ﻃﺮاﺣﯽ ﺗﺰوﯾﺞﮔﺮ ﻏﯿﺮﺧﻄﯽ ﭘﻼﺳﻤﻮﻧﯽ ﺑﺎ ﺑﺎزدﻫﯽ ﺗﺰوﯾﺞ ﺑﺎﻻ در ﻣﺤﺪوده ﺑﺎﻧﺪﻫﺎي ﻣﺨﺎﺑﺮات ﻧﻮري

Design of a Nonlinear Plasmonic Coupler with High Coupling Efficiency over All Optical Communication Bands

ﭼﮑﯿﺪه: ﯾﮑﯽ از ﭼﺎﻟﺶ ﻫﺎي ﻣﻮﺟﻮد در ادوات ﻧﻮري ﺑﻪ ﺧﺼﻮص ﺗﺰوﯾﺞ ﮔﺮﻫﺎ، ﮐﺎﻫﺶ اﺑﻌﺎد و ﺗﻠﻔﺎت ﮐﻠﯽ ﺳﺎﺧﺘﺎر اﺳﺖ. در اﯾﻦ ﻣﻘﺎﻟﻪ ﯾﮏ ﺗﺰوﯾﺞ ﮔﺮ ﺟﻬﺖدار ﭘﻼﺳﻤﻮﻧﯽ ﻏﯿﺮﺧﻄﯽ ﮐﻪ ﺷﺎﻣﻞ دو ﻣﻮﺟﺒﺮ MIM )ﻓﻠﺰ-دي اﻟﮑﺘﺮﯾﮏ-ﻓﻠﺰ( اﺳﺖ، ﭘﯿﺸﻨﻬﺎد ﺷﺪه اﺳﺖ. در اﯾﻦ ﻃﺮح، از ﯾﮏ زاﺋﺪه ذوزﻧﻘﻪاي ﺷﮑﻞ در ﻧﺎﺣﯿﻪ ﻣﻮﺟﺒﺮ ورودي و ﺧﺮوﺟﯽ ﺟﻬﺖ ﮐﺎﻫﺶ ﻃﻮل ﺗﺰوﯾﺞ اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ و ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ اﺛﺮ ﮐﺮ در ﻣﺎده ﻏﯿﺮﺧﻄﯽ ﻣﻮﺟﺒﺮ دياﻟﮑﺘﺮﯾﮏ، ﻣﯿﺰان اﻧﺘﻘﺎل ﺗﻮان در ﺧﺮوﺟﯽ ﻫﺎ ﮐﻨﺘﺮل ﭘﺬﯾﺮ اﺳﺖ. ﻧﺘﺎﯾﺞ ﺗﺤﻠﯿﻞ ﻋﺪدي ﺗﻮﺳﻂ روش ﺗﻔﺎﺿﻞ ﻣﺘﻨﺎﻫﯽ در ﺣﻮزه زﻣﺎن ﻧﺸﺎن ﻣﯽ دﻫﺪ ﮐﻪ ﺑﺎزدﻫﯽ ﺗﺰوﯾﺞ و ﻃﻮل ﺗﺰوﯾﺞ ﺳﺎﺧﺘﺎر ﭘﯿﺸﻨﻬﺎدي در ﺗﻮان ورودي 4W/µm و ﻃﻮل ﻣﻮج 1550nm، ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺮاﺑﺮ 90% و 650nmاﺳﺖ. ﻫﻤﭽﻨﯿﻦ، در ﻃﻮل ﻣﻮج 1310nm و در ﺗﻮان ورودي 25W/µm ، ﺑﺎزدﻫﯽ ﺗﺰوﯾﺞ ﺑﺮاﺑﺮ 92% و ﻃﻮل ﺗﺰوﯾﺞ آن ﺑﺮاﺑﺮ ﺑﺎ 510nm ﺑﻪ دﺳﺖ ﻣﯽآﯾﺪ. ﺑﻨﺎﺑﺮاﯾﻦ ﻃﺮح ﭘﯿﺸﻨﻬﺎدي در ﺣﺎﻟﺖ ﺗﻮان ورودي ﮐﻢ، داراي ﺑﺎزدﻫﯽ ﺗﺰوﯾﺞ ﺑﯿﺶ از 80% در اﮐﺜﺮ ﺑﺎﻧﺪﻫﺎي ﻣﺨﺎﺑﺮاﺗﯽ )1260nm ﺗﺎ 1675nm( اﺳﺖ.

There are two important issues in the design of optical devices and in special in optical couplers; down scaling and loss reduction. In this paper, a nonlinear plasmonic directional coupler consisting of two MIM (metal- insulator- metal) waveguides is proposed. In order to reduce the coupling length, part of the waveguides structure is designed in the shape of a trapezoid. Numerical analysis using finite-difference time-domain method shows that the coupling length of this scheme is 510nm for the input power of 100W/µm and at the wavelength of 1310nm. Also, the proposed coupler exhibits the coupling efficiency of more than 80% for the input power of 100W/µm over all the optical communication bands (1260-1675nm). The other property of this coupler is being able to control the output power which is the advantage of using the nonlinear waveguides.