Gain bandwidth of 80 nm and 2 dB/cm peak gain in Al_2O_3:Er^3+ optical amplifiers on silicon

Abstract

Erbium-doped aluminum oxide integrated optical amplifiers were fabricated on silicon substrates, and their characteristics were investigated for Er concentrations ranging from 0.27 to 4.2ϫ 10 20 cm −3 . Background losses below 0.3 dB/ cm at 1320 nm were measured. For optimum Er concentrations in the range of 1 to 2 ϫ 10 20 cm −3 , an internal net gain was obtained over a wavelength range of 80 nm ͑1500-1580 nm͒, and a peak gain of 2.0 dB/ cm was measured at 1533 nm. The broadband and high peak gain are attributed to an optimized fabrication process, improved waveguide design, and pumping at 977 nm as opposed to 1480 nm. In a 5.4-cm-long amplifier, a total internal net gain of up to 9.3 dB was measured. By use of a rate-equation model, an internal net gain of 33 dB at the 1533 nm gain peak and more than 20 dB for all wavelengths within the telecom C-band ͑1525-1565 nm͒ are predicted for a launched signal power of 1 W when launching 100 mW of pump power into a 24-cm-long amplifier. The high optical gain demonstrates that Al 2 O 3 :Er 3+ is a competitive technology for active integrated optics.

High-gain Al2O3:Nd3+ channel waveguide amplifiers at 880 nm, 1060 nm, and 1330 nm

“…Over the last two decades there has been significant interest in rare-earth-ion-doped planar waveguide amplifiers [1][2][3][4][5][6][7][8][9] for integrated optical applications. Such low-cost, compact components can be very useful for amplifying optical signals at a high data rate of 170 Gbit/s [8] and compensating optical losses owing to waveguide materials, signal routing, and input/output coupling within an integrated optical circuit.…”

“…Besides, Al 2 O 3 is compatible with Si-based technology. Previously, Er-doped Al 2 O 3 has been studied as a gain medium and a peak gain of 2 dB/cm at 1533 nm, and net gain over a wide wavelength range of 80 nm has been demonstrated [9].…”

Al<inf>2</inf>O<inf>3</inf>:Er³⁺ as a new platform for active integrated optics

“…1. Peak total gain of 9.3 dB was demonstrated in a 5.4-cm amplifier and positive gain was achieved over an 80-nm bandwidth [3]. Using a rateequation model, up to 33 dB at the peak and > 20 dB between 1525 -1565 nm is predicted in a 24-cm-long amplifier for a pump power of 100 mW [3], see Fig.…”

Potassium double tungstate waveguides with high ytterbium concentration for optical amplification

“…The noise figure represents the degradation of the signal-to-noise ratio of the signal beam after passing through the amplifier. Till date, gain bandwidth of 55-80 nm [35,36] and noise figure of 3.75 dB [37] had been demonstrated in rare-earth-ion-doped waveguide amplifiers, while typical gain bandwidth and noise figure for the SOAs are ~30-50 nm and 5-12 dB [38,39], respectively. Moreover, active cooling is essential for SOA 1.3 State-of-the-art waveguide amplifiers especially when it is bonded onto passive waveguide [9,40] whereas 15-20 dB of net gain can be achieved in rare-earth-ion-doped waveguide amplifiers without any thermal management measure [20,22,37,41].…”

“…Later development had led to 12.9 cm long Al2O3:Er 3+ waveguide amplifiers with record high 20 dB net gain [37]. In addition, high bit-rate amplification at 170 Gb/s [34], gain bandwidth over 80 nm [35] in the C-band, and peak gain per unit length of ~2.0 dB/cm [35] had been reported in Al2O3:Er 3+ . Monolithic integration of Al2O3:Er 3+ amplifier on silicon-on-insulator platform had also been demonstrated [13].…”