fig1 schematically shows an optical network 1 according to the present invention comprising a main station 2 communicating via a passive optical network 3 of glass fibres with a plurality of substations 4 , 5 , and 6 . the substations 4 , 5 , and 6 are coupled to a passive splitter 7 . the main station 2 can be a head - end of a multi - media communication network such as a catv - network allowing bidirectional communication and offering a plurality of services such as traditional catv services , interactive tv services , video - on - demand , or the like , the head - end being a so - called optical light termination or olt . the main station 2 can also be a head - end of a tpon ( telephony over a passive optical network ). the network can also comprise light amplifiers ( not shown ). the substations 4 , 5 , and 6 can be optical network units or so - called onus allowing bidirectional communication with the olt . the onus can be onus to the curb , to the building , or to the home . in the given example , the network 1 is a subcarrier multiple access passive optical network wherein bit streams are modulated on separate carrier . such a network is described in more detail in the article &# 34 ; analysis and design for optical video transport / distribution system with video on demand service &# 34 ;, t . tsuchiya et al ., journal of lightwave technology , vol . 11 , no . 1 , jan . 1993 , pp . 106 - 115 . the main station 2 can also be a local telephone exchange , the substations 4 , 5 , and 6 then having access to various services such as broadband telephone services , facsimile , or the like . the network 2 can also offer combined telephony and video / audio services . to this end , the main station 2 comprises a plurality of analog , and / or digital bi - directional channels 8 , 9 , and 10 . in the given example bi - directional digital channels are shown to which bitstreams 11 , 12 , and 13 are supplied , respectively , but the present invention is not depending on the kind of modulation technique and the kind of signals that are applied . all subcarrier modulated channels are modulated in a laser driver 14 onto a common light wave carrier so as to form a subcarrier multiplexed signal . for allowing bi - directional communication the main station 2 further comprises a broadband optical receiver 15 . the laser driver 14 and the optical receiver 15 are coupled to a 1 : 2 optical splitter 16 . fig2 shows a block diagram of the substation 4 in the network 1 according to the present invention . the substation 4 comprises an optical receiver 20 according to the present invention , a modulator / laser driver 21 for driving a laser diode 22 with a bitstream 23 at an input 24 of the modulator / laser driver 21 . a more detailed description of such a modulator / laser driver 21 , which is well - known in the art , can be found in the handbook &# 34 ; optical fibre communications &# 34 ;, j . m . senior , prentice - hall int , inc ., london , 1985 , pp . 460 - 463 , and pp . 467 - 472 . in the given example , the optical receiver 20 provides a demodulated datastream 25 . fig3 shows a first embodiment of the optical receiver 4 according to the present invention . the optical receiver 4 comprises a tunable frequency selective front - end section 30 formed by a parallel resonant electrical circuit of an inductor 31 , a varicap diode 32 , and a capacitor 33 . the parallel resonant electrical circuit can be electrically tuned by means of a tuning voltage to be supplied at a terminal 34 via a resistor . the bandwidth of the resonant circuit must such as to allow selection of one channel from the received subcarrier multiplexed signal from the network 3 . the optical receiver 4 further comprises a front - end dual gate fet amplifier 36 with appropriate biasing and coupling elements such as the resistor 37 , and the capacitor 38 to ground . a band selection network formed by capacitors 39 , 40 , and 41 , by resistors 42 , and 43 , and by inductor 44 is shown , a band selection signal to be applied to a terminal 45 . further shown is a terminal 47 for supplying an agc voltage ( automatic gain control ) via a resistor 48 to the dual gate fet amplifier 36 . to this point , the described circuit corresponds to a part of an uhf - tuner as disclosed in the datasheet of the uv815 / uv816 series tv - tuners , data handbook &# 34 ; television tuners &# 34 ;, philips components , book dc03 , march 1992 , pp . 77 - 91 . this uhf - tuner is designed for a frequency band of 450 - 860 mhz . further components of this tv - tuner as disclosed in said handbook , namely oscillators , mixers , and if - amplifiers are well - known . in fig3 this known circuitry is indicated with an interrupted drain lead of the fet 36 . the if - signal as provided by such a tuner is fed to well - known baseband demodulation circuits . according to the present invention , the optical receiver 4 further comprises a reverse biased photodiode 49 which is directly coupled to the tunable frequency selective front - end section 30 . a reverse bias voltage is supplied to the photodiode 49 via a terminal 50 . an ac - decoupling capacitor 51 is connected between the terminal 50 and ground . reverse biasing advantageously achieves that the parasitic capacitance of the photodiode 49 is as small as possible thus hardly influencing the parallel resonant circuit . instead of an electrically tuned varicap , also a mechanically tuned capacitor ( not shown ) can be used . for parallel selection of more than one channel , either in the same or in another frequency band , further tunable frequency selective front - end sections and / or with further photodiodes can be applied . as such an extension is straightforward , no details are shown here . fig4 shows a second embodiment of the optical receiver 4 according to the present invention . instead of a parallel resonant circuit a series resonant circuit is shown , formed by the varicap diode 32 , and an inductor 60 . instead of a fet a bipolar transistor 61 is applied . for dc - coupling an rf - choke 62 is provided for dc - coupling to ground . an ac - decoupling capacitor 63 is provided . fig5 shows a third embodiment of the optical receiver 4 according to the present invention . instead of the inductor 31 , an auto - transformer with windings 31a and 31b is provided , the photodiode 49 being coupled to a junction of the windings 31a and 31b . fig6 shows a fourth embodiment of the optical receiver 4 according to the present invention . instead of the inductor 31 , a transformer with windings 31c and 31d is provided , the photodiode 49 being coupled to the winding 31c , and the varicap diode 32 being coupled to the winding 31d . the windings 31c and 31d can be air - coupled or can be coupled by means of a core such as a ferrite core 65 . fig7 shows a fifth embodiment of the optical receiver 4 according to the present invention . instead of the photodiode 49 a photo - transistor 70 is provided , the tunable frequency selective front - end section 30 being coupled to a collector 71 of the photo - transistor 70 , and an emittor 72 of the photo - transistor being coupled to a terminal 73 for supply of a negative bias voltage thereto via a resistor 74 , and to ground via a capacitor 75 for ac - decoupling . the foregoing merely illustrates the principles of the invention . it will thus be appreciated that those skilled in the art will be able to devise various arrangements which , although not explicitly described or shown herein , embody the principles of the invention and are thus within its spirit and scope .