter.
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Summary

We show that the saturation characteristic of microwave-photonic gain is "superhomogeneous" such that the gain of a weaker tone saturates more rapidly than that of a stronger tone when both signals are transmitted over an intensity-modulated optical link. Using this gain model, we simulate the effect of nonlinear gain saturation...

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High dynamic range suppressed-bias microwave photonic links using unamplified semiconductor laser source

Published in:
AVFOP 2012: IEEE Avionics, Fiber-Optics and Photonics Tech. Conf., 11-13 September 2012, pp. 28-9.
Topic:
R&D group:

Summary

Microwave photonic (MWP) links with a low noise figure and high dynamic range are required for antenna remoting, radio-over-fiber (RoF), and other advanced applications. MWP links have recently been demonstrated with noise figures approaching 3 dB, without any electrical preamplification, by using low-noise high-power laser sources in conjunction with efficient optical intensity modulators and high-power photodetectors. An alternate approach to noise figure reduction, suitable for sub-octave links, is based on using a high-power laser source and shifting the bias point of an external optical intensity modulator to reduce the average photocurrent and suppress excess link noise. Here, we report the performance of a novel slab-coupled optical waveguide external-cavity laser (SCOWECL) in a suppressed bias MWP link. We compare the performance of this link with a suppressed-bias link using a source comprising a commercial-off-the-shelf (COTS) laser and erbium-doped fiber amplifier (EDFA) and show that MWP links built using SCOW-based emitter technology offer superior performance due to the small-form factor, high-efficiency, low-noise, and high power laser source.
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Summary

Microwave photonic (MWP) links with a low noise figure and high dynamic range are required for antenna remoting, radio-over-fiber (RoF), and other advanced applications. MWP links have recently been demonstrated with noise figures approaching 3 dB, without any electrical preamplification, by using low-noise high-power laser sources in conjunction with efficient...

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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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Impact of semiconductor optical amplifiers in coherent down-conversion microwave photonic links

Published in:
CLEO: Conf. on Lasers and Electro-Optics, 6-11 June 2012.
Topic:
R&D group:

Summary

We compare the impact of conventional semiconductor optical amplifiers (SOAs) and high linearity slab-coupled optical waveguide amplifiers (SCOWAs) on the SFDR of carrier-suppressed coherent down-conversion microwave photonic links.
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Summary

We compare the impact of conventional semiconductor optical amplifiers (SOAs) and high linearity slab-coupled optical waveguide amplifiers (SCOWAs) on the SFDR of carrier-suppressed coherent down-conversion microwave photonic links.

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Waveguide engineering for hybrid Si/III-V lasers and amplifiers

Published in:
CLEO: Conf. on Lasers and Electro-Optics, 6-11 June 2012.

Summary

Using adiabatic tapers, hybrid silicon / III-V lasers and amplifiers are integrated with conventional thin (t = 0.25 um) silicon waveguides. Amplifiers have ~12 dB intrachip gain, and similar lasers have thresholds of 35 mA.
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Summary

Using adiabatic tapers, hybrid silicon / III-V lasers and amplifiers are integrated with conventional thin (t = 0.25 um) silicon waveguides. Amplifiers have ~12 dB intrachip gain, and similar lasers have thresholds of 35 mA.

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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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Compact external-cavity semiconductor mode-locked laser with quantum-well-intermixed modulator and saturable absorber

Published in:
IPC11, IEEE Photonics Conf., 9-13 October 2011, pp. 753-754.

Summary

We demonstrate a slab-coupled optical waveguide external-cavity mode-locked laser having unique bandedges for the amplifier, modulator and saturable absorber elements. An average output power of 50mW and timing jitter of 254fs is achieved at 1.5-GHz.
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Summary

We demonstrate a slab-coupled optical waveguide external-cavity mode-locked laser having unique bandedges for the amplifier, modulator and saturable absorber elements. An average output power of 50mW and timing jitter of 254fs is achieved at 1.5-GHz.

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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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