14 Sep 2018




 Date: 10-09-2018


  1. 50 students of ECE II year visited the ALTTC, Ghaziabad between on 28-08-2018.


  1. Attendance of the section is attached with this report.


  1. Center comprises of three different labs named as following,
    • Broadband Lab
    • Dense Wave Division Multiplexing Lab
    • Optical Fiber Lab


  1. Broadband Lab
    • Students learnt about Digital Subscriber Line and how data frames flows to other part of the world.
    • They learnt about usages of MODEM, splitter to split data and voice frames, ADSL, and transmission line T1 & T2 carrier systems.
    • Lab instructor talked about the services that are supported as content-based services, videomulticastingvideo-on-demandaudio and video conferencingIP telephonydistance learning, messaging, multi-site MPLS VPNs with Quality of Service (QoS) guarantees.
    • Students learnt that data services are given through Multi-Protocol Label Switching(MPLS) based IP infrastructure. Layer 1 of the network will consist of a high-speed backbone composed of 24 core routers connected with high-speed 2.0 Gbit/s links.


  1. Dense Wave Division Multiplexing (DWDM) Lab
    • Students got through how Wave division multiplexing is used to combine the data in optical format. As all the communication traffic in modern day, passes through fiber hence it is important to go through this type of scheme.
    • A basic DWDM system contains several main components:
      • DWDM Terminal Multiplexer: The terminal multiplexer actually contains one wavelength converting transponder for each wavelength signal it will carry. The wavelength converting transponders receive the input optical signal, convert that signal into the electrical domain, and retransmit the signal using a laser.
      • Intermediate Line Repeater is placed approx. every 80 – 100 km for compensating the loss in optical power, while the signal travels along the fiber. The signal is amplified by an EDFA, which usually consists of several amplifier stages.
      • Intermediate Optical terminal: This is a remote amplification site that amplifies the multi-wavelength signal that may have traversed up to 140 km or more before reaching the remote site. Optical diagnostics and telemetry are often extracted or inserted at such a site, to allow for localization of any fiber breaks or signal impairments. In more sophisticated systems (which are no longer point-to-point), several signals out of the multi-wavelength signal may be removed and dropped locally.
      • DWDM Terminal De-multiplexer: The terminal de-multiplexer breaks the multi-wavelength signal back into individual signals and outputs them on separate fibers for client-layer systems to detect.
      • Optical Supervisory channel: This is an additional wavelength usually outside the EDFA amplification band (at 1510 nm, 1620 nm, 1310 nm or another proprietary wavelength). The OSC carries information about the multi-wavelength optical signal as well as remote conditions at the optical terminal or EDFA site. It is also normally used for remote software upgrades and user (i.e., network operator) Network Management information.


  1. Optical Fiber Lab
    • Students got the practical aspects of Optical Fiber, its construction, geometry, etc. Instructor taught about the basic principle of Optical Fiber communication that is total internal reflection. There were different types of optical cables as single mode, multi-mode, etc.
    • Students analyzed the OTDR which is Optical Time Domain Reflectometer (OTDR) is an optoelectronic instrument used to characterize an optical fiber. An OTDR is the optical equivalent of an electronic time domain reflectometer. It injects a series of optical pulses into the fiber under test and extracts, from the same end of the fiber, light that is scattered (Rayleigh backscatter) or reflected back from points along the fiber. The scattered or reflected light that is gathered back is used to characterize the optical fiber. This is equivalent to the way that an electronic time-domain meter measures reflections caused by changes in the impedance of the cable under test. The strength of the return pulses is measured and integrated as a function of time, and plotted as a function of fiber length.