Processing,Characteristic Testing And The Optimization Design Of Optical Coatings For 1.3um Superluminescent Diode

Because Superluminescent diode have these excellent performance such as high-power,wider spectrum and short coherent length and so on,so it can be widely used in fiber optical gyroscopes(FOG),optical coherence tomography(OCT),wavelength division multiplexing(WDM)optical fiber communication and optical processing system. At present the theory for superluminscent diode have been developed very well.So we have to improve the progressing and make new device structure to meet he need for high performance device.In this paper we put emphasis on the progressing of SLD.,we can get the result.Following is the details:In the process of produced titled ridge waveguide SLD,the major key processing is following.The first is photolithographic processing.In order to reduce the loss of light in transmission,the edge of waveguide must be as straight as possible.So after photolithographic and develop processing,the edge of photoresist required clear and straight.In the base of other appropriate parameter,we do some experiment and compare the result,then find by using MF320:H₂O(2:1)dilute developer we can got better result. The edge of waveguide is clear and straight.The process of experiment also can easy controllable.The second is mesa etching.In the mesa etching processing,we used the wet chemical selective etching,wet chemical unselective etching and combine dry and wet ecting.Compared the three result,we find that the selective etching is better than others, the angle of mesa etch is smaller,and the mesa is more parallel.It can meet the device request.The third is ohmic contact.By using the circular transmission method,we test the specific contact resistance between the different adulterate concentration of P-InGaAs and Ti-Au.After different temperature anneal,we find the lowest contact resistance can reach 1.74×10^-5Ω·cm² under the 350℃anneal and the adulterate concentration 1.5×10¹⁹cm^-3.Thought using different surface treatment methods on the InGaAs material,we find after etch appropriate thickness surface treatment the specific contact can be obviously improved.Afterward we test theⅠ-Ⅴcharacteristic of the diode core,it can be improved by 350℃anneal and do the surface treatment before made P-type electrode.In the base of these result of the key processing,we can go on wheels to make the superluminescent diodes.We test the device spectrum and the light power curve.Under the 150mA CW test condition,the center of spectrum in all different angle titled ridge device is 1.3um,the widest of spectrum width reach 104.3nm.The largest light power is closed 10mW in the room temperature.Plating the anti-reflection coating can effectively improve the SLD optical performance.In the paper thought study these optimization design methods and compare the result of these methods,the PA algorithm is more effective than others.The film which design by PA algorithm have minimum disparity with the idea circs.Finally we can got the amount of anti-reflection coating is 5.The lowest reflectivity is 0.8%and the width of the reflectivity spectrum is about 80-100nm.The thickness of each film is regular thickness (d=λ/4).