1
Richard E Epworth: Optical transmission system. International Standard Electric Corporation, John T O Halloran, Peter R Ruzek, August 6, 1985: US04533247 (151 worldwide citation)

An optical transmission system comprises a light source, which may be coherent or incoherent, a first optical interferometer wherein light from the source is modulated, an optical path, which may be either free space or an optical fiber, along which the modulated output of the first interferometer i ...


2
Richard E Epworth: Optical frequency modulation system. International Standard Electric Corporation, John T O Halloran, Peter R Ruzek, December 24, 1985: US04561119 (86 worldwide citation)

An optical communication system including at a transmitter a semiconductor laser (2) and at a receiver a photodetector (3). Intermediate the transmitter and the receiver is an optical frequency discrimination (4), e.g. a Fabry-Perot resonator. The laser (2) is operated at a substantially constant av ...


3
Richard E Epworth: Optical transmission system. Northern Telecom, Lee Mann Smith McWilliams Sweeney & Ohlson, October 31, 1995: US05463487 (57 worldwide citation)

In a wavelength division optical transmission system incorporating optical amplifiers, an identifying pilot tone is modulated on to each multiplexed wavelength. Each system amplifier determines from the pilot tones the total number of wavelengths being transmitted and thereby provides a correspondin ...


4
Paul A Kirkby, Richard E Epworth: Transmission systems incorporating optical amplifiers. Northern Telecom, Lee Mann Smith McWilliams Sweeney & Ohlson, September 19, 1995: US05452116 (55 worldwide citation)

In a wavelength multiplexed optical transmission system incorporating a concatenation of optical amplifiers the multiplexed signal passes through a limited number of amplifiers in which all channels are amplified together, after which, at the next amplifier, the signal is demultiplexed, each channel ...


5
Richard E Epworth: Optical fibre transmission systems. STC, Lee Mann Smith McWilliams & Sweeney, September 4, 1990: US04953939 (45 worldwide citation)

A device for producing an optical delay in an optical signal having variable optical frequency, the optical delay varying with the optical frequency, comprises a chirped Bragg reflector formed in an optical fiber and a directional coupler for separating the reflected signal from the input signal. On ...


6
Richard E Epworth, Kevin C Byron, Robert A Baker, Nigel Taylor: Optical amplifier gain control. STC, Lee Mann Smith McWilliams & Sweeney, May 26, 1992: US05117196 (40 worldwide citation)

The gain of an optical amplifier is maintained constant by employing a portion of the amplified optical signal in a feedback loop. In one arrangement this is used to control the output of a pump signal source accordingly. The portion of the said signal corresponds to spontaneous emission (ASE) at a ...


7
Richard E Epworth: Balanced coherent receiver. STC, Lee Smith & Zickert, January 5, 1988: US04718121 (36 worldwide citation)

In a coherent optical receiver using balanced photodetectors, local oscillator intensity fluctuations are nulled out by cross-correlating them with an imperfectly balance output to derive an error signal used in a feedback loop to optimize the balance.


8
Richard E Epworth, Andrew N Robinson, Moira J Stewart: Optical amplifiers. Northern Telecom, Lee Mann Smith McWilliams Sweeney & Ohlson, March 4, 1997: US05608571 (26 worldwide citation)

An optical amplifier for a wavelength multiplexed transmission system has a set of optically amplifying fibres (26a, 26b) each provided with an associated spectrally selective Bragg reflector (27a, 27b). The amplifying fibres are optically coupled with a coupler (23) such that an optical signal havi ...


9
Norman D Leggett, Richard E Epworth: Planar laser mount. International Standard Electric Corporation, John T O Halloran, Peter C Van Der Sluys, March 13, 1979: US04144504 (20 worldwide citation)

An injection laser mount assembly comprises a housing having a front surface extending in a plane parallel with a rear surface. The front surface has a central recess from which a pillar extends for carrying a laser. Optical coupling can be made with the laser by converting the mount assembly to an ...


10
Richard E Epworth: Chirped distributed Bragg grating optical fibre filters. Northern Telecom, Lee Mann Smith McWilliams Sweeney & Ohlson, February 11, 1997: US05602949 (18 worldwide citation)

A distributed Bragg grating of uniform pitch is created in a length of unstrained optical fibre which is then secured in an arcuate path to a flexible plate so as to be displaced from the neutral surface of bending of that plate. Changing the curvature of the plate imparts axial strain in the fibre ...