C-band nonlinear optical interactions in InGaAsP/InP passive waveguides

Abstract InGaAsP on InP substrates form a photonic integration platform that enables monolithic integration of active and passive components on transmitter and receiver chips. Although the current InP transceivers operate in the linear optical regime, their capabilities can be expanded by incorporating nonlinear photonic components for optical signal processing and frequency conversion. In this study, we design and fabricate In 0.86 Ga 0.14 As 0.30 P 0.70 /InP waveguides with two different geometries to measure their nonlinear coefficients within the telecom C-band. Specifically, we examine integrated photonic half-core (HC) and nanowire (NW) waveguides, consistent with various geometries used in InP monolithic integration. We conducted four-wave mixing (FWM) and nonlinear absorption measurements at a pump wavelength of 1552 nm and a tunable probe ranging from 1535 to 1565 nm. The two-photon absorption coefficient, α 2 , was measured at 19 cm GW −1 . The FWM conversion span, indicating the wavelength difference between the furthest signal and idler spectral peaks, was found to be 125 nm for HC and 95 nm for NW geometries. Additionally, the nonlinear refractive index (Kerr) coefficient, n 2 , was determined to be <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>n</mml:mi> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mstyle scriptlevel="0"/> <mml:mo>=</mml:mo> <mml:mstyle scriptlevel="0"/> <mml:mo stretchy="false">(</mml:mo> <mml:mn>1.9</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.4</mml:mn> <mml:mo stretchy="false">)</mml:mo> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>13</mml:mn> </mml:mrow> </mml:msup> <mml:mstyle scriptlevel="0"/> <mml:msup> <mml:mrow> <mml:mi>cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mstyle scriptlevel="0"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">W</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>n</mml:mi> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mo stretchy="false">(</mml:mo> <mml:mn>2.2</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.4</mml:mn> <mml:mo stretchy="false">)</mml:mo> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>13</mml:mn> </mml:mrow> </mml:msup> <mml:mstyle scriptlevel="0"/> <mml:msup> <mml:mrow> <mml:mi>cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mstyle scriptlevel="0"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">W</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> , for the TE and TM modes, marking the first reported value for the In 0.86 Ga 0.14 As 0.30 P 0.70 /InP waveguide through FWM in the telecom C-band.