Nonlinear adiabatic optical isolator

Abstract

We theoretically propose a method for optical isolation based on adiabatic nonlinear sum frequency generation in a chirped quasi-phase-matching crystal with strong absorption at the generated sum frequency wave. The method does not suffer from limitations of dynamic reciprocity found in other nonlinear optical isolation methods, and can provide tunable optical isolation with ultrafast all-optical switching capability. Moreover, as an adiabatic technique it is robust to variations in the optical design and is relatively broadband. c 2016 OCIS codes: 190.0190, 190.4223, 190.26201180.An optical isolator (optical diode) is the optical correspondent of electronic diode, allowing unidirectional non-reciprocal light transmission. These devices are widely used in optical telecommunications and laser applications to prevent the unwanted feedback that might be harmful to optical instruments and devices. Moreover, the use of an isolator generally improves the performance of an optical circuit as it suppresses spurious interferences, interactions between different devices and undesired light routing [1]. Currently, optical diodes rely almost exclusively on the Faraday effect where external magnetic fields are used to break time reversal symmetry [2]. However, optical isolators based on the Faraday effect are typically large-size devices, they cannot be implemented easily in on-chip integrated systems [3], and do not provide dynamic optical isolation with all-optical switching capability, which is desirable in advanced optical signal processing.Several recent works have suggested and experimentally demonstrated new ways to realize optical isolators that do not rely on magneto-optical effects [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Dynamic modulation methods, which enable tunable optical isolation with all-optical switching capabilities, have been recently proposed and experimentally demonstrated using liquid-crystal heterojunctions [7], phase modulators in InP and silicon photonics [9, 10], optoacoustic photonic crystal fibers [11], and traveling-wave Mach-Zehnder modulators [12]. A broad class of optical isolators is the one based on nonlinear interaction of light in a nonlinear medium, which breaks Lorentz reciprocity. Nonlinear optical isolators have raised great attention since more than two decades [4][5][6][13][14][15][16][17][18][19], mainly because of their all-optical switching capability exploiting the ultrafast response of the nonlinear medium and for on-chip integration possibilities. However, their effectiveness in optical isolation has been recently questioned owing of the appearance of so-called dynamical reciprocity [20]. In a nonlinear optical isolator, non-reciprocal transmission contrast is observed when strong waves are injected in forward or backward directions, however optical isolation is constrained by a reciprocity relation for a class of small-amplitude additional waves that can be transmitted.In this Letter we suggest a different route toward nonlinear optical isolation, which...

The geometric phase in nonlinear frequency conversion

“…6(a)-(b)]. This property was proposed [115] and later realized experimentally [116] as a new platform of optical isolation. By extension, the nonlinear geometric phase need also demonstrate such nonreciprocity [58][59][60], which can be employed for nonreciprocal spatial mode conversion.…”

Nonlocality-Enabled Magnetic Free Optical Isolation in Hyperbolic Metamaterials

“…With the development of integrated optics, there exists an ever-growing demand for compatible solutions for optical isolation. Over the last two decades, non-linear optical effects have been considered as promising means for optical isolation in integrated systems [ 11 , 12 , 13 , 14 ]. However, optical isolators based on non-linear materials are applicable only to high intensity signals, which often does not eliminate unwanted feedback to a sufficient degree [ 15 ].…”

Optical nonreciprocal response and conversion in a Tavis‐Cummings coupling optomechanical system

“…[42][43][44] Nonreciprocal devices based on nonreciprocity, for example, isolator, directional amplifier, circulator, and so on, play significantly important roles in quantum information processing and communication. Specifically, optical isolator is a device that blocks light in one direction but allows light to pass in the opposite direction, which has already been studied in both theory 45 and experiment. 46,47 The fabrication of low-loss and high Q optical microcavities has achieved great progress using chemo-mechanical polish lithography.…”