Research On Improved Polymer Waveguide Optically Controlled Switch Based On Graphene

Optical switch plays an important role in the field of optical communication.With the development of optical switch array,people put forward higher requirements on the cost and power consumption of optical switch.Organic polymer materials have high thermal-optical coefficient,low cost and simple processing technology,which are very suitable for application in optical switches.But thermal-optical switching requires photoelectric conversion,which increases switching time.The appearance of all-optical switch solves this problem and increases the switching speed by an order of magnitude.Graphene-assisted all-optical switch has gradually become a hot spot in the research of all-optical switch due to its advantages of fast response speed and low power consumption.In this paper,graphene is used in polymer waveguide optical switches by taking advantage of the unique saturable absorption properties and photothermal effects of graphene,which greatly reduces the signal loss.The main content of this paper is divided into the following two parts:1.A graphene-assisted polymer waveguide optically controlled switch using firstorder mode is proposed.It can reduce the absorption of graphene,thus achieving lower transmission loss.The switch uses Mach–Zehnder interferometer structure,a monolayer of graphene embedded in a polymer waveguide,and the first-order mode signal light is used to reduce transmission loss.Graphene absorbs 980 nm pump light and controls the opening and closing of 1550 nm signal light using the heat generated by the photothermal effect.Simulation results showed that when graphene is in the right position,the power consumption is 9.5 m W,the transmission loss is 0.01 d B/cm,and the rise time and fall time of the switch are 127 μs and 125 μs,respectively.Switching times can be reduced to 106 μs（rise time）and 102 μs（fall time）using a silicon substate with high thermal conductivity.Compared with fiber optic all-optical switch,the proposed switch in this paper has lower power consumption and transmission loss.Due to the low cost and easy integration of polymer materials,its device is bound to play an important role in the field of all-optical signal processing and silicon-based hybrid integrated photonic devices.2.All optical absorption switch is prepared experimentally.When graphene produces saturation absorption of 980 nm pump light,1550 nm signal light passes through.In the absence of pump light,the graphene absorbs the signal light at 1550 nm,and the signal light cannot pass through.The core of the switch is the polymer SU-8,and the upper cladding is polymethyl methacrylate.The lower cladding is silicon dioxide.The polymer waveguide was fabricated by wet etching.The switching structure was straight waveguide,and the switching test was carried out.During the test process,the signal light and pump light were passed into the switch by a wavelength division multiplexer.The power consumption of the switch is 70.8 m W,the extinction ratio is 17.1 d B,the rise time of the switch is 220 μs,the fall time is 294.5 μs,and the switching function could be realized.Compared with fiber optic all-optical switches,the switches this paper proposed have simple preparation process,low cost and lower power consumption.