Planar monomode optical couplers based on multimode interference effects

Soldano, LB; Veerman, FB; Smit, M.K.; Verbeek, B.H.; Dubost, A.H.; Pennings, E.C.M.

doi:10.1109/50.202837

Cited by 162 publications

(78 citation statements)

References 9 publications

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“…This design uses symmetric Y-shaped ͑or T-shaped͒ WG splitters to ensure equal light phase shifts through each of the arms, an approach that can be extended to devices with N P =2 m arms ͑m is an integer͒. Devices with an arbitrary number of arms can be realized, e.g., using multimode interference ͑MMI͒ couplers, 13 as illustrated in Fig. 1͑c͒ for N P = 3.…”

Section: Device Conceptsmentioning

confidence: 99%

Acousto-optical multiple interference devices

Beck

Lima

Santos

2008

Journal of Applied Physics

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We present a new concept for waveguide acousto-optical devices based on coupled Mach-Zehnder interferometers driven by acoustic waves. These acousto-optical multiple interference devices use the periodic refractive index modulation induced by the acoustic wave to realize functionalities such as ON/OFF switching for an arbitrary time interval, as well as for efficient light modulation at high harmonics of the acoustic frequency and pulse shaping for, e.g., integrated Q-switches. We also discuss application of the concepts to light modulation by very high acoustic frequencies, where the acoustic wavelengths become much shorter than the optical ones.

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Section: Device Conceptsmentioning

confidence: 99%

Acousto-optical multiple interference devices

Beck

Lima

Santos

2008

Journal of Applied Physics

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“…The devices with N P = 3, 5, and 6 employed multimode interference ͑MMI͒ couplers. 9 In this case, the width of the individual WGs was adjusted to ensure the same overall light phase shift through each WG arm. The AOMIDs were fabricated in two steps using contact optical lithography.…”

mentioning

confidence: 99%

Acousto-optical multiple interference switches

Beck

Lima

Wiebicke

et al. 2007

Applied Physics Letters

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The authors introduce an alternative approach for acousto-optical light control based on the interference of light propagating through several waveguides, each subjected to a periodic refractive index modulation induced by a surface acoustic wave. The feasibility of the concept is demonstrated by the realization of an optical switch for arbitrary time intervals with an on/off contrast ratio of 20. © 2007 American Institute of Physics. ͓DOI: 10.1063/1.2768889͔The acousto-optical interaction provides a wellestablished process for controlling light beams in solids. 1 With the advent of integrated optics, approaches have been sought after to implement the required phase matching between the acoustic and optical waves propagating in waveguide ͑WG͒ structures. Examples are the acoustically induced coupling between neighboring WGs ͑Ref. 1͒ and the use of Umklapp scattering in photonic crystals. 2,3 As an alternative approach, Gorecki et al. proposed the combination of surface acoustic waves ͑SAWs͒ with MachZehnder interferometers ͑MZIs͒ for WG modulators. 4,5 Here, the strain field of a SAW impinging perpendicularly to one of the interferometer arms introduces a periodic modulation of the transmitted light. More recently, de Lima et al. 6 introduced an approach for acoustically driven MZI, where a single SAW simultaneously modulates the refractive index of both MZI arms with opposite phases, as illustrated in Fig. 1͑a͒. The opposite phase modulation of amplitude max per arm is achieved by simply spacing the WGs by an odd multiple of the half acoustic wavelength SAW .In this letter, we demonstrate an alternative concept for WG acousto-optical elements based on the modulation of several interferometer arms by a single SAW beam. These acousto-optic multiple interference devices ͑AOMIDs͒ provide integrated optics building blocks for functionalities such as switching, harmonic generation, and pulse shaping. 7 The feasibility of the AOMID concept is established by the realization of a WG on/off switch for arbitrary time periods.The AOMID concept is an extension of the acoustically driven MZIs of Fig. 1͑a͒ for a number N P ജ 2 of WG arms connected in parallel. 8 The configurations for N P =2 ͑corre-sponding to the simple MZI͒, N P = 4, and N P = 8 are illustrated in Figs. 1͑a͒-1͑c͒. In each case, the single mode WGs ͑numbered by the index p =1, ... ,N P ͒ are assumed to be identical and much narrower than SAW . The WGs are aligned perpendicularly to the SAW propagation direction and displaced laterally so as to experience SAW phases differing by a multiple of SAW =2 / N P . The amplitude max of the light phase shift upon propagation through the WGs is related to the WG length ᐉ and to the refractive index modulation ␦n induced by the SAW strain by max =2 ␦nᐉ / L , where L is the light wavelength. The use of symmetric Y-splitters in Fig. 1 ensures unity transmission in the absence of a SAW. Under the previous assumptions, the transmission T P of an AOMID with N P arms becomes:where f SAW is the SAW frequency. Figure 1͑d͒ comp...

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“…Continuing with the analysis of this effect, the reimage that comes out of the MMF has been used in order to get an optical device (Soldano et al, 1992;Li et al, 2002;Selvas et al, 2005;Anzueto-Sanchez et al, 2006;Mehta et al, 2003). All these works used a high reflector mirror to get the light back into the MMF again as is showed in Fig 2. The analysis goes further because of the free space condition.…”

Section: Multimode Interference Effectmentioning

confidence: 99%

“…The self-imaging feature of a homogeneous multimode planar optical waveguide has been applied in the design of passive planar monomodal optical couplers based on multimode interference (MMI) (Soldano et al, 1992). This characteristic is described as an input field profile which is reproduced in single or multimode images by mode interference at periodic intervals along the propagation direction of the guide.…”

Section: Multimode Interference Effectmentioning

confidence: 99%